QUOTE(kaysa @ Jul 31 2012, 12:35 PM)
Apa tu CNC Milled? your 3D printer can do or not?
how much is the price? to make each key?
and the mold injection....
RM1xx is how much?
if each key can sell RM10....
you need only to sell 1X to earn back the cost of the Alu sheet right?
is there other costs?
one same mold you can make many different color also right?
er...
My 3D printer can print, but not sure if it able to do such high detail level or not.
it's time to do some "lesson"

Option 1-
Mold InjectedThe price for metal sheets is not fix one. Its estimate around RM100 +/-
Most keycap (99.9%) in the market is hot plastic mold injected. Hot plastic is injected into a mold form by two or more pieces of Alu/Steel base, which already been engraved. (For this case i see it needs only two, top and bottom)
So the hot plastic inside the mold will be cooled and the mold will be crank up, then there you'll get your product. (the keycap)
For mold injection, of course the higher number it able to produce from the mold, the cost will be even up easier. The most expensive part is the mold itself. The more precision a mold is being crafted, the higher the price is. For the plastic? Bla, it's dirt cheap. I can get a 5kg PBT resin with hundred ringgit plus only. The number? you can count

Yes, basicly you can put any color of material into a same mold, also maybe other material like PBT or POM. But not really advisable as the shrinkage of ABS, PBT & POM totally diff
option 2- CNC milledFor example like the one you given, i can take a red color keycap and add a layer of hot red abs plastic on top of it, to thicken the base which will be milled off later. Then wait for it to cool off.
When it's cool up, cnc machine will engrave the shape and then you'll get your keycap.
Basicly, Cnc milled normally is meant to do small quantity job only.