Activity 8.4a Working Drawings (Miniature Train)

Introduction

Take a good look around you and notice all of the consumer products that you interact with on a daily basis. A quick visual analysis will tell you that the number of components in many of these designs is quite large. For example, imagine the number of detail drawings that must be involved with the creation and manufacture of all the components in an automobile. Each of the components in the consumer products that you interact with were designed, and it is reasonable to assume that each has some sort of technical drawing somewhere on record.

One aspect of product documentation is the creation of detail drawings. Parts do not appear out of thin air; they must be manufactured. Manufacturers need drawings to make parts. Therefore, documentation is a necessary component of an engineering design process. When compared to the centuries-old practice of technical board drafting, computer aided design (CAD) programs make the creation of technical drawings considerably easier and more efficient.

In this activity you will apply your knowledge of technical drawing and dimensioning standards by creating detail CAD drawings of your train components. Each part drawing must fit within a standard A-Size drawing sheet. Use the title block that is typical in your classroom.

Equipment

  • Engineering notebook
  • Pencil

Procedure

  1. Place the Train Body component into the assembly. This component will be grounded and therefore locked in space. Place the other components into the assembly. These components are separate for the purpose of assembly animation, which will be done in a subsequent activity. Use the parts list below to check off the components as you add them to the assembly.

Item / Quantity / Name / Description / Material
1 / 1 / Train Body / ABS Plastic
2 / 1 / Stack / ABS Plastic
3 / 1 / Hitch Magnet / ABS Plastic
4 / 1 / Hitch Peg / ABS Plastic
5 / 4 / Wheel / ABS Plastic
6 / 4 / Axle Peg / ABS Plastic
7 / 2 / Linkage Arm / ABS Plastic
8 / 4 / Linkage Peg / ABS Plastic
9 / 1 / Cow Catcher / ABS Plastic
  1. Use assembly constraints to model the Miniature Train components. Perform interference analyses on the components to determine if unnecessary overlaps occur. Save the assembly file when complete.
  2. Create a part drawing for each part of the train. Components that require section or auxiliary views must have the views within their CAD drawings.
  3. Create an exploded view of your assembly with balloons and a parts list on a drawing sheet. Unmodified off-the-shelf components do not require dimensioned drawings. Only modified off-the-shelf components require technical drawings. Such drawings will include only the dimensions required to perform the modification.
  4. Assist classmates by exchanging your CAD drawing printouts and checking the drawings for errors. Place a revision block on each drawing to track changes made before drawings are submitted for final evaluation.

Conclusion

  1. Under what circumstances would it be advantageous to pattern a component?
  1. What is an offset and how is it used?
  1. What is the difference between a mate and flush constraint?
  1. What constraint would you use to place a pin inside a hole?
  1. What is a subassembly?
  1. What advantages does CAD have over technical sketching?
  1. If dimensional information can be retrieved from CAD part models, then why do engineers create detail drawings of parts?

© 2012 Project Lead The Way, Inc.

Introduction to Engineering DesignActivity 8.4aWorking Drawings (Miniature Train)– Page 1