Introduction: Printed Circuit Boards (PCB) Using the Laser Cutter
This is a new twist on an existing process, which allows you to make super accurate PCBs. It basically involves spray painting copper board, laser cutting off the paint and then putting the board in a bath of Ferric Chloride to remove the unwanted copper. This method is particularly good when using large chips as they need very accurate pin spacing.
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Step 1: Spray Copper Board
Cut your copper board to the required size and spray paint it with a nice even coating
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Step 2: Laser Cut the Board
Draw up your circuit diagram, I just use illustrator for this, and remember to mirror it if required. You also need to remember to reverse the colours of your diagram for eg the parts of the board that you want to remain copper should be white and everything to be removed should be black. put the board in the laser cutter and cut away the paint where desired, make sure it has cut clean through to the copper surface.
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Step 3: Bathe in Ferric Chloride
Place your board in a bath of Ferric Chloride. Use a plastic tub for this and wear gloves etc, rhis is pretty horrible stuff. It helps to warm the Ferric Chloride a little, I do this by placing it in the sun. Leave the boards for about half an hour, it helps to scrub with a sponge. Sponge and bathe until all the copper is removed.
Step 4: Clean Board
To remove the remaining paint give the board a scrub with nail varnish remover or resist remover.
Step 5: Drill Board
If you require to drill the board do this with care and a small drill (probably no bigger than 1mm). It helps to do this on a pillar drill, but can be done with a hand drill if more accuracey is taken.
There you have it, an accurate and reliable PCB!!
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17 Comments
13 years ago on Introduction
Is that PCB photoresist paint you're using?
Reply 13 years ago on Introduction
No I'm just using standard spray paint, I've never heard of photoresist paint, where can you buy it, is it any good?
Reply 12 years ago on Introduction
I've tried a lot of spray paints for this with our 60-watt Epilog laser cutters at TechShop to create resist layers on copper clad board, but the laser etching seems to leave a very thin invisible water-resistant coating on the copper, even though it looks like the spray paint has been removed.
The ferric chloride will not reach the copper because of this invisible layer.
Did you encounter this in your experiments, and if so, what did you do to get past it?
Reply 5 years ago
Jim, did you ever find a solution to this? I'm stuck at the same point.
Reply 11 years ago on Introduction
Jim,
Do you use the "air assist" on your Epilog? I haven't tried this yet, but I'm wondering if the film you're seeing could be paint vapors that are re-settling on the piece after the laser moves away. If so, and if mashorter is using the "air assist" and you aren't, then the "air assist" may be blowing his vapors away before they have a chance to settle. Just a shot in the dark but I figured I'd throw it out there.
6 years ago
what is the power of this laser?
10 years ago on Introduction
Cool idea.
The problem is that it's a bit slow. There’s a lot of laser time since you have to cut away everywhere there isn’t going to be traces. Inspired by this idea, I played around with the following:
-stick wet paper to the copper clad
-cut out the traces you do want
-spraypaint through it.
-let dry
-remove the paper
-etch
I didn’t quite get the result I was looking for, but I think I could with a bit more monkeying around with laser settings and the masking material.
Reply 7 years ago
I dont do electronics so i may be wrong about this, but wouldn't a simple offset around what is required be sufficient instead of removing all the unwanted copper?
8 years ago on Introduction
A makerspace, complete with laser cutter, opened in my community which is why I searched here. The first question I have is, could you simply cut all the way through the copper with the laser cutter, skipping the painting and etching stages? Could I use the laser cutter to make the drill holes at the same time?
Reply 8 years ago
you would need a high power laser, and even then it might over etch.
10 years ago on Introduction
Would something like this work with a dvd burner laser (or similar aprx 1W laser) if using a very thin coat of paint? I really can't afford an expensive CO2 laser
13 years ago on Introduction
how precise are you able to do a pcb with this? Is trace width of 15mil possible or maybe even less? How much clearance do you have between traces?
13 years ago on Introduction
where can someone get a low cost lazor cutter or access to one to do this?
Reply 13 years ago on Introduction
http://www.techshopdurham.com
or another TechShop near you.
13 years ago on Step 2
I wonder if you should use artwork like that prepared for a CNC PCB milling system for this; in those setups, they just mill lines in the copper to separate conductive areas. It seems like that would require a lot less laser time, since you're removing less of the copper. If you're paying for laser time by the minute, this could really save some money.
13 years ago on Introduction
Cool! What laser cutter did you use? What settings?
Reply 13 years ago on Introduction
Hi Jeff-o, its an ILSM 30W laser with the settings SPEED 30 and POWER 100.