Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Great comments everyone!

Good idea using 0-ohm chip resistors as bridges.

I believe this method can produce 10mill trace or spaces reliably. Now it's up to me to prove it :-)

Cutting copper foil w adhesive is also a good idea. I now that al lot of folks at the MIT MEDIA Lab use this method. You're limited In how a trace/space you can make and how well the copper sticks (or doesn't).

Cricut is much cruder in how it moves though smilar. I have SureCutsALot, another hacked software that ProvoCraft went after. It does similar functionality thru the USB port and lets you cut sgv files. It has no drag-blade compensation though not many of the good vestor tools the Silhouette has.

A little more on the operation of the Silhouette:
It can't accept G-Code nor be controlled like a CNC machine can in real-time. Once you have the vector file produced or loaded, it cuts on its own. I import a high resolution .bmp image of the Top and Bottom traces, vias and pads. It has an excellent tracing program that produces near-perfect vector objects. I let the machine move the 30Krpm spinning carbide etching tip on its own rather than try to control it intimately from the USB port as a G-Code CNC controlled mill would do. It keeps the tangential speed constant and also the rapids.

The holes are drilled with a hack. The Z-xis is ust solenoid with a spring return. I needed to fool the machine to keep it's "blade" down long enough to drill through the PCB. I generated a multiturn spiral vector image reduced to .001"x.001" that I place at each desired hole location. The XY stepper motors don't respond to this small movement...but takes time to try so it works fine. I also discovered a way of aligning the top and bottom for 2-sided PCBs.

I'm still close to my altruistic goal - to make this a low effort project for the user......so good....so far :-) Keep the great comments coming.

Mike





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