The Engineering Design Process

002.

Apply the concepts and principles of the engineering design process

002.01

Explain the linear design process

002.02

Explain the concurrent engineering design process

002.03

Apply design concepts and principles to solve problems

UNIT B: The Engineering Design Process

Competency: D502.00

Explain the concepts and principles of the engineering design process.

Objective: D502.01

Explain the linear design process.

Introduction: The purpose of this unit is to show that the design process is a challenging effort, and the designer relies heavily on the use of graphics as a means to create, record, analyze and communicate to others. The engineering design process is used to solve society’s needs, desires, and problems through the application of scientific principles, experience, and creativity.

(R1 398-411, R2 49-53)

Explain the following:

Design is the conception of an idea and its development, through graphic communication, into a practical, producible, and usable product or process.

Functional design is the design of a product so that it operates successfully or accomplishes its purpose.

Aesthetic design is the form or overall physical appearance of the product. Aesthetics involves characteristics such as color, line, style, space, contrast, proportion and balance.

In the development of any product, designers use knowledge, creativity, experience, and resources to create a new or improved product. The design must be functionally efficient, meet the design objective, and be aesthetically appealing.

In the linear design process, a designer takes the design of a product from the initial design problem or idea stage and carries it through, step by step, until it is turned over to the production division.

A design or idea starts with the recognition of a problem or the determination of a need or want. The designer carefully analyzes the idea to determine if it is practical and marketable.

Next, alternative designs are gathered to create possible product solutions. All notes and sketches are signed, dated, and retained for further work and possible patent proof.

At this point the best solution is evaluated in detail, and attempts are made to simplify the design so that it performs efficiently and is easily manufactured. Materials and costs are carefully considered. A design layout drawing is made to show basic proportions of parts and how they fit together in an assembly drawing.

After the most feasible solution is selected, a prototype is constructed to test the design. The prototype can be a physical model or a computer-generated model of the design.

Once the engineering team or a select group of consumers has evaluated the prototype, the feedback is used for changes to the design. The design process then loops back to previous stages for final consideration before the manufacturing of the product.

Finally, a set of working drawings are prepared, and the design is sent into production.

Linear Engineering Design Process

Stage 1 - Identification of Design Problem

Problem identified

Analysis of need, market research

Costs (estimated cost limit)

Design requirements (essential, important,

desirable, or beneficial)

Time-line, scheduling

Stage 2 - Problem-Solving Concepts and Ideas

Concepts and ideas collected and recorded

Legal requirements (patents)

Material requirements

Manufacturing requirements

Overall size requirements

Stage 3 - Compromise Solutions

Compromise solutions

Initial design sketches are refined

3D modeling

Inventions (starting from scratch) vs.

Evolutionary Designs (the 2004 model)

Stage 4 - Models & Prototypes (Analysis)

Creating a prototype (machined, rapid

prototyping, electronic prototype, etc.)

Kinematic/motion testing

Life testing

Finite element analysis (stress/strain)

Thermal analysis

Stage 5 - Production or Working Drawings

How is information passed to production?

Working drawings

Computer Numerical Control (CNC)

Computer-Aided Manufacturing (CAM)

Figure 1. The Linear Design Process.

UNIT B: The Engineering Design Process

Competency: D502.00

Explain the concepts and principles of the engineering design process.

Objective: D502.02

Explain the concurrent engineering design process.

Explain the following:

Concurrent engineering design is done in a comprehensive team environment. The team consists of designers, engineers, drafters, and others associated with the overall design, manufacturing, marketing, and servicing of the product.

Figure 1. Lines of Communication within Concurrent Engineering Design.

In addition to the basic functional and aesthetic design concepts, the team considers important issues such as manufacturability, quality, life cycle, costs, and whether the finished product will meet the original design objectives.

In concurrent engineering design, a comprehensive 3D CAD and computerized engineering database serves as the nucleus for all aspects of design, manufacture, and marketing of the product.

1. The database can be accessed by anyone on the design team.

2. The team members do not have to be at the same location. They can be anywhere in the world.

Concurrent engineering is concerned with making better products in less time, so continuous quality improvement techniques are practiced throughout the product’s life cycle.

1. The product’s life cycle is its total life, from the conception of the idea to the recycling of the materials from which it is made.

2. The life cycle is considered as early as possible.

Ideation, refinement, and implementation are the three overlapped areas of concurrent engineering design.

Ideation is a structured approach to thinking for the purpose of solving a problem. Ideation is the beginning phase where the design problem is identified, preliminary solutions are developed and the preliminary design is agreed upon.

Problem Identification includes activities such as:

writing a problem statement

conducting research

gathering data

defining objectives for the project

determining limitations of the design

outlining a reasonable schedule

Preliminary Ideas includes activities such as:

writing and collecting notes about the project

creating sketches and/or models of the design

brainstorming design ideas

synthesizing the design ideas

Preliminary Design includes:

evaluating preliminary ideas

selecting a design

Refinement follows the ideation process. It is a repetitive process used to test the preliminary design. It includes preparation of models and prototypes, thorough physical, production, and legal analysis of the design, and design visualization, or analysis of the aesthetics.

Modeling – this includes geometric modeling, simulation, animation, and developing charts, graphs and diagrams.

Design Analysis – this area includes material property analysis, mechanism analysis, functional analysis, and human factors analysis.

Design Visualization – design visualization includes rapid prototyping, manufacturing visualization, and simulations.

Implementation is the final phase of concurrent engineering design. It involves careful analysis of production, financing, servicing, documenting, final planning, and life cycle issues.

Because the phases overlap and the entire team works on every element of the design, there is significant improvement in quality and a reduction in project time, cost and changes during production.

Figure 2. The Concurrent Engineering Design Process.

UNIT B: The Engineering Design Process

Competency: D502.00

Demonstrate the concepts and principles of the engineering design process.

Objective: D502.03

Apply design concepts and principles to solve problems.

Requirements: Each student is required to develop a working design that follows the given criteria.

1.	Using the drafting software provided, design a track for a toy train.

2.	The end product must conform to the following design criteria:

The track will be thermoformed on a 2 feet by 3 feet sheet of plastic that is .125 of an inch thick.

To reduce waste as much of the plastic as possible should be used. The track should include enough sections that, when assembled, there will be a closed loop with no extra pieces.

Figure D502.03.01

Example Track

For cost reduction, there should only be two types of sections: one circular and one linear. The sections can be any size in length or width.

The model train that will run on these tracks has a total axel and wheel width of 2 inches; Therefore, the design must have a raised indenture uniformly around the entire track that is 2 inches wide (refer to drawing Figure D502.03.001).

Figure D502.03.02

Example Track Section

The raised indenture should be .20 inches total width (refer to drawing Figure 00X.0X.02).

The drawing must show that the thickness, including raised and recessed areas, is uniform .125 of an inch.

Complete an initial pattern layout. Each piece should have at least .125 of an inch between one another on the layout for mold and shearing purposes.

Figure D502.03.03

Example Pattern Layout

When the layout is complete and all sizes are final, model a linear and circular section with the drafting software provided.

Figure D502.03.04

Example Rendering of Track Sections

Create an assembly showing how each piece will connect in a complete loop.

Figure D502.03.05

Example of Assembly in a Complete Loop

From the models, create additional drawings. Include a multiview of each type of track section with complete dimensioning and a final pattern layout (refer to Figure 00X.0X.06).

Figure D502.03.06

Example of Final Pattern Layout

4.	Place the multiviews on sheets of appropriate size. Add your name, part name, problem number (D502.03.001), scale, and date in the title block.

5.	Print a Final Pattern Layout, an Assembly of the Complete Loop, and the multiviews of a linear section and a circular section. There will be four drawings in the final product.

6.	Time Limit = 180 minutes.

7.	Your work should reflect an understanding of design concepts and principles and the relevance of drafting standards to problem solving applications.

Assessment: The problem will be evaluated based on the following criteria:

Criteria	Point Range

Pattern Layout	25 points

Completion of Multiviews	20 points

Completion of Assembly	25 points

Design and Problem Solving	30 points

Rubric for ENGINEERING TOPIC – Apply design concepts and principles – D502.03.001

Pattern Layout

Layout was not balanced, did not include all track sections, and did not conform to several design specifications.	Layout included all sections of track, but did not follow all design specifications.	Final layout reflects how parts will be formed on a 2’ X 3’ sheet of plastic. There is .125 of an inch between each track section. There are two types of track sections, linear and circular.	Total Points
0-18 points	19-21 points	22-25 points

Completion of Multiviews

Drawings do not follow drafting standards. There are several dimensions missing. Views may be missing or incomplete. The drawings do not conform to most of the design specifications.	Drawings are missing some dimensions. Drawings follow most of the design criteria specifications but not all.	Drawings follow all drafting standards. There is a raised indenture with an overall distance of 2.00 inches and a width of .20 for the train wheel. The drawings show a uniform thickness of .125. Drawings contain all necessary dimensions for part reproduction and titleblock is complete.	Total Points
0-14 points	15-18 points	19-20 points

Completion of Assembly

Track has been designed poorly. Models do not fit together due to excessive miscalculation.	Track is together except for one or two pieces of the model that can not be assembled because of miscalculations.	Models are assembled and constrained to mating parts to show how the track will be assembled. The number of pieces assembled reflects the same number of pieces shown on the layout. Track sections make a continuous loop.	Total Points
0-18 points	19-21 points	22-25 points

Design and Problem Solving

Design did not follow design criteria given.	Design satisfies most of the criteria given with few mistakes in calculation, layout, and assembly.	Design is complete, original and satisfies all design criteria given. There is a minimal amount of waste on pattern layout, parts are uniformly .125 of an inch thick, and track fits together in an enclosed loop without excess pieces. Track section ends have male/female features for assembly.	Total Points
0-20 points	21-25 points	26-30 points

Total Score

Constraint-Based Parametric Modeling

003.

Demonstrate the concepts and principles of constraint-based parametric solid modeling

003.01

Explain the terminology related to constraint-based/parametric solid modeling

003.02

Explain the concepts related to constraint-based/parametric solid modeling

003.03

Create solid models using a constraint-based/parametric solid modeler

UNIT C: Constraint-Based/Parametric Solid Modeling

Competency: D503.00

Demonstrate the concepts and principles of constraint-based/parametric solid modeling

Objective: D503.01

Explain the terminology related to constraint-based/parametric solid modeling

Introduction: The purpose of this unit is to give a foundation for the topic of constraint-based or parametric solid modeling. Over the last decade, computer-aided design technology has drastically changed in the area of 3D modeling. No longer is the drawing the primary means of communication between the designer and manufacturing when producing metal or plastic parts. In fact, some companies go directly from the 3D data produced by the designer or engineer to the final part. This is done by transferring the 3D data to computer numerical control (CNC) machines or sending the data to have molds developed for forming plastics.

SolidWorks®, SolidEdge®, Inventor®, Pro/Engineer®, and ProDesktop® are constraint-based CAD programs. They all function in a similar fashion. The biggest difference between these programs and software such as AutoCAD® is the way they take advantage of the 3D database. Within the constraint-based modeler environment, the 3D solid model or part is typically the first type of file that is created. Once the part files are created, assemblies and drawings of parts can be generated. Most of these programs take advantage of bidirectional associativity between the files. In other words, if a dimension is changed in the model, the drawing file and assembly files automatically update. If a change is made in the drawing file, the change is reflected in the part and/or assembly files. As you can probably imagine, this type of environment for designing parts is much different than laying out 2D drawings. Students who can master this type of software will be much more efficient and productive.

Define the following:

Constraint-based modeling software – constraint-based modeling software is a type of CAD software that uses feature definitions (extrude, revolve, fillet, etc.), dimensional and geometric constraints (equal, parallel, concentric, etc.), and a feature tree (how the features are arranged) to define 3D solid models. See Figure 1 for an illustration of the different types of files with a constraint-based modeler.

Part file – a part file is an individual solid model file within a constraint-based CAD system. A part file contains information about the part’s 2D and 3D geometry, appearance, material properties, and annotations or notes.

Assembly file – an assembly file is a type of file used within a constraint-based CAD system to organize individual parts and/or assemblies to create a more complex representation of a product. Assembly files contain information about how parts are constrained relative to one another.

Drawing file – a drawing file is used to create traditional 2D documentation of objects within a constraint-based CAD system. Drawing files typically include traditional views (top, front, right-side, bottom, left-side, rear, auxiliary, sectional, and pictorials), dimensions (standard, tolerance, and geometric), and annotations or notes (including titleblocks and borders).

Construction plane or Workplane – construction planes or workplanes are the most common type of construction geometry within constraint-based CAD systems. They are planes in 3D space used to define global (world) and local (user defined) coordinate systems. They can be imaginary planes or surfaces on the existing solid model.

Sketch or Profile – Within the context of constraint-based modeling, a sketch or profile is the 2D geometry created on a construction plane or workplane which is used with some type of sweeping operation (extrude, cut-extrude, revolve, cut-revolve, loft, sweep, etc.) to create a solid model.

Feature – a feature is a physical portion of a solid model that appears in the feature tree. Features can be extrudes, revolves, sweeps, lofts, fillets, chamfers, etc.

Feature definition –feature definition is the method a constraint-based CAD system uses to keep track of the parameters for each individual feature that makes up a solid model. Swept features are defined by a construction plane or workplane, a sketch or profile with dimensional and geometric constraints, a path or direction, and a distance or angle. Other features such as fillets, chamfers, and shells are not defined by a sketched profile but by other parameters usually selected from a dialog box within the software.

Feature tree – a feature tree (sometimes called a browser, modeling tree, history, or feature manager design tree) is a list of the geometric features that exist within a model file in the order in which they are interpreted by the modeler. Features in the tree can be construction geometry (origins, planes, axes, etc.), part features (extrudes, revolves, sweeps, lofts, fillets, etc.), or components in an assembly file.

Constraints – constraints are the mathematical requirements placed on the geometric elements in a 3D solid model. They control the geometric behavior of a dynamic solid model.

Implicit constraints – implicit constraints are constraints which get applied automatically by the software when the user sketches lines. Examples of common implicit constraints are the horizontal and vertical constraints that are applied to lines when they are sketched.

Explicit constraints – explicit constraints are constraints which the user must apply by completing some type of command action.

Dimensional constraints – dimensional constraints are the dimensions that are applied by the user to a sketch. They define distances between two points or features.

Geometric constraints – geometric constraints are constraints that define relationships between geometric elements. For example, two lines may be defined as parallel, equal, or collinear (in the same line).

Degrees of freedom – degrees of freedom define the manner in which an object can move. Each object has six degrees of freedom; 3 translational (linear movement along the X, Y, or Z axes) and 3 rotational (rotation about the X, Y, or Z axes).

Design intent – design intent is a term used to describe how feature definitions and constraints are used to control the 2D and 3D geometry of a solid model in a predictable manner.

Bidirectional associativity – bidirectional associativity is a term used to describe the relationship between part, assembly, and drawing files within a constraint-based solid modeler. Within constraint-based modelers that have bidirectional associativity, changes to any of the files (parts, assemblies, or drawings) are automatically updated in all linked files (eg. a change to the part file automatically generates changes to the assembly and drawing files or a change to the drawing file automatically generates changes to the assembly and part files).

Unidirectional associativity – Within constraint-based modelers that have unidirectional associativity, changes to a part file automatically generate changes to assembly and drawing files, but not vice versa.

Figure 1. Files within a Constraint-Based Modeler.

UNIT C: Constraint-Based/Parametric Solid Modeling

Competency: D503.00

Demonstrate the concepts and principles of constraint-based/parametric solid modeling

Objective: D503.02

Explain the concepts related to constraint-based/parametric solid modeling

Explain the following:

Describe the procedure for modeling parts within a constraint-based CAD program.

Think about design intent. How might parts be changed later?

Define/select a construction plane or workplane to begin sketching. Use one of the default planes (Frontal, Horizontal, Profile or Front, Top, Right), select a planar surface, or construct a new plane.

Sketch the new profile.

Constrain the profile by adding geometric and dimensional constraints.

Define the feature parameters.

Extrude/Revolve/Sweep/Loft

One side/Two side

Distance

Outside/Inside

Boolean (Union, Subtract, Intersection)

Execute feature and revise if necessary

Add Repetitive Features

Mirroring features

Circular patterns/arrays

Linear or rectangular patterns/arrays

Add other features

Shell

Helix

Fillets

Chamfers

Draft

Feature tree / Browser / Modeling tree / Feature Manager Design Tree – Constraint-based or parametric modelers all have some type of modeling tree that records a history of how a part was constructed (see Figure 1). These histories usually include a combination of default construction planes, the origin, and the individual features that were put together to form the object. Features can be driven by some type of sketch (like an extruded feature), or they may be created without a sketch (fillets and chamfers).

Figure 1. Solid Model of the PLATE with its Modeling Tree.

The Base-Extrude feature in Figure 4 includes a sketch (Figure 2) and a feature definition (Figure 3). The sketch defines geometry relative to some origin or series of construction planes. The feature definition tells the software what to do with the profile created in the sketch. The user may extrude the sketch to add material, extrude the sketch to remove material, revolve the sketch about an axis to add or remove material, or have the sketch follow some defined path to add or remove material.

Figure 2. Initial Base-Extrude Sketch for the PLATE.

Figure 4. Feature Definition of the PLATE Base-Extrude.

The PLATE also includes a feature that does not require a sketch. Figure 4 illustrates a fillet feature where the edges to be filleted are selected and a fillet radius is defined. When all of the edges are combined into one fillet command, the user can change all fillets with one feature modification.

Figure 4. Fillet Feature for the PLATE.

Constraints - Another important concept for students to understand when working within constraint-based programs is how constraints work. Within a single part a constraint may be a dimension or it may define the relationship between geometric elements. In Figure 5, three dimensions or dimensional constraints are shown, but there are many geometric constraints that were applied to make sure the geometry changes correctly if the dimensions are modified. For example, tangent constraints were applied between the four arcs and their corresponding lines. An equal constraint was applied between the four arcs. The two vertical lines are symmetric about the vertical center line. The two horizontal lines are symmetric about the horizontal center line.

Figure 5. Two-Dimensional Constraints in a Sketch.

2D constraints.

Dimensional constraints –dimensions applied at the sketch level of a constraint-based modeler.

Geometric constraints – constraints that work with dimensional constraints to fully define part geometry. Fully defined geometry is located relative to the part’s origin.

i.	Vertical

ii.	Horizontal

iii.	Parallel

iv.	Perpendicular

v.	Tangency

vi.	Concentric

vii.	Collinear

viii.	Coincident

ix.	Symmetry

Implicit constraints – These are constraints that are automatically applied when the user sketches lines. Examples of common implicit constraints are the horizontal and vertical constraints that are applied to lines when they are sketched.

Explicit constraints – These are constraints that the user must apply by completed some type of command action.

2.	3D – Assembly constraints – Constraint-based or parametric modelers also allow the user to define relationships between parts in an assembly. In Figure 6, several 3D constraints were applied between parts to allow the 3D models to be moved in a manner consistent with the real design. Concentric constraints were applied between the PIN and the BUSHING, the BUSHING and the WHEEL, and the PIN and the BRACKET. A coincident constraint was applied between the top surface of the BUSHING and the top surface of the WHEEL. Constraints were applied to the rest of the parts until all desired degrees of freedom were eliminated. Each object has six degrees of freedom; 3 translational (linear movement along the X, Y, or Z axes) and 3 rotational (rotation about the X, Y, or Z axes).

Figure 6. Assembly of the DOOR GUIDE.

Examples of 3D-Assembly Constraints

a.	Coincident

b.	Concentric

c.	Distance

d.	Tangent

D.	Design Intent – By adding constraints to a sketch (such as in Figure 5), the part designer is establishing some type of design intent. In other words, if a dimension is modified, the geometry should change only in a way defined by the designer. These changes should reflect how the part works within the assembly. For the part in Figure 8, the intent is to always keep the part centered about the origin. The symmetric constraint will maintain this intent when either the 1.500 or 3.00 dimensions are modified. As parts become more complicated, the designer can build more sophisticated design intent into the model using equations (eg. one side of a sketch is always 2 times longer that an adjacent side).

E.	Parent-Child Relationships – One of the most powerful features of constraint-based or parametric modelers is the idea of parent-child relationships. These types of relationships can exist at the sketch or feature level. For example, the object in Figure 7 consists of two extruded features. The base was created first and then the cylinder was added to the top surface of the base. The top surface of the base is the parent of the sketch for the cylinder (or the sketch for the cylinder is the child of the top surface). If the height of the Base-Extrude is modified, the sketch for the cylinder moves with the top surface.

Figure 7. Parent-Child Relationships.

Other parent-child relationships can be created between geometry in two separate sketches. The part in Figure 8 was created by extruding a cylinder and then extruding a rectangle. Notice that no dimensions are added for the depth of the rectangle. The front and back edges of the rectangle are tangent to the cylinder, so changes in the diameter of the cylinder will drive the depth of the rectangle.

Figure 8. Parent-Child Relationships Between Geometry in Separate Sketches.

Geometry vs. Topology – Geometry or geometric information consists of the shape, size, and location of geometric elements. Topology or topological information is the relationship between vertices, edges, and faces. The two objects in Figure 9 have the same topology. In other words, the relationship between vertices, edges, and faces is the same for the two objects. The geometry, however, is different between the two. The objects in Figure 10 have different topology. They do not have the same number of vertices, edges, or faces.

Figure 9. Objects with the same Topology but different Geometry.

Figure 10. Objects with different Topology.

Design Tables or Family Tables - Design tables are used to create different variations of a single part. They are excellent for creating standard parts that have the same basic geometry but have multiple sizes (eg. standard bolts, nuts, keys, etc.). The idea is to create a table that drives the dimensions in the solid model. The table can be edited and the edited part regenerated to show the change. Although tables can be designed to change multiple features and dimensions, care must be used so these changes do not conflict. For this reason it is often necessary to establish constraints between geometric entities so that the integrity of the part is maintained. The example shown in Figure 11 illustrates 4 iterations of a bearing. Notice that the topology (relationships between vertices, edges, and faces) is the same for the 4 examples. The difference between the parts is only in the values of the defining dimensions of the geometry.

Figure 11. Example of a Design Table.

Associativity – Associativity is the type of relationship that exists between constraint-based CAD files (parts, assemblies, and drawings).

Bidirectional Associativity – Changes made to a part, assembly, or drawing file are automatically updated in the other two files. For example, Figure 12 shows a PLATE with a 20 millimeter diameter hole in the center. A drawing of the part is shown to the right side of the part. If the hole is changed from 20 to 15, the change is automatically updated in the drawing file.

Figure 12. Example of Bidirectional Associativity.

Unidirectional Associativity – Changes to a part file are updated in the drawing and assembly files, but changes to drawing and assembly files are not allowed to modify the linked part files. Some companies will break the link between the drawing file and the 3D model at some point to make sure a person detailing a drawing does not have the ability to change the 3D database.

Creating Assemblies. Each software will have its own distinct way to create assemblies of parts. All involve inserting individual part files and/or sub-assembly files into the final assembly and then eliminating degrees of freedom so parts move in a predictable manner.

Insert components into the assembly file. Figure 13 shows three files inserted into an assembly file: the BASE, PLATE, and HEX CAP SCREW. Usually the first file inserted into the assembly is fixed or cannot be moved.

Figure 13. Inserting Part Files into an Assembly File.

Use 3D constraints to eliminate degrees of freedom. For the parts in Figure 13, the sequence for adding 3D constraints might be as follows:

Add a Concentric constraint between the hole in the BASE and the hole in the PLATE. The PLATE can still move up and down and also spin.

Add a Distance constraint (0.01) between the top surface on the BASE and the bottom surface on the PLATE. The PLATE can only spin.

Add a Parallel constraint between the front surfaces of the BASE and PLATE. All degrees of freedom for the PLATE should now be eliminated.

Add a Concentric constraint between the hole in the PLATE and the cylindrical surface of the HEX CAP SCREW. The HEX CAP SCREW can still move up and down and also spin.

Add a Distance constraint (0.01) between the top surface of the PLATE and the bottom surface of the HEX CAP SCREW head. The HEX CAP SCREW can only spin.

UNIT C: Constraint-Based/Parametric Solid Modeling

Competency: D503.00

Demonstrate the concepts and principles of constraint-based/parametric solid modeling

Objective: D503.03

Create solid models using a constraint-based/parametric solid modeler

Requirements: Using a constraint-based modeler such as Inventor®, SolidWorks®, SolidEdge®, Pro/Engineer®, or ProDesktop®, each student is required to create 3D models of the parts in the RAISING BLOCK (see drawings below) and put them together in an assembly.

1.	Using a constraint-based modeler, create 3D models of the WEDGE BASE, WEDGE TOP, and WEDGE SCREW (use the drawings below).

2.	Using a constraint-based modeler, create an assembly of the RAISING BLOCK. Insert the parts in this order: WEDGE BASE, WEDGE TOP, and then the WEDGE SCREW. Add 3D constraints such that the parts will move in the following manner:

a.	The WEDGE BASE should not move within the assembly.

b.	The WEDGE TOP should slide along the angled surface of the WEDGE BASE just like the parts would actually function.

c.	The WEDGE SCREW should be concentric with the tapped hole on the WEDGE TOP, and the surface under the head should be coincident with the surface of the WEDGE BASE.

3.	Add your name, problem number (D503.01.001), and date as a note to the file.

4.	Time Limit = 90 minutes.

5.	An effort should be made to select an origin placement on each part that reflects design intent (how the parts will really function when manufactured).

6.	Your work should reflect an understanding of 3D constraint-based model construction, creating new construction planes or workplanes, and creating an assembly with appropriate 3D constraints.

Figure D503.03.01. Assembly of RAISING BLOCK.

Figure D503.03.02. RAISING BLOCK Parts.

Figure D503.03.03. WEDGE BASE – CAST STEEL.

Figure D503.03.03. WEDGE TOP – CAST STEEL.

Figure D503.03.03. WEDGE SCREW – SAE 4140.

Assembly taken from Spencer, H. C., Dygdon, J. T. & Novak, J. E. (2004). Basic technical drawing (8th ed.). New York: Glencoe/McGraw-Hill. p. 361. ISBN: 0-07-845748-3.

Assessment: The problem will be evaluated based on the following criteria:

Criteria	Point Range

Correctness of the WEDGE BASE model	25 points

Correctness of the WEDGE TOP model	25 points

Correctness of the WEDGE SCREW model	25 points

Correctness of the assembly	20 points

Notes	5 points

Rubric for CONSTRAINT-BASED MODELING – Create solid models using a constraint-based/parametric solid modeler – D503.03

Correctness of the WEDGE BASE model

Part is not modeled accurately. Features are missing. Origin location does not reflects the part’s design intent.	Most dimensions in the part are accurate. Most features are included. Origin location reflects the part’s design intent.	Part is modeled accurately. All features are included. Origin location reflects the part’s design intent.	Total Points
0-17 points	18-23 points	24-25 points

Correctness of the WEDGE TOP model

Part is not modeled accurately. Features are missing. Origin location does not reflects the part’s design intent.	Most dimensions in the part are accurate. Most features are included. Origin location reflects the part’s design intent.	Part is modeled accurately. All features are included. Origin location reflects the part’s design intent.	Total Points
0-17 points	18-23 points	24-25 points

Correctness of the WEDGE SCREW model

Part is not modeled accurately. Features are missing. Origin location does not reflects the part’s design intent.	Most dimensions in the part are accurate. Most features are included. Origin location reflects the part’s design intent.	Part is modeled accurately. All features are included. Origin location reflects the part’s design intent.	Total Points
0-17 points	18-23 points	24-25 points

Correctness of the assembly

Parts are not oriented correctly. No 3D constraints are present.	Parts are oriented correctly. Some 3D constraints are missing.	Parts are oriented correctly within the assembly. The 3D constraints are correct and the parts move correctly.	Total Points
0-14 points	15-18 points	19-20 points

Notes

No name or assignment information present.	Name or assignment information missing.	File saved properly. Name and assignment information attached to file properly.	Total Points
0 points	3 points	5 points

Total Score

Threads and Fasteners

004.

Construct various types of thread and fastener representations and their annotations

004.01

Specify threads and fasteners on a technical drawing

004.02

Construct an assembly drawing requiring the use of fasteners

UNIT D: Threads and Fasteners

Competency: D504.00

Construct various types of thread and fastener representations and their annotations.

Objective: D504.01

Specify threads and fasteners on a technical drawing.

Introduction:

This unit will provide the student with an understanding of the basic types of fasteners used in the assembly of parts and the method in which they are represented on a technical drawing. Even though most fasteners are considered as standard parts and need not be drawn, the CAD Operator should have the basic knowledge to select the best fastener for the best use.

Purpose of Fasteners: R1 (362), R2 (379-381), R3 (308)

Screw threads are mainly used to hold parts together, as by a bolt or screw.

Adjust parts with respect to each other, as on the adjusting screw of a drafters compass.

Transmit power, as on a wood-workers vise or an automobiles tire jack.

Apply pressure, such as the purpose of the setscrew, designed to hold an object in place with respect to another.

Thread Terminology: R1 (362-363), R2 (382), R3 (308-312)

Helix – Is the spiral grooves cut into the surface of cylinders. This is the same form made by wrapping a copper wire around a cylinder to form a spring.

External – Refers to threads found on a bolt, cap screw, wood screw, etc.

Internal – Refers to threads found on a nut or tapped inside a part.

Major Diameter – Is the largest diameter of a thread. Measured from crest to crest.

Minor Diameter – Is the smallest diameter of a thread.

Crest – Is the shallowest thread cut. It can be rounded or flat.

Root- Is the deepest thread cut. It can be rounded or flat.

Pitch – The pitch of a thread is the distance from one point on the thread to the corresponding point on the next form. The pitch of a thread is usually expressed in tables in terms of the number of threads per inch.

Lead – Is the distance a thread moves in one revolution.

Single Threads – Has a lead equal to its pitch

Multiple Threads – Has a lead equal to more than one pitch. Multiple threads permit rapid advancement of parts. For example, a double thread will advance twice as far as a single thread in one revolution.

Class of Fit – There is four standardized classes of fit. The term fit refers to how closely the screw fits in the threaded hole. That is the amount of play between the two parts.

Class 1: Loose fit, used for rough work.

Class 2: Free fit, general-purpose use of most bolts and nuts.

Class 3: Medium fit, used for the better grades of work, such in automobiles.

Class 4: Close fit, used where a very snug fit is required, as in aircraft engines.

Thread Depth – Refers to the distance from the top of the thread (crest), to the bottom of the thread (root).

Thread Angle – The angle formed by the walls of the thread. The angle created by the slope of the thread is a standard 60 degrees.

Right-Handed (RH) – Advances into a nut when turned clockwise. All threads are understood to be RH unless designated specifically LH in the thread note.

Left-Handed (LH) – Advances into a nut when turned counterclockwise.

Figure 1. Screw Thread Terms.

Thread-Cutting Tools: R1 (378), R3 (309, 316-319)

Smaller threads may be cut by hand and larger threads by a lathe.

Tap - Is a small fluted cutting tool with cutting teeth shaped to form small internal threads.

Die – Is a machine tool used to form small external threads.

American National Standard For Unified Threads: R1 (363), R2 (381-386), R3 (320)

The American National Standard Institute (ANSI) established ANSI B1.1 as the American Standard for Unified Screw Threads. It is referred to as the Unified system because it has been agreed upon by the United Kingdom and Canada as well as the United States. Unified threads are the basic American standard for fastening type screw threads. Fasteners with constant pitch threads are sized by the basic major diameter and by the number of threads per inch. These two dimensions are combined to create the various thread series.

Unified National Coarse (UNC) - Threads are the most common series.

Unified National Fine (UNF) - Threads have a greater tensile strength than UNC threads, so they fasten securely. (Tensile strength is a measure of resistance to lengthwise stress.)

Unified National Extra Fine (UNEF) - Threads have the highest tensile strength. They provide the greatest security in high vibration situations.

Metric Thread – Considered as the ISO standard for international threads. Very similar in profile to the Unified series, but the two are not interchangeable.

Square Thread – Is primarily used to transmit motion or power along the line of the screw’s axis Such as the threads on a woodworking vise. However this thread is very difficult to manufacture because of its perpendicular sides.

ACME Thread – It is a modification of the square thread, which is easier to manufacture because of its 60 degree angled form. Acme threads are popular on such designs as screw jacks, vice screws, and other machinery that requires a rapid screw action. Better known as the worm thread when used on shafts to carry power to worm gears.

Sharp-V Thread – Type of thread that will fit and sill tightly and is used where friction holding or adjusting is important. Mainly used on brass parts.

Knuckle Thread- Are used for items such as light bulbs and screw-type bottle tops.

Buttress Thread – Is used to transmit great power in one direction, as on an automobile bumper jack.

Figure 2. Screw Thread Forms.

Thread Representation: R1 (365-371), R2 (393-399), R3 (312-316)

There are three methods of thread representation in use:

Simplified Method – is the most common method of drawing thread symbols. This method is used for all forms of threads, as Unified, square, acme, etc. Many companies have adopted the simplified method because it saves time and money in the design process. Hidden lines are drawn parallel to the axis at the approximate depth of the thread. The crest line is represented by a visible line, also parallel to the axis, in viewing the major diameter of the thread.

Schematic Method – Is not as true to form as the detailed method but more in depth than the simplified method. The long thin lines represent the crest of the threads and the roots by the short thick lines, both at right angles to the shaft.

Detailed – Is the nearest approximation to the true thread picture, in which straight lines replace the helical curves. This method is very complex and timely in the development of standard parts. However may be used in drawing the larger threads if show desirer.

Figure 3. Thread Representation (External).

Conventional Practices: R1 (366), R2 (393-399), R3 (312-320)

(a) Blind Hole	(b) Through Hole

Figure 4. Simplified Method of an Internal Threaded Part.

Figure 5.(a) Tap drill hole, (b) internal thread, (c) thread depth, and (d) tap representation usually drawn at 30°. The depth of the tap is taken from the horizontal hidden line at the end of the cylinder, and not the vertex of the angle.

Thread Annotations/Specifications: R1 (372-374), R2 (385-387), R3 (319-331)

Unified Annotations - The screw thread is specified by giving its nominal (major) diameter, number of threads per inch, class of fit, and external (A) or internal (B). If the thread is to be left-hand, include the letters LH after the class symbol. The size of the thread may be given on the drawing by using either fractional-inch sizes or decimal-inch sizes.

Example: .75-10UNC-2A	.75” = Major diameter of the thread.

10 = Threads per inch.

UN = Unified threads.

C = Coarse thread.

2 = Class 2 fit.

A = External thread.

Example: .88-14UNF-2B	.88 = Major diameter of the thread.

14 = Threads per inch.

UN = Unified threads.

F = Fine thread.

2 = Class 2 fit.

B = Internal thread.

Example: .375-32UNEF-4A-LH	.375 = Major diameter of the thread.

32 = Threads per inch.

UN = Unified threads.

EF = Extra Fine thread.

4 = Class 4 fit.

A = External thread.

LH = Left-hand thread.

Metric Annotations – ISO metric screw threads are specified by its nominal size (basic major diameter) and pitch, both expressed in millimeters. Include a (M) to denote that the thread is an ISO metric screw thread. Place the unit of measure (“M” for metric) before the major diameter. Use “X” to separate the major diameter from the pitch.

Example: M10 X 1.25	M = Designates it as an ISO metric thread.

10 = Major diameter.

X = Separation between the diameter and pitch.

1.25 = Thread pitch.

Example: M10	M = Designates it as an ISO metric thread.

10 = Major diameter.

(This type annotation denotes a coarse metric thread).

Example: M10 X 1.25 X 25	M = Designates it as an ISO metric thread.

10 = Major diameter.

X = Separation between the diameter and pitch.

1.25 = Thread pitch.

X = Separation.

25 = Thread length.

Threaded Fasteners: R1 (378-391), R2 (386402), R3 (321-331)

Bolt – Is an externally threaded fastener, with a hex or square type head and designed to hold two or more parts together with a nut or threaded part.

The bolt thread length is twice the major diameter plus .25” for bolts under 6” long and twice the major diameter plus .50” for bolts over 6” long.

The thread length equals the bolt length only on short bolts.

Heavy structural hex-head bolts contain a washer-like surface as an integral part of the head. Normally .016” thick.

Hex and Square head bolts may be Unified coarse or fine series with a class 2 fit.

Bolts and nuts are identified by a thread note, length, and head type. For example, .625 -11UNC-2A X 1.50 LONG HEX HEAD

Nut – Is a bolt retainer.

Selected to match the bolts and the application needed.

They are generally classified as flat, washer faced, plain, acorn, wing, and slotted.

Designate nuts in the same matter as bolts, except the length is not required. For example: .625-11 HEX NUT.

Cap Screws – Have finished heads and are used when appearance and accuracy are important.

Cap screws have a chamfer to the depth of the first thread.

Used in the assembly of mating parts.

Typical cap screw annotation: .437-14UNC-3 X 2.25 HEX CAP SCR

Figure 6. Some Common Heads For Cap Screws Include: (a) Round, (b) Pan, (c) Oval, (d) Hex, (e) Socket, (f) Flat, and (g) Phillips.

Machine Screws – resemble cap screws but are smaller.

They are frequently used with nuts to fasten parts together.

Machine screws have no chamfers.

Machine screws are used in firearms, jigs, fixtures, and small mechanisms.

Common heads for Machine screws include flat, oval, round, fillister, truss, binding, and pan heads.

Typical cap screw annotation: .312 X 2.25 OVAL MACH SCR

Set Screws – are used to prevent relative motion, usually rotary, between two parts.

There are generally two types: square head and headless.

Because of safety issues the headless setscrew would be best for rotating parts.

Typical setscrew annotation: .500 – 13UNC-2A X 1.50 SQ HD FLAT PT SET SCR

Wood Screws – create their own thread when you drive them into soft woods such as pine and spruce.

Cone shaped shafts for easy entry into the wood.

Hard woods, such as maple or oak, may require drilling a pilot hole.

Figure 7. Some Common Heads For Wood Screws Include: (a) Round, (b) Flat Head Slotted, (c) Oval and (d) Flat Head Phillips.

Non-threaded Fasteners:	R1 (386-392), R2 (391-392), R3 (330-331)

Keys – Keys are used to prevent relative movement between, wheels, pulleys, gears, cranks, and similar parts to a shaft.

Woodruff Key – Is semicircular in shape and is often used in machine-tool work. The bottom of the key fits into a semicircular key slot cut with a Woodruff cutter and the top into a rectangular slot.

Square Key – Design is used for heavy-duty functions. Sometimes referred to as a flat key.

The widths of keys generally used are about one-fourth the shaft size.

One half of the key is sunk into the shaft.

The depth of the keyway or the keyseat is measured on the side – not the center.

Gib Head Key – It is exactly the same as the square key except that it has a gib head, which provides for easy removal.

Pratt & Whitney Key – Is rectangle in shape with semi-cylindrical ends.

Figure 8. Key Types.

Pins – can be classified under two separate groups. One, which allows the assembly of parts that, might require the need for quick release. The other use as semi-permanent fasteners, design with an interference fit that would require the aid of tools for installation or removal. The following basic design rules should be followed:

The need for disassembly of parts by hand or tools.

Pins are usually designed for light work.

Use where appearance is not critical (pins need to protrude).

Type of machine pin to use.

Figure 9. Most Common Types Are: (a) Clevis Pin, (b) Straight Pin, (c) Taper Pin, and (d) Cotter Pin.

Rivets – are regarded as permanent fasteners.

Generally used to hold sheet metal or rolled steel shapes together.

The shaft of the rivet is inserted into the aligned holes of the matting parts and then formed to create a head on the opposite end of the shaft, establishing a permanent assembly.

Figure 10. Rivet (a) Before Installation, (b) Installed.

CAD Techniques: R1 (376-377), R2 (403-409)

Symbol Library – Is a drawing file that contains a larger number of commonly used (standard) items, saved as W-blocks (in AutoCAD) that you can use in other drawing files.

From a fastener symbol library, you can select the appropriate fastener; insert it into the drawing at the appropriate size and orientation.

There are three ways to incorporate standard fasteners from symbol libraries into your drawings:

Create your own symbol library. Since the bolt drawing saved as 1-hex-bolt.dwg (in the “Drawing Bolts and Nuts” Task Sheet exercise, included with this unit) was drawn with a major diameter of one inch, it could be transformed into a BLOCK, then insert it into the drawing file at any specified size. Meaning that you will have one master bolt and nut drawing to fit all sizes. For example, for a bolt with a major thread diameter of .75 inches, the scale for insertion would be set to: X= .75, Y= .75. The bolt would be inserted with a major diameter of .75 inches. Explode the block to adjust (stretch) the length of the thread and bolt length and adjust the line type scale. The bolt head and nut will automatically be in the proper proportion with the major diameter specified. Convert the block into a WBLOCK so that it can be used with other files for future use.

Most CAD systems are supplied with libraries or sample files that contain fasteners that can be inserted (AutoCAD Inventor 8/9 standards library and/or AutoCAD 2000-2005 and LT versions can refer to the Design Center),

Purchase a third party symbol library.

TASK SHEET D504.01.01

Drawing Threads by the Simplified Method

The following procedure will illustrate the step-by-step techniques in drawing the external and internal threaded parts with CAD.

The external thread specification for this example is: 1-8UNC-2A and 2B.

STEP 1

Start your CAD system and begin a new drawing. Set units to decimal with a precision of four decimal places. Set the drawing limits for “A” size paper (11” x 8.5”).

Develop the following layers:

LAYER NAME	COLOR	LINETYPE	LINEWEIGHT
Visible	Magenta	Continuous	.028
Hidden	Yellow	Hidden2	.014
Center	Red	Center2	.010

Make the CENTER layer current and draw a horizontal and vertical centerline as shown in Figure 1. Make the horizontal line 8” long and the vertical line 3” long.

Figure 1. Step 1.

STEP 2

Make the VISIBLE layer current. Draw a 2” square around the intersection of the horizontal and vertical centerlines. This represents the part in which the internal thread will be created. Draw a circle with the diameter of the minor diameter (Refer to Figure 3. Table 1).

Figure 2. Step 2.

Table 1 - Unified Coarse Threaded Series, UNC

NOMINAL SIZE	THREADS PER INCH	MAJOR DIAMETER	MINOR DIAMETER	PITCH DIAMETER	TAP DRILL 75%
1/4	20	0.2500	0.1875	0.2175	7.0000
5/16	18	0.3125	0.2403	0.2764	F
3/8	16	0.3750	0.2938	0.3344	0.3125
7/16	14	0.4375	0.3447	0.3911	U
1/2	13	0.5000	0.4001	0.4500	0.4219
9/16	12	0.5625	0.4542	0.5084	0.4844
5/8	11	0.6250	0.5069	0.5660	0.5313
3/4	10	0.7500	0.6201	0.6850	0.6563
7/8	9	0.8750	0.7307	0.8028	0.7656
1	8	1.0000	0.8376	0.9188	0.8750
1 1/8	7	1.1250	0.9394	1.0322	0.9844
1 1/4	7	1.2500	1.0644	1.1572	1.1094
1 1/2	6	1.5000	1.2835	1.3917	1.3438

Figure 3. Table 1.

Note: To approximate the thread depth, subtract the tap drill diameter (found in the chart above) from the major diameter, and divide by 2.

Example Thread Specification: 1.125-7UNC. According to the chart above, the tap drill diameter is .9844

Solution: (1.125 - .9844) ÷ 2 = .0703

STEP 3

Make the HIDDEN layer current and draw another circle concentric to the previous circle, with a diameter of 1” (major diameter of the external thread.)

Figure 4. Step 3.

STEP 4

Make the VISIBLE layer current. Project a horizontal line to the left, from the top quadrant of the 1” diameter circle, parallel to the end of the centerline. Now offset this line 1” below the centerline. Draw a vertical line 1” to the left of the 2” square to connect the two horizontal visible lines. Trim the visible lines to the right of the vertical line. This will represent the external threaded part. Make the HIDDEN layer current. Draw the hidden lines on the external part as shown in Figure 5 to represent the minor diameter of the thread.

Figure 5. Step 4.

STEP 5

Chamfer the right end of the external part equal to the offset distance of the hidden and visible horizontal lines.

Figure 6. Step 5.

STEP 6

Construct a conventional break for a solid shaft on the left end of the external part.

Display the thread notes with a leader command for the external thread. Display the internal thread note using the dimension diameter leader and override the text with the MTEXT command. This will allow the arrowhead of the leader to point directly toward the center of the circle as shown in Figure 7. Save the drawing with the name: SIMPLIFIED.dwg. Plot or print a hardcopy of the threads for your instructor.

Figure 7. Step 6.

TASK SHEET D504.01.01

Drawing Bolts and Nuts

To draw a hexagonal headed bolt and nut follow the procedures below. The same procedure is followed whether the bolt or nut is to have a square or hexagonal head. The thread specification for this example is: 1-8UNC-2A X 1.50 LONG HEX HEAD.

Information needed to complete the drawing of a bolt and nut:

Bolt diameter

Bolt length

Type of head and nut.

Figure 1. Bolt and Nut Terms.

The dimensions given in Figure 2 are approximations but are acceptable for most drafting applications.

Bolt & Nut Formulas:

D = Major Thread n.

H = 2/3 D.

T = 7/8 D.

W = 1-1/2 D.

Figure 2. Bolt & Nut Formulas.

STEP 1

Start your CAD system and begin a new drawing. Set units to decimal with a precision of four decimal places. Set the drawing limits for “A” size paper (11” x 8.5”). Develop the following layers:

LAYER NAME	COLOR	LINETYPE	LINEWEIGHT
Visible	Magenta	Continuous	.028
Hidden	Yellow	Hidden2	.014
Center	Red	Center2	.010

Make the CENTER layer current and draw horizontal and vertical centerlines as shown in Figure 3.

Figure 3. Step 1.

STEP 2

Make the VISIBLE layer current, and draw a circle with a radius equal to 1.5 X the major diameter of the thread. Circumscribed a hexagon around the circle. Rotate the hexagon to the proper rotation as shown in Figure 4. This forms the end view for the head of the bolt.

Figure 4. Step 2.

STEP 3

With Ortho mode on, project construction lines from each vertex of the hexagon to establish placement of the horizontal lines needed to construct the front view of the bolt head. Draw a vertical line, approximately 1.00” to the left of the hexagon, across the projected horizontal lines. Offset the vertical line to the left equal distance to 2/3 of the major diameter of the bolt. Trim the front view of the head to match Figure 5.

Figure 5. Step 3.

STEP 4

To establish the bolt head chamfers, draw one line at an angle of 150 degrees from, approximately 3” long, from the intersection of the lower right corner of the bolt head. Draw another construction line, which is to intersect the first construction line, at an angle of -150 degrees, approximately 3” long from the upper right corner of the bolt head. See Figure 6.

Figure 6. Step 4.

STEP 5

From the intersection of the two construction lines, create a circle with a radius tangent to the topside of the bolt head. Trim the circle to match Figure 7.

Figure 7. Step 5.

STEP 6

Connect a vertical construction line through the intersection of the arc end points and the bolt head corners. Extend both end points of the construction line to the outer edges of the bolt head as in Figure 8. Draw two circles using the 3-point method. Use the intersection of the construction line as the first point, the tangent point of the top surface of the bolt head for the second point, and the end point of the previous drawn arc (in step 7) for the third point. Repeat the process for the other side. See Figure 8.

Figure 8. Step 6. Hint: use object snaps endpoint, tangent, and intersection with the 3-point circle.

STEP 7

Trim the two circles and erase all construction lines. Offset the bottom of the hex head .016” into the head and trim to create the washer-like surface. See Figure 9.

Figure 9. Step 7.

STEP 8

To create the bolt shaft with the simplified threads, follow the directions from the exercise, “Drawing Threads by the Simplified Method”.

STEP 9

The bolt thread length is twice the major diameter plus .25” for bolts under 6” long and twice the major diameter plus .50” for bolts over 6” long. The thread length for the 4” long bolt, with a major diameter of 1.00”, will be 2.25” long.

STEP 10

To create the nut, mirror the hex head onto the shaft. Then use the stretch command to increase the thickness of the hex nut to equal .875” X the major diameter of the thread. Add the washer face as you did for the hex head. Save the drawing as a 1-hex-bolt.dwg. Plot or print a hardcopy of the threads for your instructor.

Figure 10. Step 10.

UNIT D: Threads and Fasteners

Performance Test D504.02.01

Competency: D504.00

Construct various types of thread and fastener representations and their annotations.

Objective: D504.02.01

Construct an assembly drawing requiring the use of fasteners.

Requirement:

Using the equipment provided, construct a full sectional view assembly of the Coupling, shown on the following page. Show all bolts, nuts, key, keyseat, and keyway as required.

When plotted the drawing should fit on a size A (8.5” X 11”) sheet of paper at a scale of 1:1.

Center the drawing within the working area of the borders. Layout to be assigned by the test Administrator.

Letter your name, problem number (D504.02.01), scale, and date in the title block, as assigned by the test Administrator.

Save your work on the diskette provided or as directed by the test Administrator.

Time Limit = 90 minutes.

Your drawing will be evaluated on its accuracy and completeness.

Dimensions may be omitted. However apply local notes for bolt and key sizes according to ANSI standards.

Use the following specifications for drawing set-up:

Units = decimal

Limits = size A paper (11” X 8.5” landscape)

Layers = as shown in the chart below.

LAYER NAME	COLOR	LINETYPE	LINEWEIGHT
Visible	Magenta	Continuous	.028
Hidden	Yellow	Hidden2	.014
Center	Red	Center2	.010
Dimension	Green	Continuous	.010

Assessment: The 2D CAD drawing should be evaluated based on the following criteria:

Criteria	Point Range

CAD Set-up	20 points

Accuracy	25 points

Line and Feature Representation	25 points

Dimensioning and General Annotations	25 points

Layout and Title Block Information	5 points

UNIT D: Threads and Fasteners

Performance Test D504.02.01

EXPLODED ASSEMBLY	ASSEMBLY
Rubric for Threads and Fasteners – Construct an assembly drawing requiring the use of fasteners – D504.02.

CAD Setup

Numerous errors in setting up layers, limits, units, colors, line weight, and line types.	Some errors in setting up layers, limits, units, colors, line weight, and line types.	Layers, limits, units, colors, line weight, and line types are constructed according to specifications.	Total Points
0-14 points	15-18 points	19-20 points

Accuracy

Numerous errors in measurements.	Some errors in measurements.	When measured, the sizes of features and their locations agree with the given problem.	Total Points
0-17 points	18-23 points	24-25 points

Feature Representation

Numerous errors in the illustration of threads, bolt head and nut representation, and key design.	Some errors in the illustration of threads, bolt head and nut representation, and/or key design.	The illustration of the simplified threads, bolt head and nut representation, and key design are all according to standards.	Total Points
0-17 points	18-23 points	24-25 points

Dimensioning and General Annotations

Dimensions and text styles and text size do not meet accepted standards. Misplaced or missing dimensions and/or general notes.	Some errors in dimensioning techniques and text. No more than one spelling error.	Dimensions, text styles, text size, and spelling meet standards according to ANSI.	Total Points
0-14 points	15-18 points	19-20 points

Layout and Balance

The drawing is extremely out of balance and is very difficult to interpret.	The drawing is to some extent out of balance and could be better oriented within the working area.	The drawing is reasonably balance within the working area and very simple to read.	Total Points
0 points	3 points	5 points

Title Block Information

Majority of the information given is incorrect and some spelling errors were noted.	Most of the information is correct with no more than one spelling error noted.	All of the required information is correct and properly spelled.	Total Points
0 points	3 points	5 points

Total Score

Answer key for Threads and Fasteners – Construct a 2D CAD drawing requiring the use of fasteners.

Working Drawings

005.

Demonstrate working drawing principles and techniques

005.01

Explain the concepts and principles underlying the creation of detail drawings

005.02

Explain the concepts and principles underlying the creation of assembly drawings

005.03

Interpret information on a working drawing

005.04

Construct working drawings

UNIT E: Working Drawings

Competency: D505.00

Demonstrate working drawing principles and techniques.

Objective: D505.01

Explain the concepts and principles underlying the creation of detailed drawings.

Introduction: The purpose of this unit is to show that working drawings give all the information needed to manufacture or build a single part or a complete machine or structure.

Working drawings must be complete and clear, and they must conform to drafting standards.

Knowledge of the design requirements, manufacturing processes, and drafting practices on the part of the design and drafting team is critical. Working drawings normally include detail and assembly drawings.

Trade and industry conforms to the drafting standards set by ASME and ISO; however, it is important to note that some companies have created their own software and additional standards for personal drawing needs. While it is impossible to explain all formats that companies use, it is imperative for the drafter to recognize the differences.

(BTD 335-350, TD 411-423)

Explain the following:

Detailed drawings are production drawings that show necessary views, dimensions, and notes required to make a part without the use of additional information.

Number of details per sheet.

All details can be placed on individual sheets.

When large or complicated mechanisms are represented, the details may be drawn on several sheets with several details to a sheet.

If the structure is small or composed of few parts, all details can be drawn on one sheet.

C. Drawing standards for details

Attention should first be given to spacing.

The same scale should be used for all details.

Each detail should be represented by the regular views, sections, or auxiliaries needed to describe the part clearly.

Must have all dimensions and notes.

All parts must be identified or drawn with the exception of standard parts.

D. Identifying parts.

The old method is to letter a title note under each detail, which would then be circled or underlined.

The new method is to give a parts list or bill of materials.

A bill of materials or parts list consists of an itemized list of the several parts of a structure shown on the drawing. When numerous parts are used, the list can be given on a separate sheet.

Lists part number, title, material, and quantity required.

May include pattern numbers, stock sizes, and weights.

The parts list is located above the title block reading upward or in the upper right corner reading downward.

Parts should be listed in general order of size or importance of details.

Standard parts should be listed even when they are not drawn.

Every drawing should have a title strip or title block to show in an organized way all necessary information not shown on the drawing itself. The title strip should contain but is not limited to the following:

Name of the object represented.

Name and address of the manufacturer.

Name and address of the purchasing company, if any.

Signature of the drafter that made the drawing and the date of completion.

Signature of the checker and date of completion.

Signature of the chief drafter, chief engineer, or other official, and the date of approval.

Scale of the drawing.

Number of the drawing.

Drawing numbers.

Every drawing should be numbered.

It is advisable to use simple serial numbers, but varies from industry to industry.

It is advisable to avoid using drawing numbers to convey other information; however some companies place a prefix such as A, B, C, or D in front of the number to denote the sheet size.

The drawing number is usually the number of the part itself.

The drawing number is bold, ¼” high, and located in the lower right and upper left corner of the sheet.

When a drawing is completed it is turned over to the checker. It is checked for soundness of design, correct views, complete dimensioning, legibility, clearances, materials, standard parts, and title block information.

Change records.

A change strip or revision strip is included at some convenient place on the drawing.

In the change strip, the change is briefly described, initialed, and dated.

The change is labeled on the drawing usually by an encircled letter.

UNIT E: Working Drawings

Competency: D505.00

Demonstrate working drawing principles and techniques.

Objective: D505.02

Explain the concepts and principles underlying the creation of assembly drawings.

Explain the following:

A. Assembly drawings guide workers in assembling parts properly and for general reference throughout the shops.

Assembly drawings show the assembled machine or structure, with all detail parts in their functional positions.

In selecting views for an assembly drawing, the drafter must keep in mind the purpose of the drawing, which is to show how the parts fit together and to suggest the function of the entire unit.

The assembly should not describe the shapes of individual parts.

The views selected should be the minimum views or partial views that will show how the parts fit together.

A subassembly is used with large or complicated machines when it is not possible to show all parts in one assembly and a separate drawing is needed.

Title strips are the same for an assembly drawing as a detail drawing except for the addition of the word assembly in the title.

A parts list may be placed on a separate sheet or in any convenient open corner on the drawing. It is preferred to be read up from the title block or down from the upper right corner.

The parts list includes the part number, name, material, and number of pieces required.

Each part is identified on the drawing by lettering the part numbers in .438 or .500 diameter circles near the assembly, and drawing leaders to each part where it is clearly shown.

The circles should be arranged in groups and in vertical or horizontal rows.

Assembly sections.

In an assembly drawing where several adjacent parts are sectioned, it is necessary to draw the section lines in different directions to distinguish the pieces clearly.

The first large area is section-lined at 45o .

The next large area is then section-lined at 45o in the opposite direction.

Additional areas are section-lined at 30o or 60o with horizontal.

If necessary, to make any area contrast with the others, any other angle may be used.

Section lines do not meet at the visible lines separating the areas.

For small areas the lines are drawn closer together.

In sectioning very thin parts, when there is not enough space for section lining, the sectioned parts may be shown solid.

It is customary not to section parts that would make the drawing less clear, such as bolts, nuts, shafts, keys, ribs, gear teeth, spokes, screws, nails, ball and roller bearings, and pins.

Design assemblies or layouts.

1. One of the initial drawings created by the designer, usually drawn to full scale to enable the designer to visualize the part more clearly.

2.	Includes the views necessary to show the size and shape of each part of the mechanism, but dimensions are omitted.

Outline assembly or installation assembly

1. The purpose is to give general information regarding the character and size of the unit and how it fits in its environment.

2. In an outline assembly there is little or no section lining.

3. Only the principal overall and center-to-center distances needed to clarify questions of installation are given.

4. Outline assemblies are sometimes referred to as exploded assemblies.

Working drawing assembly

A working drawing assembly combines detail and assembly drawings giving complete dimensions and notes for all parts.

Used in place of separate detail and assembly drawings for simple parts.

General assembly

1. Shows how the part fits together and how the assembly functions.

2. Chief use is in the assembly shop where all finished parts are received and put together.

3. Views shown may be regular, sections, auxiliary, and partial.

No dimensions are usually given on a general assembly.

UNIT E: Working Drawings

Competency: D505.00

Demonstrate working drawing principles and techniques.

Objective: D505.03

Interpret information on a working drawing.

Explain the following:

Approaching the print.

Analyze the title block.

Figure D505.03.01 Example of a title block

A-Revision strip, B-name and address of the manufacturer, C-Notes and tolerances not specified on the drawing, D- Drawing standard, E- Scale of the drawing, F- Material description of the part, G- Part name, H- Personal privacy statement, I- Name of drafter, J Number of sheet, K- Date drafter completed drawing, L- Part number, M- Name of checker, N- Date drawing was checked

Determine the language of the print, and whether it is drawn in first-angle projection or third-angle projection. The standard can be written in the title block or shown as a symbol.

First-Angle Projection	Third-Angle Projection

Figure D505.03.02 Symbols for projection

Clarify which views are seen on the drawing.

Determine placement of the regular views.

Determine cutting plane lines and corresponding section views.

Determine detail size and descriptions.

Details should be labeled by a phantom line circle on the drawing where they occur.

Details can be placed in any convenient space on the drawing. Under the separated detail should be the name and scale of the detail.

Figure D505.03.03 Examples of details on a drawing

Examine all notes within the title block and on the drawing.

General notes may be given in any convenient open space on the drawing.

Local notes can be indicated through use of a leader or a bubble.

Figure D505.03.04 Examples of notes on a drawing

Locate datums and reference dimensions.

Decipher line types, dimensions, symbols, and abbreviations.

A complete list of abbreviations used on engineering drawings can be found in ANSI Y 1.1

Table 00X.03.01	Commonly Used Abbreviations

ALLOW-Allowance

ALUM-Aluminum

ALY-Alloy

ANL-Anneal

APPD-Approved

APPROX-Approximate

ASSY-Assembly

AUX-Auxiliary

B/M-Bill of Materials

BEV-Bevel

BRG-Bearing

BRKT-Bracket

BRS-Brass

BRZ-Bronze

BUSH-Bushing

C TO C-Center to Center

C’BORE-Counterbore

C’SINK-Countersink

CDS-Cold Drawn Steel

CH-Case Harden

CHAM-Chamfer

CI-Cast Iron

CL-Clearance

CONC-Concentric

COND-Condition

COP-Copper

CRS-Cold Rolled Steel

CSTG-Casting

CYL-Cylinder

DAT-Datum

DCN-Drawing Change Notice

DIA-Diameter

DWG-Drawing

EA-Each

ECO-Engineering Change Order

ECR-Engineering Change Revision

EQ-Equal

ES-Engineering Specifications

EST-Estimate

FAB-Fabricate

FAO-Finish All Over

FIL-Fillet

FIN-Finish

FORG-Forging

FST-Forged Steel

GA-Gage

GALV-Galvanized

GRD-Grind

GSKT-Gasket

HCS-High Carbon Steel

HEX-Hexagon

HOR-Horizontal

HT TR-Heat Treat

ID-Inside Diameter

INSTL-Installation

KWY-Keyway

LH-Left Hand

MACH-Machine

MAG-Magnesium

MATL-Material

MAX-Maximum

MI-Malleable Iron

MIN-Minimum

MISC-Miscellaneous

MOD-Modification

NO.-Number

NOM-Nominal

NTS-Not To Scale

OD-Outside Diameter

P-Pitch

PROC-Process

QTY-Quantity

QUAL-Quality

R-Radius

REF-Reference

REQD-Required

REV-Revision

RH-Right Hand

RIV-Rivet

SCH-Schedule

SCR-Screw

SECT-Section

SF-Spotface

SH-Sheet

SPEC-Specification

SPL-Special

SQ-Square

SST-Stainless Steel

STD-Standard

STL-Steel

SYM-Symmetrical

TEM-Temper

THD-Thread

TOL-Tolerance

TYP-Typical

VAR-Variable

VERT-Vertical

W-Width

WI-Wrought Iron

WT-Weight

TASK SHEET: D505.01

Print Reading for Comprehension

Cap Block Quiz

Study print 505.01. The answers to the questions can be found within the print.

_____________

_____________

_____________

______________________________________________________________________________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

What is the distance between the centers of the two counterbored holes?

What is the part number?

What is the tolerance on dimensions with significant digits of two decimal places?

What type of material is the part?

How many revisions required an engineering change order?

What is the maximum width of the part?

What scale is the print?

What is the first revision, and when was it made?

What is the basic size of the large hole?

How many holes have a counterbore?

What is the maximum distance the two small holes can be spaced from one another?

How many corners have been rounded?

What is the depth of the counterbore?

What is the minimum depth of the part?

How many checkers signed off on the print?

What is the maximum distance from the top side of the part to the center of the large hole?

What tolerance is allowed of three significant digit dimensions?

What is revision C?

What is the lower limit of the width dimension?

What is the diameter of the counterbore?

Print D505.01

TASK SHEET: D505.01 KEY

Print Reading for Comprehension

Cap Block Quiz

.74

A426575

.010

Cold Rolled Steel

2

2.875

1:1, Full

Remove sharp edge, made 9-12

.7395

2

.75

4

.100

.234

1

.70

.005

Width changed from 2.955 to 2.875

2.945 2.865

2.865

.380

TASK SHEET: D505.02

Print Reading for Comprehension

Rear Packing Gland Quiz

Study print 505.02. The answers to the questions can be found within the print.

_____________

_____________

_____________

______________________________________________________________________________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

_____________

What is the diameter of the large cylinder?

How many drawings are there in this particular set?

From the finish box, what does FAO mean?

What type of material is the part?

What is the part name?

What does the arrow at the top of the front view signify?

What scale is the print?

What is the first revision and when was it made?

What was the previous distance between the centers of the two countersink holes?

What is the overall width of the part?

What is the minimum distance between the center of the lower small hole and the center of the part?

To what radius should the rounded corners be machined?

What is the maximum depth of the part?

From the front view, what is the diameter of the cylinder opening?

When was the print approved?

Where is the part number located?

What should be removed before this part is complete?

What type of section is found on this drawing?

What is the countersink diameter?

What is the overall height of the part?

Print D505.02

TASK SHEET: D505.02

Print Reading for Comprehension

Rear Packing Gland Quiz

2.75

8

Finish All Over

Aluminum Casting

Rear Packing Gland

The line of sight for the section view

1=1

Degree of countersink angle has changed from 78 to 82 on 8/2

3.88

1.87

1.99

.125

1.76

2.00

7/28

Lower right hand corner of the title block

All sharp edges, burrs, and flash

Half section

.75

5.76

UNIT E: Working Drawings

Competency: D505.00

Demonstrate working drawing principles and techniques.

Objective: D505.04

Construct working drawings.

Requirements: Each student is required to complete a set of working drawings.

1.	Study the print carefully. Dimensions for mating parts are implied from one part to another.

2.	Using the drafting software provided, make a solid model of each part.

3.	From the models, produce an assembly drawing of the structure. The assembly and parts list should be on one sheet. Each part should be labeled clearly following drafting standards.

4.	The parts list should identify each part including standard parts. Include the material description, quantity, and part number.

5.	In the assembly titleblock, include name, date, institution, scale, sheet number, drawing number (D505.04.001), and the word ‘ASSEMBLY’.

6.	From the models, produce a detailed drawing of each custom part. The detailed drawings should include all necessary views to fully describe the part. Include all missing dimensions and notes.

7.	In the detailed drawings title blocks, include name, date, institution, material description, scale, part numbers, and sheet numbers. Instructor can add tolerances at their discretion.

8.	All detailed drawings should be completed at a scale of 1:1 (full size). The assembly drawing should be completed 1:2 (half size).

9.	Time Limit = 180 minutes.

10.	An effort should be made to create a balanced appearance in spacing. Place only one detail per sheet, except in assembly.

11.	Your work should reflect an understanding of working drawing concepts and principles. The views, dimensions, title strips, and parts list must conform to drafting standards. You will be evaluated on accuracy, completeness, and clarity.

Assessment: The problem will be evaluated based on the following criteria:

Criteria	Point Range

Accurate perception of a detailed print	10 points

Concepts and principles of assembly drawings	50 points

Concepts and principles of detailed drawings	20 points

Layout and balance	10 points

Complete and clear identification of all parts	10 points

Rubric for Working Drawings – Construct working drawings – D505.04.01

Accurate perception of a detailed print

Student does not comprehend the language of the print. The student needs help deciphering several notes, dimensions, and views and does not visualize the parts as a structure.	Student has some difficulty understanding the notes, dimensions, views and part placement in order to reproduce a model properly.	All dimensions, notes, and views are read correctly and the structure is reproduced accurately. Student demonstrates an understanding of how parts will fit together.	Total Points
0-6 points	7-9 points	10 points

Concepts and principles of assembly drawings

One or more views may be missing or inappropriately drawn. Impossible to see the structure clearly.	All views are displayed, but may not be clear on how the parts are assembled.	Assembly shows how all custom and standard parts fit together. All views are correctly displayed. All parts are center-to-center.	Total Points
0-37 points	38-43 points	44-50 points

Concepts and principles of detailed drawings

Regular views are absent or misplaced. Section views have been left out. Dimensions and notes do not completely describe the part.	Features are aligned and appropriate views are shown for each part. Some visible, hidden or section lines may be absent or misplaced. All dimensions are present, but may be disorderly.	Each custom part is represented by appropriately aligned regular and section views and correctly describes the shape of the object. All notes, size, and location dimensions are displayed completely and clearly.	Total Points
0-13 points	14-16 points	17-20 points

Layout and title block

Drawing layout is too congested to be clear. Title block is incomplete and does not conform to drafting standards.	Views, dimensions, and notes are crowded, but readable. Title block has correct form but missing information.	All parts are spaced appropriately to have enough room for views, dimensioning, and notes. Title block is complete with appropriate information displayed in correct form.	Total Points
0-6 points	7-9 points	10 points

Complete and clear identification of all parts

The parts list and labeling on drawing is incomplete and does not follow drafting standards.	The parts list is complete, but not appropriately labeled. Labeling on the drawing is complete but does not follow standards. The parts list is located in an inappropriate location.	The parts list follows drafting standards. The list displays all appropriate information and parts are listed in order of size and importance. The parts are appropriately labeled on the drawing.	Total Points
0-6 points	7-9 points	10 points

Total Score

Basic Geometric Dimensioning and Tolerancing

006.

Demonstrate basic geometric dimensioning and tolerancing techniques

006.01

Explain geometric dimensioning and tolerancing terms and techniques

006.02

Construct a drawing with geometric dimensions and tolerances

UNIT F: Geometric Dimensioning & Tolerancing

Competency: D506.00

Demonstrate basic geometric dimensioning and tolerancing techniques

Objective: D506.01

Explain geometric dimensioning and tolerancing terms and techniques

Introduction: The purpose of this unit is to give an introduction to the topic of geometric dimensioning and tolerancing. With the increase of interchangeable manufacturing where companies are producing parts all over the world, it is necessary to produce drawings where nothing is left to interpretation. Geometric dimensioning and tolerancing, when applied appropriately, leaves little room for interpretation. It allows for consistency between design, manufacturing, and inspection. The standard that specifies correct practices for dimensioning and tolerancing is ASME Y14.5M. This unit will cover terminology used in geometric dimensioning and tolerancing, method for reading feature control frames, datum reference frame theory, and explanations of each geometric characteristic.

Explain the following:

Geometric Dimensioning and Tolerancing is a three-dimensional, mathematical system. Within this system, features on an object are oriented or located relative to a Cartesian Coordinate System or Datum Reference Frame. This is done using Feature Control Frames, which specify acceptable tolerance zones for the features relative to the Datum Reference Frame.

Explain the following terms related to the Datum Reference Frame:

Datum Reference Frame - Sufficient datum features, those most important to the design of a part, or designated portions of these features are chosen to position the part in relation to a set of three mutually perpendicular planes, jointly called a datum reference frame. The datum reference frame exists in theory only and not on the part: R2(250-251), R3(200-204).

Figure 1. Datum Reference Frame.

2.	Datum - A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specified datum feature. A datum is the origin from which the location or geometric characteristics of features of a part are established.

3.	Datum feature - An actual feature of a part that is used to establish a datum.

4.	Datum Feature Symbol - The datum feature symbol is the symbolic means of indicating a datum feature and consists of a capital letter enclosed in a square frame and a leader line extending from the frame to the concerned feature, terminating with a triangle.

a.	Applying a feature control frame to a feature without size such as a surface.

Figure 2. Applying a Feature Control Frame to a Feature Without Size.

b.	Applying a feature control frame to a feature of size such as a hole, cylinder or slot. Datum B is the axis of the .498-.500 hole, datum C is the median plane of the .375-.380 slot, and datum D is the axis of the .997-1.000 cylinder.

Figure 3. Applying a Feature Control Frame to a Feature With Size.

5.	Datum feature simulator - A surface of adequately precise form contacting the datum feature(s) and used to establish the simulated datum(s). Typically this surface must be at least 10 times better in quality (flatness) than the tolerances specified on the drawing.

Figure 4. Datum Terminology.

4.	Feature - The general term applied to a physical portion of a part, such as a surface, pin, tab, hole, or slot.

Feature of size (feature with size) - A feature of size is a cylindrical or spherical surface, or a set of two opposed elements or opposed parallel surfaces, associated with a size dimension.

Feature without size - Typically this is a planar surface.

Types of Geometric Tolerances. A Geometric tolerance is the maximum permissible variation of form, profile, orientation, location, and runout from that indicated or specified on the drawing R1(340), R2(250).

Identify and describe the following:

Straightness - Form tolerance where an element of a surface or a centerline is a straight line. Each longitudinal element on the surface must lie between two parallel lines. The shape of the tolerance zone is a 2D area between two parallel lines. R1(346-347), R2(253).

Figure 5. Straightness.

Flatness - Form tolerance in which all surface elements are in one plane. All points on the surface must lie between two parallel planes. The shape of the tolerance zone is a 3D area between two parallel planes. R1(346-347), R2(255).

Figure 6. Flatness.

Circularity (Roundness) - Form tolerance specifying a tolerance zone bounded by two concentric circles within which each circular element of a surface must lie. All points on the surface must lie between two concentric circles. The shape of the tolerance zone is a 2D area between two concentric circles. R1(346-347), R2(253-254).

Figure 7. Circularity.

Cylindricity - Form tolerance of a surface of revolution in which all points of the surface are equidistant from a common axis. All points on the surface must lie between two concentric cylinders. The shape of the tolerance zone is a 3D area between two concentric cylinders. R1(346-347), R2(255-256).

Figure 8. Cylindricity.

Profile - A profile tolerance is the outline of an object in a given plane. Profiles are formed by projecting a three-dimensional figure onto a plane or by taking cross sections through the figure. R1(346-348), R2(253-256).

Profile of a Line - Each point on the specified path must lie between two parallel contours. The shape of the tolerance zone is a 2D area between the two contours. Perfect geometry is located with basic dimensions.

Figure 9. Profile of a Line.

Profile of a Surface - Each point on the surface must lay between two parallel/ concentric contours. The shape of the tolerance zone is a 3D area between the two contours. Perfect geometry is located with basic dimensions.

Figure 10. Profile of a Surface.

Parallelism - Orientation tolerance of a surface or center plane, equidistant at all points from a datum plane; or an axis, equidistant along its length from one or more datum planes or a datum axis. All points on the surface must lie between two parallel planes. The shape of the tolerance zone is a 3D area between two parallel planes. R1(349), R2(255).

Figure 11. Parallelism.

Angularity - Orientation tolerance of a surface, center plane, or axis at a specified angle (other than 90º) from a datum plane or axis. All points on the surface must lie between two parallel planes. Perfect geometry is located using basic dimensions. The shape of the tolerance zone is a 3D area between two parallel planes. R1(349), R2(255-256).

Figure 12. Angularity.

Perpendicularity - Orientation tolerance of a surface, center plane, or axis at a right angle to a datum plane or axis. All points on the surface must lie between two parallel planes. The shape of the tolerance zone is a 3D area between two parallel planes. R1(349-350), R2(255-256).

Figure 13. Perpendicularity.

Runout - Runout is a composite tolerance used to control the functional relationship of one or more features of a part to a datum axis. R2(253-256).

Circular Runout - All points on the surface must lie between two concentric circles relative to the datum feature. The shape of the tolerance zone is the 2D area between the two concentric circles.

Figure 14. Circular Runout.

Total Runout - All points on the surface must lie between two concentric cylinders relative to the datum feature. The shape of the tolerance zone is the 3D area between the two concentric cylinders.

Figure 15. Total Runout.

Concentricity - Location tolerance where the median points of all diametrically opposed elements of a figure of revolution are congruent with the axis of a datum feature. All points on the axis must lie within a cylinder relative to the datum axis. The shape of the tolerance zone is a 3D area within the cylinder. R1(351), R2(257-259).

Figure 16. Concentricity.

Position - Location tolerance which defines a zone within which the center, axis, or center plane of a feature of size is permitted to vary from a true position. All points on the axis must lie within a cylinder. The cylinder is located with basic dimensions from the datums. The shape of the tolerance zone is a 3D area within the cylinder. R1(342-346), R2(257-259-Figure in book is incorrect).

Figure 17. Position.

Define the following terms:

Basic Dimension - A numerical value used to describe the theoretically exact size, profile, orientation, or location of a feature or datum target. Basic dimensions are enclosed within a rectangular frame. R1(341).

Material Condition Modifiers R1(344-346).

Maximum material condition - The condition in which a feature of size contains the maximum amount of material within the stated limits of size - for example, minimum hole diameter, maximum shaft diameter.

Least material condition - The condition in which a feature of size contains the least amount of material within the stated limits of size - for example, the maximum hole diameter, minimum shaft diameter.

Regardless of feature size - The geometric tolerance value is the same no matter what the size of the feature.

Identify and describe the make-up of a feature control frame. R1(340-341), R2(252).

Sentence structure for given feature control frames.

Frame for the geometric characteristic symbol.

Frame for the zone descriptor, feature tolerance and material condition modifier.

Frames for the primary, secondary and tertiary datum references.

Between points identifying under feature control frame.

Reading feature control frames.

Figure 18. Reading a Feature Control Frame.

The feature must be parallel within a five-hundredths of a millimeter tolerance zone relative to datum feature A.

The feature must be positioned within a one-thousandth of an inch cylindrical tolerance zone at maximum material condition relative to primary datum feature A, secondary datum feature B, and tertiary datum feature C.

Identify the symbols representing the following (see Table 1 for correct geometric characteristic symbols): R1(340), R2(252).

Straightness.

Flatness.

Circularity (Roundness).

Cylindricity.

Profile of a Line.

Profile of a Surface.

Angularity.

Perpendicularity.

Parallelism.

Position.

Concentricity.

Symmetry.

Circular Runout.

Total Runout.

Maximum Material Condition.

Least Material Condition.

Diameter.

Between.

Basic Dimension.

Table 1. Geometric Characteristic Symbols.

Figure 19. Common Symbols used with Geometric Dimensioning.

UNIT F: Geometric Dimensioning and Tolerancing

Competency: D506.00

Demonstrate basic geometric dimensioning and tolerancing techniques

Objective: D506.02

Construct a drawing with geometric dimensions and tolerances

Requirements: Each student is required to apply geometric dimensions to a simple drawing. Your instructor will either provide you with the drawing below or ask you to reproduce it using the appropriate CAD software.

1.	The drawing should be completed at a scale of 1 : 1.

2.	Use accepted drafting standards for all line weights.

3.	Add your name, problem number (D006.02.001), scale, and date in the title block.

4.	Time Limit = 90 minutes.

5.	Your work should reflect an understanding of the basic concepts related to geometric dimensioning and tolerancing. It will be evaluated on your ability to correctly draw and apply geometric dimensions, feature control frames, datum feature symbols, and basic dimensions.

6.	Apply the following information to the ANGLE PLATE:

a.	Make the right-hand face in the side view flat within .005. Identify this surface as datum feature A.

b.	Make the bottom surface in the front view perpendicular within .005 to datum A. Identify this bottom surface as datum feature B.

c.	Make the left-hand surface in the front view perpendicular within .005 to datum A (primary) and B (secondary). Identify this left-hand surface as datum C.

d.	Make all dimensions basic except the size tolerances (the limit dimensions).

e.	Position the two larger holes within a diameter tolerance zone of .010 at MMC relative to datum A (primary), B (secondary), and C (tertiary).

f.	Position the .250 diameter hole within a diameter tolerance zone of .008 at MMC relative to datum A (primary), B (secondary), and C (tertiary).

g.	In the front view, identify the top left-hand corner as point X. Identify the bottom right-hand corner as point Y. On the surfaces between points X and Y (toward the top right of the view), apply a profile of a surface tolerance of .020 total referenced to datum A (primary), B (secondary), and C (tertiary). Under the profile feature control frame state that the tolerance applies between points X and Y.

Assessment: The problem will be evaluated based on the following criteria:

Criteria	Point Range

Correct format and placement of feature control frames	50 points

Correct format and placement of datum feature symbols	30 points

Correct identification of basic dimensions	10 points

Correct application for identifying points X and Y	5 points

Titleblock information	5 points

Rubric for Geometric Dimensioning and Tolerancing – Construct a drawing with geometric dimensions and tolerances – D506.02

Correct format and placement of feature control frames

Feature control frames do not have the correct format. Feature control frames are not placed in the correct location.	Most feature control frames have the correct format. Most feature control frames are placed in the correct location.	All feature control frames have the correct format. All feature control frames are placed in the correct location.	Total Points
0-35 points	36-45 points	46-50 points

Correct format and placement of datum feature symbols

Datum feature symbols do not have the correct format. Datum feature symbols are not placed in the correct location.	Most datum feature symbols have the correct format. Most datum feature symbols are placed in the correct location.	All datum feature symbols have the correct format. All datum feature symbols are placed in the correct location.	Total Points
0-21 points	22-27 points	28-30 points

Correct identification of basic dimensions

Basic dimensions are not correctly identified.	Most basic dimensions are identified correctly by placing a box around them.	All basic dimensions are identified correctly by placing a box around them.	Total Points
0-6 points	7-8 points	9-10 points

Correct application for identifying points X and Y

Neither point is identified correctly.	Only one point is identified correctly.	Points X & Y are identified correctly.	Total Points
0 points	3 points	5 points

Titleblock information

Major errors in titleblock information.	Minor error in titleblock information.	All titleblock information is shown and spelled correctly.	Total Points
0 points	3 points	5 points

Total Score

Portfolio Development and Representation

007.

Demonstrate portfolio development techniques

007.01

Describe methods for creating an electronic portfolio

007.02

Create an electronic portfolio of your engineering graphics work

UNIT G: Portfolio Development and Representation through the use of Desktop Publishing.

Competency: D507.00

Demonstrate portfolio development techniques.

Objective: D507.01

Describe methods for creating an electronic portfolio.

Introduction

The purpose of this unit is to help students develop an electronic portfolio of their work from the course. The intent is for the portfolio to be used to showcase their best work to potential employers or as an application for college or university entrance. This unit covers some of the basic content students need to know when creating electronic portfolios. The tools and software used to deliver this unit will vary between school systems; however, every student should have access to some means of creating a basic electronic portfolio.

Also included in this unit will be basic desktop publishing. With the demand on drafters to stay on top of the latest publishing techniques, the ability to exchange drawing as well as image files and converting DWG files to image files is almost a necessity. We will include these in this unit.

Benefits of Electronic Portfolio over a Hard Copy Portfolio

A. Storage and Accessibility
With traditional portfolios, folders, boxes, or 3-ring binders hold papers, pictures, cassette tapes, and more. With an electronic portfolio, information can be stored digitally on a computer hard drive or some sort of removable media (floppy disk, Zip disk, CD, etc.). This electronic information takes up very little physical space and is easily accessed. Viewers have instant access to the information without looking through several mediums or loose documents.

B. Multimedia and Presentation
You can easily add sound, pictures, graphics, and even video to an electronic portfolio. Depending on your audience, you can ooh and awe as much or as little as you want.

C. Computer Skills
Students can gain valuable computer skills as well as desktop publishing skills while creating or editing parts of their own electronic portfolio. These skills will also enhance student’s employability skills.

Principles of Desktop Publishing

The role of drafters continues to grow with change in industry. More and more, they are being called upon to create documents requiring some knowledge of desktop publishing, either for a job proposal, a company report, or even a technical manual. If you sending a document electronically, or pulling a drawing into a document another document for others to see, the need for knowledge of producing documents of publishing quality is becoming a must.

Publishing is the process of producing typeset pages, which may include text, illustrations or drawings, and even photographs arranged in an attractive format that is ready for printing. The publishing process involves three major activities:

Preparation

Page makeup or layout

Printing

Desktop Publishing Systems

A desktop publishing system consists of a combination of software and hardware. Both the software and hardware requirements are somewhat different from CAD systems.

Tools Necessary to Create an Electronic Portfolio

Computer

A PC with AV (audiovisual) capabilities works best. You will want video input and output, as well as audio in and out.

Scanner

A flatbed scanner will help to import documents that are not PC generated.

Digital Camera with close-focus adjustment (macro)

This type of camera lets you focus in close enough to capture your work samples if a scanner is not available. It also allows you to capture video and take single frame pictures.

If you don't want to invest in a digital camera, you can take pictures with your 35mm camera and ask your photo processor to put your images onto a CD -- or you can import your printed photos with the above flatbed scanner.

A Multimedia Software Program

Perhaps the easiest software for creating your portfolio is Microsoft’s PowerPoint. Others are Corel, Hyper Studio, or several Adobe programs.

Once the portfolio is completed, it can be saved to several formats or media types, or could be uploaded to the Internet so that it could be shared with educators, prospective employers, or friends.

Producing Your Portfolio

It is important when producing your electronic portfolio that you do so in a user friendly package to allow the viewer ease in viewing. It may be necessary, if possible, to contact your viewing audience and make sure your product can be viewed at their facility. Not only software programs, as in Microsoft’s PowerPoint, In Design from Adobe, Quark Press from Quark, Inc., but make sure the operating system is compatible. Microsoft Windows, Macintosh System X, and UNIX are all examples of operating systems.

Be sure to include in your presentation instructions as how to view your electronic portfolio. No matter how great it may be, if your viewer can’t operate it either by your complexity or their lack of knowledge, you will make an even greater impression if you make your presentation user friendly.

Backup your work. Today’s most common form of archiving is the CD (compact disk.) You may wish to also print a hard copy for record keeping.

Proof your work carefully before sending it to any prospective viewer. Have another “set of eyes” to look it over. Nothing is more embarrassing than to miss and obvious or careless mistake.
Terms and Definitions

Desktop Publishing: in publishing, the process of page makeup when it occurs on a desktop computer system.

Flush left: the alignment of text where all type is in line on the left side of the paragraph. It is also commonly called rag right.

Font: the detailed appearance of the type within a type family.

Indent: in publishing, setting the left or right margin of text in from the base margins.

Justification: alignment of text in a paragraph. It causes text to fill text lines in a paragraph, leaving no spaces at either side of the text line.

Kerning: the horizontal space between letters.

Landscape: the horizontal placement of a document.

Leading: the vertical space between lines, measured from the base of one line to the base of the next.

Pasteboard: the area in a software program where an image can be imported into a document or template.

Portrait: the vertical placement of a document.

Pica: the unit of measure commonly used in publishing. In general, 1 pica equals 1/6 of an inch, or 12 points.

Pixels: a collection of tiny dots, or picture elements, that makes up raster images.

Raster file: a drawing file format that consists of a collection of pixels, or picture elements.

Template: a special blank page that controls the layout of the page.

Tracking: the horizontal space between words.

Type: the letters and other characters as they appear on a printed page.

Vector file: a drawing file format in which the placement of geometry is defined using a set of mathematical instructions.

Word processing: a computer program or software used to layout type and images when creating a document for desktop publishing or portfolio.

Definitions of Common Graphic File Extensions

Drafters should be familiar with conversion techniques and the file formats likely to be required for desktop publishing. File formats vary with specific software. Here are a few of the commonly used extensions:

Encapsulated PostScript (EPS)

Tagged-Image File Format (TIFF or TIF)

Joint Photographic Experts Group (JPEG or JPG)

Bitmaps (BMP)

Graphic Interchange Format (GIF)

Metafile (MTF)

Converting CAD Drawings

Because the number of illustration file formats accepted by most desktop publishing programs is limited, CAD drawings must usually be converted into a different format. By default, AutoCAD creates drawings in DWG format. This file format is commonly used among CAD operators, and more and more other types of CAD software can sometimes read DWG files. Many CAD programs can create Drawing Exchange Format (DXF) files and Initial Graphics Exchange Specification (IGES) files. These file formats work well to share among different CAD systems, but none of them are commonly accepted by desktop publishing programs. Most CAD programs can export to other file formats. Below are a few accepted extensions:

Screen Capturing

When the need to include an illustration is necessary and perhaps the software program being used cannot be easily exported, you may use what is commonly known as screen capturing. Many screen capturing software packages are available. However, one common way is to use the Windows program Paint. Simply open your file program in which the illustration is located, and have the view you wish exported on your screen. Simply hit the “print screen” or “prt sc” function key on your keyboard.

Next, launch, or have open, Paint. Then, simply go to the EDIT menu, and select paste (or hit “ctrl + v”.)Your entire screen will be imported into the program, as shown below.

Next, select the area you wish to be illustrated, using the “select” feature window.

Next, in the EDIT menu, choose COPY. Now, select NEW from the FILE menu. When asked if you want to save changes, select no. Now, once the new window is opened, choose PASTE from the EDIT menu. The area you selected will be inserted into your screen.

Now, simply choose SAVE AS from the FILE menu and choose which extension you wish to export your picture.

Another common and easy way to capture images is again to use the print screen function, and paste the image into PowerPoint. In PowerPoint, you can add multiple images, as well as, include text. When you have the image as you want, one of your save options is to save it as a desktop recognized image, like JPEG, TIFF or GIF. The advantage of using PowerPoint is that the file can actually be saved as a named image. Using the COPY and PASTE features in Paint will not allow easy move ability once pasted into your document.
What to Include In an Electronic Portfolio

Title or Opening Slide. The title slide or opening slide should show the name of the student, the year, and the teacher. This slide might also include a picture or video of the student.

Table of Contents. This slide shows the viewer the contents of the portfolio at a glance. On a web document, buttons can be added to link the viewer to the desired information. The viewer can choose what information he/she wants to see and in what order

C. Information Slides. These slides will hold information, as much or as little, as student desires. If work has been saved for entire career in high school, include samples of best work, even if some may be from Drafting One. Ideas for slides:

Hand lettering sample (can be scanned in)

Samples of detailed sketches (can be scanned in)

Samples of manually drafted drawings (can be scanned in)

Samples of computer-generated work, including assembly drawings, detailed drawings, etc.

Photos samples of any models, which may have been fabricated from drawings.

Also include the following information, (these may be modified for either application for work or college):

Letter of Introduction

Letter of application

Resume

References

Certificates, awards, and honors (can be scanned in)

Explain the following:

A.	Explain what should be included in a portfolio.

1.	Letter of application

2.	Resume

3.	References

4.	Certificates, awards, and honors

5.	Collection of work from the course

B.	Common graphics file formats.

1.	bitmap graphics files.

2.	vector graphics files.

C.	Methods for screen capturing graphics.

D.	Methods for exchanging files between CAD programs.

1.	Creating a bitmapped image from an AutoCAD file.

2.	Moving 3D data between CAD software.

UNIT G: Portfolio Development and Representation

Competency: D507.00

Demonstrate portfolio development techniques.

Objective: D507.02

Create an electronic portfolio of your engineering graphics work.

Requirements: Each student is required to create an electronic portfolio from the course. This portfolio may be in the form of a PowerPoint presentation, a web document, or other instructor approved electronic format.

Assessment: The Portfolio will be evaluated based on the following criteria:

Title or Opening Slide	10 points

Table of Contents	10 points

Information Slides	80 points

A break down of the information contained on these slides could contain the following:

Hand lettering sample (can be scanned in)

Samples of detailed sketches (can be scanned in)

Samples of manually drafted drawings (can be scanned in)

Samples of computer-generated work, including assembly drawings, detailed drawings, etc.

Photos samples of any models, which may have been fabricated from drawings.

Letter of Introduction

Letter of application

Resume

References

Certificates, awards, and honors (can be scanned in)

Rubric for Portfolio Development and Representation – Create an electronic portfolio of your engineering graphics work – D507.02.01

Title or Opening Slide

The title or opening slide does not exist, or shows no effort in construction.	The title or opening slide does exist, but is of poor quality or shows little or effort. Lacks information.	The title or opening slide shows care and effort. Information necessary to explain portfolio is on the opening slide or slides.	Total Points
0-3 points	4-7 points	8-10 points	10

Table of Contents Slide

The table of contents slide does not exist, or if it does, it shows no effort in construction or formation.	The table of contents exists, but is of poor quality and shows little or effort.	The table of contents is complete and lists all information of following slides.	Total Points
0-3 points	4-7 points	8-10 points	10

Information Slides

No, or less than 3, information slides. Slides show no effort or care. Information criteria are incomplete. Little or no organization of slides. Checklist _ Hand lettering sample _ Samples of detailed sketches _ Samples of manually drafted _ Samples of computer-generated work, including assembly drawings, detailed drawings, etc. _ Photos samples of any models, which may have been fabricated from drawings. _ Letter of Introduction _ Letter of application _ Resume _ References _ Certificates, awards, and honors	Only 3-7 slides shown. A lot of information is missing. Needs more care and effort taken to showcase student work. Only a few examples of student work. Checklist _ Hand lettering sample _ Samples of detailed sketches _ Samples of manually drafted _ Samples of computer-generated work, including assembly drawings, detailed drawings, etc. _ Photos samples of any models, which may have been fabricated from drawings. _ Letter of Introduction _ Letter of application _ Resume _ References _ Certificates, awards, and honors	8 or more information slides. All pertinent information shown. Examples of work are well organized. Colorful and eye-catching slides. Checklist _ Hand lettering sample _ Samples of detailed sketches _ Samples of manually drafted _ Samples of computer-generated work, including assembly drawings, detailed drawings, etc. _ Photos samples of any models, which may have been fabricated from drawings. _ Letter of Introduction _ Letter of application _ Resume _ References _ Certificates, awards, and honors	Total Points
0-26 points	27-52 points	53-80 points	80

Total Score