Mechanism Educational Kit - Spur Gears

On my 1st semester studying Industrial Design, I've had an introduction course dedicated to technology and manufacturing. One of the main classes was about basic common mechanisms, the aim was to teach the students the building blocks the machines around us - how are they made and what are the main ways to create or convert motion. The professor named different basic mechanisms and demonstrated them using animations for websites such as 507 Mechanical Movements which is an amazing knowledge base for this topic. However, some students couldn't properly understand the mechanisms shown only on screen - and that's why I came up with "Mechanisms 101"

Mechanism 101 is a series of simple kits, made from parts and materials commonly available to universities and schools. Each kit demonstrates a basic mechanism and allows the user to feel it in his own hands! The kits' size can be scaled up, but the main idea is to build something which is small, simple and easy to make.

The 1st mechanism I chose to build is a simple gear train made from spur gears.

Machines/Tools:

1. Laser cutting machine capable of cutting "soft" materials (wood, acrylic, cardboard)
2. The parts are small so every laser cutter with a working area greater than 6"x6" will be enough
3. The design can be modified to work with a 3D printer instead of a laser cutter
4. Metric Allen wrenches & combination wrenches
5. The design can be easily modified to work with imperial hardware instead of metric (#4-40 screws and nuts instead of M3)
6. This design only used a 2mm Allen wrench and a 5.5mm combination wrench
7. Wood glue of your choice
8. Some small metal spring clamps

Materials/Parts:

1. (1) 12"x8"x1/16" plywood sheet
2. 1/16" acrylic can also be used
3. The design can be modified to work with thicker materials
4. (8) M3x12mm button head hex driver screws
5. (8) M3 Nylon lock nuts
6. (8) M3 spacers 4mm Long
7. Can be replaced by stacked washers, 3D printed parts, etc.

I designed the kit using Fusion 360

1. Free for hobbyists
2. Easy to use without extensive CAD experience
3. There's a built-in McMaster-Carr interface which makes working with COTS hardware so simple
4. There are tons of plugins and add-ons available - like the one I used for the spur gears

1. I started with a basic sketch to define the kit's size and the overall structure, than started creating a component for each part:
2. Front Panel
3. Back Panel
4. 20t Gear
5. 30t Gear
6. 45t Gear

For the COT items (screws, nuts, spacers) I used the McMaster-Carr interface

I have assembled all components and started working on the text & graphics, this can be done using either Fusio360, Adobe Illustrator, CoralDRAW, etc.

Lastly, export a DXF file for each part, make sure to include the text & graphics

The attached DXF file contains all the parts needed

For the laser cutting a used a 50w co2 laser cutter and RD Works V8 software. I imported the DXF files and arranged the parts so they will nicely fit inside a 12"x8" rectangle. I assigned a color for each path and applied settings for cutting, line engraving and fill engraving according to the parts.

1. Apply a small amount of wood glue on 1 side of half the gears
2. Using 2 screws as guides (to match the teeth on the two gears) attach 2 gears together (1 with glue and one without)
3. Let the glue dry while applying pressure using the spring clamps

1. Mount the Front Panel to the Back Panel, make sure to place the spacers in between them
2. Slide the gears into place and used screws and nuts to keep them in place - Make sure to not fully tighten the nuts otherwise the gears won't spin

Congratulations! The kit is ready!