Week 9. Casting and molding. I'm hoping to cast my own design of FabISP programmer in plastic to make it durable and fit nicely into USB slot. First I draw two sided mold to cast a mold of silicon rubber for the plastic product. This mold is carved in wax. For drawing I used Solid Works.

drawing

The toolpath is produced using Roland's own programs due problems in Fab Modules.

toolpath

Two millings are necessary the surface being fairly straight. First roughing and then finishing with the smaller mill bit.

millwax

Wax mold is ready. There are two designs on the same block of wax:

mold

Casting setting: scale, vacuum and mixing accessories.

casting

Liquid rubber is cast into mold. This takes around twelve hours to harden.

casted

Rubber mold for the plastic is ready:

siliconemold

The plastic is mixed and cast. This hardens quickly in around 40 minutes.

plastic

Following the instructions, we didn't use any casting removal. This was clearly a mistake:

stuck

I had to cut the test casting out of the mold with a knife. It ruined the mold:

skinned

The dummy product fits nicely into USB after cleaning the necessary parts of the product.

fit

Even the "window" for the LED is in the right place

led

So I made a new mold. I sprayed it with silicone spray and left to dry over night. The blue tape is to safe the contacts during the casting.

newmold

I glued a little peace of plastic behind the PCB and pinned a needle through the mold to it to lock the connector end of the PCB firmly at place.

pinguide

No bubbles, no problems. Perfect cast comes out of the mold!

plasticcasted

The FabISP programmer cleaned and labeled:

labeled

The status LED is behind the logo. It lights up when programmer is redy to program after sticking it to the USB slot. It blinks during programming and stops when the programming is ready.

ledbehindlogo

The .stl file for the mold: