Summary

A version covered with 3mm acrylic plate, which should be laser cut using an SVG file. Model with built-in compression spring. See below for spring specifications.

https://www.monotaro.com/p/0730/2836/

Here are the balls for the Pachinko Roll Machine series Please print out the details.
https://www.thingiverse.com/thing:4626734

https://denshiman.com/pachinko.html