[Coco] 3d printed EPROM cartridge housings

Mark J. Blair nf6x at nf6x.net
Mon Nov 2 21:16:40 EST 2015

> On Oct 26, 2015, at 10:55 , chadbh74 <chadbh74 at hotmail.com> wrote:
>   I'm in the works of building a delta 3d printer that I plan on using to
>   Make, among other things, cases for EPROM boards.   I've been working
>   on the layout for each half of the cartridge in Google Sketch up 3d
>   modeler,  which I can export to the needed .STL format and convert to
>   .gcode from there.  I was wondering though if perhaps someone already
>   had a perfected layout in STL they might share for reference.  I intend
>   to make a version with a slot for my external controllers.  The jhead I
>   ordered is all metal and is supposed to be able to do many types of
>   materials, although I've only ordered PLA and ABS for the time being to
>   experiment with which would be best for different cases.  If anyone
>   could offer any insight Into this I would greatly appreciate it.
>   Thanks!

Coincidentally, over the weekend I decided to release the solid model that I created a couple months ago for CoCo Program Pak housings:


The model is as close as I could get it to the original housings, including draft angles needed for injection molding. The only major detail that I couldn't get right was the edge blending of the finger slots.

I've tried having it printed in the SLS process at Shapeways, with good but not perfect results. I plan to make a YouTube video about that fairly soon, and I also plan to revise the design for better results at Shapeways. I'll make it available there for purchase after I revise the design, but I won't be surprised if nobody chooses to buy it there. Given the cost of printing in their SLS process, I'll be asking for $68.09 for it, with a very small profit margin. But if I ever become a billionaire, then I'll have tooling made to mold new cases for cheap. :)

Another collector who has an FDM 3D printer tried printing my model, and shared pictures in a conversation on Twitter. He mounted one of my CoCoEPROMpak cards inside. Here are some highlights:


and here's my CoCoEPROMpak card:


A modified design made to work better on common FDM printers would probably yield much better results.

Mark J. Blair, NF6X <nf6x at nf6x.net>

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