CAD Training

Team 1188 uses Onshape for all CAD design work. Before you get into the training you will need to setup your Onshape account. Follow the links found on https://www.onshape.com/edu/frc to ensure that you setup a student account.

Reading Drawings

Before we begin modeling there are a couple things you need to know about reading and interpreting drawings and sketches.

Abbreviations & Annotations

TYP. = Typical. In the context of drawings, it means that the feature being referred to repeats. 
THRU = Through. This means that the hole or other feature passes all the way through the part.
⌀ = Diameter

Line types

Different types of lines are used on drawings to convey information to the reader. A couple of the most common are shown below.

Section 1 – Basic Modeling

Although our robots can look very complex, they are mostly built up of simple parts. For this training we will look at parts based on how they are manufactured. In general, we have 4 basic types of parts;

  1. 3D printed parts.
  2. CNC’d parts including sheet goods, such as polycarbonate and aluminum, as well as tube stock. 
  3. Lathed parts which are almost exclusively shafts for us.
  4. COTS parts. COTS stands for consumer-off-the-shelf part. In the context of FRC these are parts which are purchased by the team from a supplier. 

Each part has specific design considerations given how it will eventually be produced. For example, we are limited by the size of shafts we can make due to the size of our lathe. 

With that basic understanding we are going to jump right into CAD designing. For each exercise outlined below make a part in your folder on Onshape. If you do not have a folder, or you are not on the 1188 team, or you have not even signed up for Onshape, speak to a coach before proceeding.

Exercise 01.01 – Bearing bracket

3D Printed Parts

Each year for the past several years our robots have featured an increasing amount of 3D printed parts. Many of the parts are simple spacers that could easily be done on the lathe, but it is faster to print these parts. Some parts are more complex and are simply not possible for our team to make without the use of 3D printers. 

Following the step-by-step directions model the part and place it in your folder in the Onshape training folder. Once complete let a coach know so that it can be reviewed. 

About the Part

This part was from our 2019 robot elevator. It was used to hold the hold a bearing in place and limit the lateral movement of the elevator carriage. In total there were 8 of these parts on the robot.

Exercise 01.02 – Frame tube

CNC Parts – Tubes

The most common part we make are machined aluminum tubes. We use mostly 1”x1” and 2”x2” aluminum tube on 1188. The wall thickness of the tubes can vary, and it is important to get the thickness correct. Most of our tubes are either 1/8” or 1/16” wall thickness. 

Following the step-by-step directions model the part and place it in your folder in the Onshape training folder. Once complete let a coach know so that it can be reviewed.

About the Part

This tube was part of the lower frame on the 2019 robot. The robot had two of these one for the front frame rail and one for the rear frame rail.