thick&tiny PCB design?

i want to design a tiny 3mm thick PCB and since it is super expensive (170$ for 10pcs) to order 3mm thick PCBs, i’m wanted to ask advice on what people with experience think of this design and what issues i might run into.

the board is super simple - basically a breakout for a mini Neopixel (SK6812MINI) where the LED is mounted at one end and the grooves are the 4 Pins (+,-,Din, Dout). shrink-tube is used to couple a 2mm diameter sideglow optic fiber in front of the LED. and conductive thread is used to sew the contacts to the plated half-via groves.

here some photos of my handmade prototypes:

https://c1.staticflickr.com/5/4833/3079 … b737_z.jpg

https://c1.staticflickr.com/5/4855/4481 … 43ff_z.jpg

https://c2.staticflickr.com/2/1964/3186 … b0fd_z.jpg

here a rough sketch:

https://c1.staticflickr.com/5/4889/4398 … 7ce5_z.jpg

here the dimensions i have in mind:

https://c1.staticflickr.com/5/4874/4428 … a79b_o.jpg

questions:

  • what could be issues with milling such small boards?

  • if the narrowest part of the 3mm thick board is 1.5mm wide, does this become a weak point or is the FR4 strong enough, especially since it will be a plated via at that point?

  • in order to minimize waste, could it be possible to layout the boards as illustrated above so that two boards share the same plated via?

  • any tips on PCB manufacturing services that do 3mm thick PCBs in small quantities? seeed studio costs 170$ for 10pcs.

thanks!

hannah

https://c1.staticflickr.com/5/4863/4568 … 4ab7_z.jpg

// more photos here: https://www.flickr.com/photos/plusea/al … 1569545895)

// more documentation here:

http://www.kobakant.at/KOBA/category/lulu/

https://github.com/eTextile/Lulu

Why not order standard thickness PCB and put them back to back?

Actually, thinking more about it, I’d use a more “normal” PCB size with a right-angle light pipe to attach the fiber. I assume that standard fiber optic connectors would be too bulky?