[sdiy] Molding your own keycaps for tactile switches?

[harrybissell]

For short runs, they use aluminum molds. iirc there is a company
called Protomold that does this sort of thing. They are a fraction
of the cost of a steel mold... in other words they still cost thousands
of dollars :^P

The question would be... how many keycaps could you sell.  Count the
number of synths that still exist that use that same exact keycap... then
guess how many people would pay $1 for the keycap and $5 to cover the
mold cost.

I designed a molded box... once.  It cost $12K for the mold.  We eventually
scrapped the design when the new company tried to buy those boxes at
less than 500 pcs. per run.   :^P

H^) harry

jgrisso at det3.net wrote:

> I have some good news and bad news. First, some background:
>
> The best way to mold switch caps is to do injection molding. This is a
> process where hot molten plastic is rammed into a mold under high pressure
> to form your switch cap. Designing basic switch caps only requires a
> modicum of mechanical design skills and a good CAD tool.
>
> Now, the good news:
>
> Injection molded parts are dirt cheap. We're talking pennies in the right
> quantities.
>
> And the bad news cometh:
>
> The major cost of injection molding is the mold itself. Sometimes referred
> to a tool, or a die. It needs to be made out of high quality steel in
> order to withstand the pressure that the injection ram generates when the
> plastic is rammed into the mold. The cost of manufacturing the mold is the
> major expense in injection molding, ranging from a few thousand dollars up
> to over six figures for large, complex molds.
>
> Assuming you can afford to get the mold made, you'd have to buy a minimum
> of several hundred pieces for most manufacturers to take your order.
>
> Now, this is just my experience - I work with a lot of large companies, so
> I don't know of anyone out of their home doing anything like sand casting,
> vacuumforming, or other types of plastic molding. Usually a good rule of
> thumb is the NRE (non-recurring expense) is inversely proportional to the
> piece price. Meaning, the lower the cost of the custom part, the higher
> the cost of the tooling or what has to be done to set up manufacturing of
> the part.
>
> Best Regards,
>
> Joe Grisso
> Detachment 3 Media
>
> > Has anyone tried this? I recently stocked up on a variety of tactiles on
> > ebay, assuming that the caps wouldn't be too hard to find... Much to my
> > surprise these seem quite rare, and certainly lacking in variety. Mostly
> > black circles and squares, ho-hum. I remember reading about how some
> > people
> > were molding plastics to make their own knobs and such (on another forum,
> > I
> > believe) and the designs I want and pretty simple in terms of shaps, no
> > embedded LED's for the most part. Has anyone worked with this kinda thing?
> > What I'd really like is a soft-touch rubber material in several colors...
> > But I'm clueless where to start. Elastomers?
> >