Purpose

This cookbook aims to provide a reference on proper mechanical design etiquette. It is not a guide on how to design (covering all of proper mechanical design is… the point of a mechanical engineering degree) but it addresses topics that should be considered in any design and how to approach them. Examples of what to do (and not to do) are provided.

When in doubt, reach out to your fellow members or leads (Mechanical Lead or Payload Mechanical Lead). It is much more respectable to ask questions, read through resources, and take extra time to justify design choices than it is to make arbitrary design decisions. Mechanical design is often very collaborative!

0.0 File Storage

0.1 Fusion Team

• The team uses Fusion Team as a CAD file storage system. One must be an admin to add members via email.
• Often, work is done on the UTAT Remote Machine . However, they should not be used as a permanent file storage location; once CAD work is done, files are to be moved to the Fusion Team.

0.2 Changes, Versions, Archiving

• Never override someone’s work.
• If you are replacing a set of files, such as when updating an assembly, move the prior files to the Archive folder.
• Fusion Team has a handy system for handling versions of one part. Useful if you’re iterating on a small design, but not good to use for the entire FINCH EYE assembly.

1.0 CAD Etiquette

Good CAD is like good code - you know what everything does, things depend on variables rather than hard-coded numbers, things are clear and labeled. This document uses SOLIDWORKS as the CAD environment.

1.1 Defining Sketches

• Fully defined sketches mean sketches where, as the name suggests, all necessary information is defined. This does not mean that every line and angle are given a value; this would result in an over-constrained sketch. A fully defined sketch provides all and only the necessary information to describe the geometry.
• A fully defined sketch will show in black. Under defined will show in blue.

Figure 1. An under-defined square.

Figure 2. A fully defined square.

Figure 3. What happens when you try to over-define a square.

• The bottom right of your screen also contains information about your sketch, including its status as fully defined or under defined.
• Utilize relations to define your sketches rather than giving arbitrary dimensions. See section 2.1 for details.