dinx71,
It is a lot of holes, but I can drill about 300 precision placed holes in less than 5 minutes on the cnc mill at work so no problem, I don't even have to put in the hole coordinates since express pcb can produce dxf files, I put it on a disc, put disc in mill, set up part and tool zero and drill, drill ,drill.
As far as carbide, that's all we use so the shop is full of it. Hole sizes I use are .032, .046, .062, and .125. If I need any bigger holes I just interpolate them with the .125, any hole size up to 20 inches diameter, shapes, slots, etc....all easily done. I have drilled hundreds of holes with the same tooling so it holds up very well (I don't use drill bits, only 4 flute end mills).
"What's the current limit on your traces? Does the cad software make the traces wider if necessary?"
The software does not decide for you. You click on the size you want and go from there.
I usually make them as wide as possible with the space I have without going overboard with it. The traces on the above circuit boards are (upper board .040) and (lower board .060).
Max trace width is .250 with their software, you could actually go wider if you place traces next to each other with no spaces between (not sure why you would want to though) the program also has filled planes that you could use for traces and they can be any shape you like.
This taken from the help section on express pcb.
" A good trace width for low current digital and analog signals is 0.010". Traces that carry significant current should be wider than signal traces. The table below gives rough guidelines of how wide to make a trace for a given amount of current.
- 010" 0.3 Amps
- 015" 0.4 Amps
- 020" 0.7 Amps
- 025" 1.0 Amps
- 050" 2.0 Amps
- 100" 4.0 Amps
- 150" 6.0 Amps "
Matt
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