exxos's Atari, Amiga & retro forum

I bought a cheap tiny CNC router to make my own little PCBs for video amps and stuff like that. I have a large 2m long homemade CNC for big work like furniture, but wanted something I could have next to my PC desk to make PCBs and not have to wait weeks for board from china. Today I decided to see if I could tune the CAM to reliably cut tracks for the same CPLD as used on the TF534 and turns out it's possible on this cheap machine even with cheap V-engraving bits. I don't have the files to try to make a full card but at least it's possible. It would be very cool to CNC a TF536 PCB at home.

The square in the photo is 20x20 mm with 0,5 mm pitch. Drag tinning the tracks with flux was no problem. I also tried tighter 0,4 mm pitch but that was too small.

This is the machine I bought. Not great, but works better than I expected after careful tramming. IT was much cheaper than buying the rails and motors I needed to design my own from scratch. I had to replace some screws which were too long under the bed. It's pretty quiet:
https://www.ebay.com/itm/CNC1810-Mini-L ... 2032963932

This is the kind of PCBc I bought the machine to make: I also tested milling the backside of an acrylic piece and filling the pockets with paint: It will even mill brass, albeit slowly:

I'm pushing it here, but it's able to make 0,25 mm tracks and even double tracks between 2,54mm pitch holes. I simulated a 030 socket grid on the right and a 0,5mm pitch CPLD on the left (drawn in CAD). Ball point pen tip for scale.

Just to remind You,
All TF boards are four layer 🤔

I was wondering about that as all the vias seem to go from top to bottom but four layers are clearly visible around the edges.

It's cool anyway. I can make my own CPU relocators and all kinds of stuff in hours now instead of waiting for China.

Looks good @Lynxman , which router did you buy?

This cheap thing: https://www.ebay.com/itm/CNC1810-Mini-L ... 2032963932

I wanted 100x150 mm area and this is the cheapest I found.

Here's a through hole circuit board I milled yesterday:

My new TF534 works in the A2000.

Running at 33 MHz. It's a 33 MHz CPU and I think that's more than enough. My giant 32" CRT. I need to fabricate a support for it so that it doesn't flop around when moved. I'm putting an Dcard-extension to the back for easy access to the disk.

After some more tuning the result is near perfect. 0,15 mm deep milling with the cheap V-bits included with the machine. It took an hour to mill this. Milling a whole board will take a few hours at this level, but it's better than waiting two weeks for a prototype board from China that might not be working because of a design mistakes.
My big CNC machine can do this even better and faster, but it's a chore to set up for small things compared to this.

It doesn't boot with the A2090A and accompanying 20 MB ST-506 harddisk installed but I expected that conflict. TF536 doesnt' have that problem, right?

That should hold it in. A bunch of zip tie pieces:
I also made a holder for the SD-card-extension for easy access. 3D-printed: