Reply with QuoteOh well... thanks for telling us the obvious...Originally Posted by Soldertraining
PCB milling
I made my first PCB with my upgraded CNC. It is a pulse stretcher circuit to stretch step pulses so that they can be made visible with the LEDs I have in my control box. The circuit is pretty simple, just a few resistors and capacitors and two 74HC04 inverters.
Anybody interested can just make the same circuit. If you are not happy with the pulse lengths you can play with the four resistors (R1, R2, R3, R4) and/or the four capacitors (C1, C2, C3, C4) to change the behaviour of the circuit. I used Eagle to draw the circuit and to create the layout.
Once that was done I used PCB Gcode to generate the g-code. It is a free plugin for Eagle.
The PCB turned out really nice, no additional work needed with cleaning the tracks or anything at all. Traces are beautifully milled follow what's been routed with the auto router of Eagle. Manually routing or double sided PCB would have created a more beautiful art work, but it's good enough. Due to lack of 1.2mm high speed PCB drill, I used a simple twisted drill, which was a mistake. It slide into the collet after a few holes, so I had to drill those missed holes manually on a pillar drill. I didn't use the auto levelling plugin of UCCNC, mainly because I did not like the limitations that the probing area is not definable. Perhaps I missed something, but it seems to be necessary for it to start at XY = 0 which is wrong, since that is the edge of the PCB, and it seems to do the first probing along that line, from X0 to Xmax, which in this case is X-100 since X is moving in negative direction during the work because the tracks are on the bottom side of PCB. Probing along X0 is totally wrong in this case, so I found it useless. Also, since my table is levelled and the PCB is pretty small, I decided to skip auto levelling and try without, and I am glad I did that, it saved me a lot of time. Like I said, perhaps I missed something, but for now it does not matter.
Some details about the machining data:
Spindle speed: 22,000rpm
Cutter: 30 degree 0.2mm V-bit engraving cutter
Drill bits: high speed PCB drills, 0.6mm and 1.2mm
Maximum milling depth: 0.07mm
Isolation distance: 0.2375mm
PCB type: fibre glass 1.6mm, FR4 with 35um copper layer
Feed rates: 450mm/min first pass, 650mm/min second pass
Z plunge rate for drilling: 250mm/min
If anybody is interested in more details please visit my blog.
https://adapting-camera.blogspot.se/...d-diy-cnc.html
I also made a video about it, if you want you can see the "Making of..." and the before/after. I am very happy with the results.
Edit:
I just noticed an error in the video. I mill the first pass at 0.04mm depth and the second pass at 0.07mm and nothing else. In the video I wrote that I mill the first pass at 0.4mm and the second at 0.7 and that is just too much for PCB milling. The copper layer is just 0.035mm, so there is no need to mill deeper but I double that value to be on the safe side, however, making it 20 times deeper than necessary would be crazy.
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Last edited by A_Camera; 12-09-2016 at 09:25 AM.
https://www.youtube.com/c/AdaptingCamera/videos
https://adapting-camera.blogspot.com
Re: PCB milling
Oh well... thanks for telling us the obvious...
https://www.youtube.com/c/AdaptingCamera/videos
https://adapting-camera.blogspot.com
Re: PCB milling
To anyone who is awestruck with that extremely valuable and informative piece of knowledge, check out his other informative posts. You won't be disappointed.
Einstein, eat your heart out.
