Originally Posted by
Fish4Fun
One of the reasons I wanted a small CNC router was PCB prototyping. I purchased one of Microcarve's A4 machines back in the Spring, but it wasn't until the past few weeks that I actually successfully routed a PCB. This post is simply a "how I did it" post. It is my hope that others might share the details of their experiences, and that this sharing might help make it easier for others to route a PCB.
I have read about the plug-in for Eagle Cad, and I considered this route, but I am not a big fan of Eagle; I prefer Altium's DXP. Once the schematic and PCB designs were finished in DXP, I "printed" the PCB to a PDF file. Using Adobe I then saved the pdf document to a jpg file. Using Vectric's Aspire I imported the jpg file in as a "bitmap", and then used the "trace bitmap tool" to create the primitives. At this stage I separated the "drill holes" to a "new layer", and created the drill tool path.
The creation of the trace vector's tool path turned out to be critical to "success". I was using a 0.1mm, 45 degree 0.125" engraving bit, and in theory the cut depth should be between 0.0007in and 0.0028in (1/2oz to 2oz copper). What I actually found was that single pass profile cutting even as deep as .010in was problematic, instead, setting the cutting depth to ~0.005in with a pass depth of 0.002in created clean crisp trace profiles. By placing the traces within ~0.030in of each other, no "slivers" or "islands" were left between the traces.
I had several failed attempts using "thin" (.010in to .020in) PCB material; I had my best results so far with 1/16th (0.0625) inch PCB material. I have ordered some 0.032in PCB material, but I haven't tried it yet.
So far I have not attempted a double sided PCB, but I plan to. My thought is to attempt double sided boards by making two ~0.032in single sided PCB's and then placing them "back to back" and using the "via holes" to connect the PCBs. Using a variation of this approach, a 0.007in double sided PCB could be placed between the two single sided 0.032in PCBs for "power planes". For now I am going to stick with perfecting a double sided PCB process.
If any are interested I will post pictures of some PCBs I have routed.
Fish