lasering PCB's to create circuitry...

[Pete Andrew]

I've recently been asked if it is possible for my 30watt CO2 laser to laser away the copper on a PCB - in effect for me to create the circuit board for a friend.... a prototype and maybe a small run. He would draw out what he needs and I would laser away the unwanted copper leaving the circuits. You can probably tell that I know next to nothing about this kind of thing, though i am pretty damn sure that when the average circuit board is manufactured there will be more exacting standards of dust-free-ness than I could hope to achieve.....
That said, I am not phased by this idea in principal. After all, how hard can it be....? Is there anything potentially harmful in a typical piece of coppery and resiny PCB that i should be wary of? The copper will be thin.... a bit like etching the back off a mirror surely? Has anyone tried this.... and with what results?

[Ferry Griek]

Just forget about it!!!! 30 watt CO2 laser will not i repeat not even scratch the copper! If you want to do something with your laser and pcb's you could try something like coating the copper with a thin layer of etch resistant paint, and blast away the paint at the area's you want to etch the pcb.

In my opinion it's far more easy to use the fototransfer method to create a simpel pcb

just my 2 cents

Best regards....

[Chester Lindgren]

You can at least cut him a stencil for when it comes time to solder everything onto the circuit board....

hackadaydotcom/2010/03/19/laser-cutting-solder-stencils/ or synthetosdotcom/blog/how-to-make-an-eagle-solder-mask-stencil-for-an-laser-cutter/

[Dan Hintz]

you could try something like coating the copper with a thin layer of etch resistant paint, and blast away the paint at the area's you want to etch the pcb.

This is the only option open to you, Pete... if you had a fiber/YAG laser, then we could talk, but the wavelength of a CO2 laser will not touch a metal surface at those powers.

[Richard Rumancik]

Pete, as others have said, you cannot directly etch the copper. Many years ago I considered the etching option but realistically with the fast-turn around you can get these days at pretty low cost, it would be hard to justify trying to laser-etch a resist (then chemical etch) to make a board. Aligning two sides will be required; all the holes will have to be drilled separately (the laser can't do it); then you have no PTH (plated through holes) and of course are limited to simple two-layer boards. When someone can get protos in 3 days for less than $100 you can't compete with that using a laser. It just isn't the right way to make a board.

However, there may be other products where laser-etching a resist could make sense.

[matthew knott]

As it happens i made some the other day to demonstrate it could be done, only single sided and all surface mount but from the gerbers to having a working board was about 6 minutes. TBH with a laser printer and light box and some ferric chloride i could have done the same thing in about 20 minutes, cost for laser £18k, cost for diy pcb kit £150 so i doesnt stack up, FYI this is with a 40 watt fiber laser!

[Ivan Pavletic]

I have made several PCB with laser. Engraving copper is not possible. This is how I'm doing this:
Take some tape ( I took avery film tape, not sure if this is right name), stick it on a copper side.
Laser cuts around the lines.
Then, I remove tape, leaving tape where the copper needs to stay.
Next comes etching with acid
Result is perfect!

[Rich Harman]

I have made PCBs by spray painting the copper, lasering away the areas to be etched, then put it in a ziplock bag with a bit of ferric chloride for a few minutes. A few swipes with a paper towel and solvent to remove the paint and it is done.

edit: I forgot a step. Generally before etching I will drill all the holes using a CNC mill. If you drill the holes after etching it is much more likely that the copper will be pulled up around the holes.

[Ivan Pavletic]

edit: I forgot a step. Generally before etching I will drill all the holes using a CNC mill. If you drill the holes after etching it is much more likely that the copper will be pulled up around the holes.

Every day i learn something new and useful
Thanks for sharing that Rich, I'll try that with my next project!