How to add allignmet holes for double sided pcb?

hello all, i need to know that how i can add the pcb allignment holes in my pcb to make double sided pcb, i m using my cnc to make the pcbs, have made severa single sided pcbs but need to make the double sided pcbs now…

thanx in advance…

Do you actually mean hole or fiducial markers?
The price of double sided boards is so low these days that I do wonder about the sense of CNC PCBs, plated through holes, finer tacks are just some of the things you miss out on

Prototyping speed is what it is about. No board house is going to have a prototype board ready to test circuit functionality an hour from now.

I just put two vias at the midpoint of the board, either top and bottom or left right depending on how the gcode file for the cnc is flipped.

If the circuit works and more are needed, then it is tidied up ready for the board house.

i actually need the 4 holes in rectangular dimension and distance from each other, inbetween these 4 holes the whole pcb vl be designed, although this can be done manually, but i m looking for a option in the pcbnew, i hav successfully made the .30mm width traces pcb with my cnc, and currently working on copper plating process for double sided boards…

For a one off, I would place the module “1pin” on the PCB (in pcbnew, “Place footprint”). Then edit the pad properties to the hole size you want. Copy the module as many times as you need. Place using relative coordinates, press space to set origin for relative coordinates.

For repeat use, I would create a new module with footprint editor. You can then create 4 holes with exact dimensions so you can place it in one go. If you want to keep the pcb consistent with schematic, create a library part which automatically associates to your custom footprint.

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Sorry to go slightly off topic, but I am interested, which router do you use? I have an old lpkf 92 and it can cut ssop 0.65mm pitch and 0.2mm tracks reliably.

thanx a lot @bobc i got ur point,
@slc i m using desktop router 3020, using kicad for designing and plotting gerber files and drill file, then i m using the flat cam for the gcode conversion, awesum and simple, chk the picture i ve uploaded


Thanks. I have a desktop unit used for drilling photo etched boards as well as the lpkf for routing and drilling. Here is what the lpkf can do with a double sided board.

All the chips are soic and ssop with the traces made as wide as possible.
Shame about the middle aged eyesight soldering skills :slight_smile:

These boards have now been made by PCBWay, $40 for 50 boards manufacturing cost, $60 postage & import duty

seems very nice bro, what softs u used???

The lpkf uses it’s own proprietary software. Unfortunately Windows only but I think the machine works with HPGL plotter codes.

For the other machine I use Geda gschem and pcb which can export gcode, and Linuxcnc for the cutting

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