Making keycaps using injection molding

[ghastone]

Hey All,

So I was thinking about getting into making my own artisan keycaps. My dad actually owns an industrial injection molding machine, was wondering if anyone has any thoughts onto next steps. I mean I'm assuming i can make the designs on my computer and probably order the metal molds from somewhere to make some keycaps. Let me know your thoughts or if I'm in way over my head.

Thanks,
Geekhack: Ghastone / Reddit: u/Jiraffinator

[heedpantsnow]

How much do the metal molds cost?  I would imagine quite a bit...

[ghastone]

Ya that's what I'm not sure of, when my dad was using the machinery, he did all the injection molds himself with a cad/cam machine. I would assume though once you have a design, you could make keycaps quite easily using injection molding. I'm sure it will take some practice getting it right though.

[Leslieann]

I believe either Solidworks or Autocad has a mold making tool. Render the part and it will tell you how to make the mold.

I've read that SP charges $45 for custom keys, which means about that for the mold (they are small luckily). However, they already have most of the CAD info in hand as well as an experienced mold maker making them (injection mold makers are highly specialized), they may even own the cnc mill. And that's for one key. Get it wrong (did you account for shrinkage?) or need multiple keys and the price goes up that much, every time.

Now the worst part...
You could get them 3d printed, however, my experience is that it's MUCH more expensive to 3d print metal than it is to have it machined. Unfortunately, finding a shop willing to take a bunch of small one off work like that will not be fast or cheap. They dislike jobs like that as they tie up the machines and manpower for little profit. So they may do it (expect a few to blow you off) but expect them to fit you in when and where they can. Could be weeks or months depending on their workload.

Bottom line, unless you know someone, don't expect a full set of molds for anything under $10k, probably closer to 20 or 30k. You could cut that by 60% if you have them done in China, however a bit of warning, while they may do it cheaper, and maybe even faster, you may not get anything like what you expect and you have no recourse on getting your money back. If you have never done business with Chinese manufacturers, don't set your expectations high. They are capable of good and cheap, but quite often the language is an issue, and even if you get beyond that, there are a lot of unscrupulous manufacturers who will do everything they can to make it as cheap as possible. That includes wrong materials, improper surface finish, poor packing, wrong shipper... They don't care, they got paid, you have little to no recourse, and there is 50 more people waiting in line behind you. I've known more than one company who had to send someone over to watch over the manufacturing process before it was finally done right.

Once you have the molds though, yes, you can crank out keycaps for pennies.

[ghastone]

Thanks for the reply. This is where I wish we still had the cad/cam machinery

[user 18]

I've read that SP charges $45 for custom keys, which means about that for the mold (they are small luckily). However, they already have most of the CAD info in hand as well as an experienced mold maker making them (injection mold makers are highly specialized), they may even own the cnc mill. And that's for one key. Get it wrong (did you account for shrinkage?) or need multiple keys and the price goes up that much, every time.

That's the insert for the legend, not for the key itself. Molds for a whole key are more expensive -- I believe the quote for R4 SA profile shifts (2.25 and 2.75u) was in the neighbourhood of $4000+ per key.

But you're right, the molds are the expensive part, and the materials are very cheap in comparison.

[KatzenKinder]

If you had a killer (and I mean really really killer ball wrenching amazing) design, you might be able to justify the cost of one mold, assuming there's enough interest?

That's a pretty massive risk though...

[ghastone]

Ya, I don't think I ever plan to make a substantial amount of money doing it, figured it would be a nice hobby, or, if someone already did have a design, maybe I could help out.

[CPTBadAss]

You may want to talk to obra who has a lot of experience with sourcing injection molds.

And from the last time I looked into this, SP has a mold setup so that only part of the mold changes and that's why the fee is $45. If they had to retool the entire mold from keycaps to say Legos, they probably would have to spend much more.

[nubbinator]

I'm surprised no one has mentioned this yet.  You can buy mold frames and do epoxy molds.  They don't last as long as milled molds and you have to be very careful to make sure that the part will be able to be separated from the mold, but they are dramatically cheaper.  It's something I was looking at, but the injection molding machine has been too far outside what I can afford.

[ghastone]

I wonder if that could hold up to the heat, or if it will just melt.

[nubbinator]

People wouldn't do it and places wouldn't sell frames and epoxy resins for it if it didn't work.

[heedpantsnow]

Doesn't Martin do injection molding for his caps?  Seems like it but wth do I know.

[Leslieann]

Resins work, for lower pressures and low volumes.
The higher the pressure, the faster the wear. Higher pressure, higher strength object.

Yes, you could do keycaps with these systems, but from what I've been told, it's only about 100 uses before they start to break down even under good conditions. Considering the time and effort it takes to make these molds you will spend as much time building and prepping molds as you will actually making keys with them.

The specialty key makers are making an object (pattern) and making a mold from that in silicone then casting with resin. They can reuse the pattern over and over when the mold falls apart. It's okay if things are not 100% perfect, they are limited editions, hand done. When you are talking double shot injection molded keys using multi-part molds with precision lettering and straight lines, you are talking a whole different ballgame.  No one wants a T that looks like it was hit by a truck.