Moulds and tooling (continued)

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Daniel Beardsmore

08 Nov 2017, 19:28

hoaryhag wrote: As far as the mold numbering, I did address this in another thread where you posed that question. From what I remember you were mainly wanting to know why you find simple numbering along with more complex numbering in the same board.
I can't remember, or where the post went to, but I've always been more interested in how often companies would be required to recreate the moulds (due to wear), and how ready, willing and able they would be to just retool for various purposes (rebranding for example) unrelated to mould condition. For example, Tai-Hao Aruz seems to had a short lifetime of only a couple of years or so, but in that time it had both Himake and Aruz branding. They must have had a good justification for retooling, unless retooling cost a lot less ca. 1991 than it does today.

(The mis-named) [wiki]MX mount SMK clone series[/wiki] appears to be fairly modern production runs using 90s tooling — the proof of this is the weird backwards and offset mould numbering identical to the 90s switches. I don't know if the bubbly surface finish represents poor plastic material, poor machinery usage or condition, or worn-out moulds.

Moving tooling between countries (viability, and who has done it and when) is another issue. For example, how Devlin in the UK got hold of ITW tooling, or why Omron removed the word "Japan" from the B3G-S tooling (suggesting the tooling was relocated outside of Japan).

We get very little insight here into the industrial processes involved in making keyboards, switches and keycaps, leaving mysteries such as silkscreen vs pad printing, what modern thick ink printing actually is (and whether there's an industry-standard name for any ink printing that doesn't soak in regardless of how it's applied), and so many other things.

Mould technology is interesting because the mould details are often all we get to see, especially on unbranded switches.

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10 Nov 2017, 18:08

We are talking minimal tooling costs here. Keyswitch molds would be so small they would be like inserts themselves, set into an aluminum block, which is then set into the press platen. They could have had tiny inserts for rotating a typesetting or changing a label, or they may have just changed out keyswitch molds for a different label. Irregardless, it would take only an hour or less to do.

I gave some reasons in another thread a mold might fail. Suffice to say, most molds make it to old age. These small molds could easily be shipped to a new factory if the tooling changed hands. They would probably have to modify the aluminum block that the keyswitch molds fit into, or create new inserts to go around the block so it fits in the new platen. All minimal costs really. I think the lack of desire to make new molds of old designs is the limited demand and profit margin involved. It's also possible they didn't acquire the rights to make new molds, just modify the old tooling itself.

We need photos of the molds or equipment used to get an idea of what scale we are talking. My guess is we are talking little machines, tiny molds, a few parts at a time, very fast cycle times.

Keycap molds are what I wonder at more. Has anyone seen these?

If you have any specific questions I haven't answered just let me know. I'm trying to be to the point and not ramble on and on.

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10 Nov 2017, 19:24

The bubbly plastic on the SMK clones is too much gas in the mix. It isn't a product of worn molds. Most likely it's just the best product they could get on their machine with their materials. Worn molds are gonna show themselves in minor part shape defects or texturing. Warping could be caused by too much heat, not enough cooling, or a plastic with less thermal tolerance in the current process versus the old.

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Daniel Beardsmore

10 Nov 2017, 23:51

Under [wiki]Category:Tai-Hao catalogues and brochures[/wiki] there is a Tai-Hao catalogue with lots of photos of the machinery. It's not documented, but might get some idea from it. I do have a photo of the simplified Alps mould machinery (after Datacomp bought it, I assume), but it's not public — I don't know enough about injection moulding to really understand what I'm looking at.

As for cavity and mould counts: under [wiki]Apple Extended Keyboard II[/wiki] you can see Alps SKCM White Damped with something-AG, the first time I've seen the letter dimension exceed a single character, and I'm pretty sure I've seen the numeric dimension exceed 100. In most cases, it's a code like "10D", giving a few tens of cavities per mould and a handful of moulds.

Mould numbering from what I assume is Himake often took the form #X##, e.g. "1A45". Under [wiki] Type T8[/wiki] you can see 7E77, under [wiki] Type OA4[/wiki] you have 3H28, and under [wiki] Type T5[/wiki], "3E26", but these higher codes are for the lower shells, suggesting that their numbers were global instead of local to each product type. Top shells tend to be 1A##. [wiki] Type T4[/wiki] was found with 3A71 on a top shell (again, A) and 2D29 on a lower shell. This seems to be a structured three-axis arrangement that makes it harder to gauge the quantity and capacity of the moulds.

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