First Mechanism Design and Test

February 11, 2024

My view is that you have not designed a thing until it has been tested, and it works.

One of the common features of successful bespoke pinball machines is that everything looks over engineered. I suspect the machines built with anything less break; a lot. And this would be very discouraging.

I need to make a few mechanisms. I started designing them with the hardware used in CNC machines and 3D printers. These were heavy and expensive, but very strong. I have seen lots of 3D printed stationary parts on bespoke machines, and the occasional simple mechanism. I decided to try 3D filament printing my mechanisms. Design requirements:

Requirement	Solution	Notes
Strong filament	PET	It works in drink bottles…
Needs to be strong	(1) Set a minimum thickness of 4mm, and make the insides dense.	A dense infill is stronger than a solid print
	(2) Give everything the “snap” test.	If I can snap it in my fingers then it stands a chance.
	(3) Remove sharp corners.	Sharp angles can introduce distortion.
3Rs	Recycled packaging. Recyclable waste.

Proof of Concept Design

The first this to test if the lifting potential of a mechanism printed with my tools and equipment.

I’ll need a 3D design and some Stepper Motors. Oh and a CNC controller, some stepper control modules, a power supply, a lump of wood and some screws and stuff.

Stepper Motors

I got a Box of Stepper Motors:

CNC controller

The CNC Controller is quite generic.

It has a microcontroller board underneath, a standard Arduino clone.

Stepper Modules

You usually have to buy stepper modules to plug into the CNC board that plugs into the Arduino. They come in two types. A slightly higher current version, marketed as HIGH CURRENT, and Slightly lower current version, marketed as HIGH CURRENT. I purchased the HIGH CURRENT version.