Instructables Birthday Mechanical Die

This is a mechanical die.

It is a 3-component mechanism that is designed on CAD and 3D printed to randomly land on exactly one of three options every time.

I will take you through the process of how the mechanism works and how to design your own mechanical die customised to your liking.

My mechanical die is made to be used to play games in Instructables 20th birthday!

This project does not take many materials to make as it is fully 3D printed, except for the optional design after.

Materials:

1. Any CAD of your choice (I used Fusion 360)
2. Orca-Flashforge software
3. Adventurer 5M Pro
4. Yellow PLA filament 2.85mm
5. USB drive compatible with Adventurer 5 Pro (Fat32)
6. Rubber bands

Components

1. Button - The button is used to turn and stop the ratchet when pushed down and pulled up.
2. It is connected to a frame that is meant to keep itself moving on a straight, consistent line.
3. The piece of the button that pushes and stops the ratchet is a protruding triangle that fits into the spaces in between the ratchets teeth. This piece is preferably able to bend slightly.
4. The button should be easily connected to the actual box frame with elastic so it pushes itself back up.
5. Compound Gear - This is the gear that the button turns
6. 6 teeth ratchet
7. 20 teeth spur gear (teeth have to be more than other gear)
8. Gear - this is the final gear that turns
9. 10 teeth gear (teeth have to be less than other gear)
10. Connected to a round face with the 3 numbers for the die

These components can have any design, but need to carry out their intended function.

I made the gear ratio 0.5 (which made the mechanical advantage and velocity ratio 0.5) to affect the way I intended the device to work and feel.

1. The speed of the last gear that is connected to the wheel of numbers must be very high. This is to ensure that the the die is as random as possible. With a gear ratio of 0.5, the output speed would be double the input speed.
2. The button should be short to press and the user should feel some pressure when pressing it. This is just for a better feel and user experience. With a gear ratio of 0.5, the input torque on the gear would need to be double the output torque, ensuring more effort is needed to push the button.

Gears

1. Open the Spur-Gear add-in
2. Top menu → Utilities (or Tools) → Scripts and Add-Ins → in Add-ins find SpurGear (Python or C++ sample) → Run.
3. Fill gear parameters
4. Choose: number of teeth (N), Module (or Diametral Pitch), face width (thickness), bore diameter, and optional backlash. The dialog will show the computed pitch diameter (you’ll need it for spacing).
5. Generate & inspect
6. Click OK / Generate. The CAD creates a component with the gear geometry. If you need a hole for a shaft, open the gear’s component, sketch a circle at the center, and Cut (Extrude) the bore.

Ratchet, Die face and Button

1. These components are easy to make. They just require a well designed sketch with the correct measurements that are extruded
2. The die face must be merged with the second (smaller) gear, and the ratchet must be merged with the first (bigger) gear
3. The die face must have 3 numbers on it, equally spaced and with at least one number matching up with a tooth of the gear (for reference look at the assembly pictures)

Frame

1. The frame is also very easy to make and customise, as it is made up of a base and lid that are simple shapes.
2. The base has two levels, so the gears can connect. It also must have axels extruded out of it wherever needed (2 for the two gears and two for the button frame). The last part of making the base it the connection to the lid.
3. The lid just requires a connection to the base and a hole to display the number.
4. Somewhere on the frame requires a way to attach a rubber band. I did it by cutting in two holes for the rubber band to wrap around the frame.

*View the photos for a better understanding of what the parts look like. Try to stay organised while making the parts, it will be much easier to edit and changes

I will take you through the step-by-step process of how to prepare the file. This can work for any design, not just the mechanical die.

1. On Fusion 360, clink file and export. This will open a window where you can name the file, the type and location. For file type, use STL. Save it to desktop for convenience.
2. Right click the file and in the 'Open with' section, select 'Orca-Flashforge'.
3. Right click the model on Orca-Flashforge and select 'Split' and then 'Into parts'. This is so that you can move the parts individually. Move the parts so that they are all in the boundaries.
4. In the top right of the window, click 'Slice plate'. Once it is done slicing click on the drop-down menu where it says print plate and select 'Export G-Code file'. Save it to desktop.

This is the file that you will 3D print

These are the final steps to transfer the file to the 3D printer and actually 3D print it, bringing your CAD creation to life.

1. Plug in a USB drive compatible with Adventurer 5 Pro (must be Fat32) into your computer.
2. Drag the g-code file from your desktop to the USB. Make sure the file is fully copied into the USB and remember to eject it before removing.
3. Turn on the Adventurer 5 Pro 3D printer and pug in the USB.
4. Go to the printing menu (2nd option from the top) and select the USB option.
5. Find your file and select it. Click the green button to copy the file over to the 3D printer and start the printing process.

The printer will heat up and then start printing. This will take a few hours, the exact amount of time for your design to print will be displayed on the printer screen. Once it is finished, remove it carefully and clean up parts with any supports.

Once all the parts are ready, assemble the die carefully.

1. Place the button in the frame first, with the two support axels in the proper place.
2. Wrap the rubber band around the button and wherever you meant for it to attach to. For me I just needed to wrap it around the frame.
3. Put each gear in their axels respectively, and finally the lid.

The die is ready. Any other design choices are optional.

I made my design using paper, markers and double sided tape. Marker straight on the surface doesn't stick and the ink spreads out.

HAPPY BIRTHDAY INSTRUCTABLES!