Wednesday, 20 May 2020

Injection Moulding Tooling Progress

A quick post just to share the exciting progress with the injection-moulding tool manufacture for the MEGA65 case.  The major pieces of the tool have now been produced, as you can see below!

First, here we see the inside of the lower case. The tools are all in negative profile. The big round holes are for the pushers for pushing the cases out of the tool. The smaller round holes are all for screw bosses -- so in addition to the bosses for the motherboard, there are plenty of extra ones for expansion boards, optional internal speaker etc. You can also see the MEGA65 team and major donors for the tooling costs here, so that they will appear as part of every case we produce. We are very proud to recognise some of the key contributors to the creation of the MEGA65 in this way, and wish we had limitless space to be able to recognise everyone who has been involved in the project.

Then we have the outside of the underside, where we can see the hole for the trap-door, and the logos for M.E.G.A. and Hintsteiner.  Note that it seems to be missing 2 of the sides. Those are the sides where all the ports go.  Those sides comea in as separate pieces that move in before the plastic is loaded, and then pull out the way before the pushers push the finished part out of the mould. 

Then for the upper half of the case we have the same inner and outer pieces, although this time quite a bit simpler. The funny sword looking shape in the middle is where the plastic comes in to distribute around, and to hold the piece straight as it comes out warm.
And of course the opposite side of that.  Here we also see the really big diameter holes where the rods go through on which the mould will slide together and apart each time a piece is moulded.  The lower half of the case will have something similar, but of course more complicated because of the pushers that come in from the sides.

Then we have the relatively simple trapdoor slot and eject button on a single little family mould. These can go on a single mould because they are similar enough in volumae that they can be balanced within the mould, to obtain good results.

 Here is the other part for this last mould still being prepared:

While I haven't had the chance to discuss it with them directly, my understanding is that the next stage is the assembling of the tools with all the big rods that hold them together etc, and making sure everything fits together properly.   Then it will be time to load it into a moulding machine at the tooling factory and test it out.  

Once they are happy at the tool factory, they will ship it to the factory where it will actually be used in the production injection moulding machines. They will then go through a commissioning process, where they will fiddle with pressures, gate settings etc to make sure the plastic flow fills every little bit reliably (a bit of a black art), and try to minimise the time per part, so that we optimise the price per case (you pay by the second that the machine is busy). All that will take another month or three, depending on how COVID19 affects everything.

We'll let you know more as soon as we know it, but it's already very exciting :)


  1. For once I'm glad something is not moving at light speed, with the crisis the world is just entering. Hopefully this will all fall into place just at the right time, when we're all well into recovery.
    So just out of curiosity, how many of these molds will be made and what's the number of cases that the machine can make per hour/day typically, do you know?
    Keeping my fingers crossed for the project - great work so far and all the best!

    1. The moulds will be capable of producing thousands of cases over their service life. I'd expect that the moulds would produce one case every few minutes, so more than fast enough for the likely demand for an 8-bit computer in 2020. Certainly, the cases won't be the limiting factor.


  2. Btw, what was the final ports/slots design on the case?

  3. Same as on the preseries, plus break-outs for user port, tape port, external C1565 and component video. Those will require a yet-to-be-designed expansion board. There are lots of screw bosses in the case to take such an expansion board.