This is a great video. Here is my best guess for the process, but I'm not a 100%

• Use weird mouse to make design
• Use a water soluble adhesive so the filament sticks
• Clean up edges with a torch
• Put resin in for stability and UV cure
• Put color resin in for front look and UV cure
• Put really cool LED tape on that I would love to have the source for
• Hang

All that white filament. They must go through a lot of nozzles.

Though it's hard to see from the video whether they're using something special like a ruby-tipped one or whatever. Also, maybe a wider nozzle makes a difference.

Awesome video, very cool to watch FDM 3D printing used in a modern manufacturing process. That said I don't think "Mass producing" is the correct term here. A boutique sign company offering custom, chiefly handmade signs (after the printing is complete) is the opposite of mass production: A lot of work is going in to each of these and they probably aren't churning them out.

Here is an alternative Piped link(s):

https://piped.video/gGCD03feE9E

Piped is a privacy-respecting open-source alternative frontend to YouTube.

I'm open-source; check me out at GitHub.

From the same channel, making prosthetic hands with resin 3d printing, lots of expensive equipment and many refining hours from artists https://www.youtube.com/watch?v=eds5UbkluFs