Make Circuit Boards With Lasers

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About: I like banjos, and whiskey in a jar. My favorite meal is brunch. In my free time, I make things, break things (usually trying to fix them), and play with electronics. In my day job, I'm a science journalist.

A homemade circuit board is only as good as the mask you put onto it. No matter what method you use to do the actual etching, you still need to stick an image of your circuit onto the board, and make sure it leaves crisp, clean, solid traces behind when the exposed copper dissolves. That's harder than it sounds.

There are lots of ways to add a mask to copper board—permanent markers, vinyl stickers, toner transfer, and more. Each one gives decent results, but can be messy and/or time consuming..

The good news? If you have access to a laser cutter or engraver, there's a MUCH easier way! With some black spray paint and an image of your board, the precision of a laser will make a professional-quality mask in just a few minutes.

You'll need:

  • A completed single-sided circuit board design (I used Autodesk Eagle to make mine.)
  • Access to a laser cutter or engraver
  • 1 package copper clad board (single sided)
  • 1 can black spray paint, matte or flat finish
  • latex gloves or rubber dish gloves (optional)

Step 1: Export Your Board Layout As a PNG File.

Export your circuit design as a PNG file from whatever software you used. Be sure it's ACTUAL SIZE, not scaled larger or smaller, so your components fit. You can check by printing the image on regular paper, and poking components through the holes - if the parts fit, you're in good shape.

If you used Eagle like I did, here's a mini tutorial on how to export:

  1. Click on the "layer settings" button. (looks like three multicolor squares).
  2. Make sure that ONLY the traces and pads on bottom of the board are displayed. This is the stuff that you want to physically see etched on your board. Usually this will be layer 16 ("Bottom"), 17 ("Pads"), 18 ("Vias"), and 20 ("Dimension)".
  3. Under the "file" menu, select "export", then "image".
  4. Set resolution to 1200 dpi, and BE SURE to select "monochrome." Give the file a name, and save it.
  5. Finally, INVERT THE COLORS of your file. Anything that was black should now be white, and vice-versa. You can do this in most image editing software (for instance, there's a one-click "invert" command in photoshop or GIMP.
  6. Save the image as a PNG file.

Step 2: Spraypaint the Blank PCB

Next, prepare the blank copper clad boards. I didn't take many photos of this step, but it's pretty straightforward.

Wipe down a few blank boards with acetone to clean off any oil from your fingers. Wait for it to dry, then lay them down on a piece of clean scrap paper. Apply a 2-3 coats of black spray paint to each one. Go easy - a few light layers is better than one thick one. You want the paint to go on as evenly (and dust-free) as possible, with no drips or runs.

Ultimately, we'll be using the laser cutter to burn off the paint in the spots where you want to etch the copper... so the more uniform the surface, the better the result.

Step 3: Burn in Circuit Design Using Laser Cutter

Pew pew! Time for lasers!

  1. Load the INVERTED COLOR PNG file into your laser cutter's control software.
  2. Set up the software to etch rather than cut. The laser remove anything that's black in the image, and will leave the white space (the stuff that will become your mask).
  3. Lay one of the painted copper boards into the cutter bed, with the black side facing up.
  4. Make sure to set things up so the laser doesn't burn past the edge of your board. I found it helpful to push the board into the very top left corner of the laser cutter's platform, and nudge it against the ruler guides on the cutter's platform. Your cutter may be different, though.
  5. Etch away!

You may have to play with the settings a bit to get this to etch correctly, so it's helpful to paint a couple of extra boards to use for trial runs. Lasering off the paint doesn't remove any of the copper, so you can always go strip it and re-coat for another try. Just make sure your cutter has a good ventilation fan.

Step 4: Etch Away!

Now you're ready to etch! Use whatever method you want—ferric chloride, ammonium persulfate, etc. If you don't want to deal with gnarly chemicals, you can also etch more safely with common kitchen supplies. (Check out my other instructable on how to do that here!)

When you're done, clean off any remaining paint with acetone, drill some holes, and you're all set to solder components. Happy etching!

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    23 Discussions

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    RonH11

    3 months ago

    Just wondering why you wouldn't just use the laser to raster off the copper you didn't want leaving the circuit behind?

    1 reply
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    videoschmideoRonH11

    Reply 3 months ago

    That would be AMAZING, but sadly you need an industrial-level laser to pull that off. Most laser cutters won't be able to etch through the copper, so I did the next best thing....

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    techydiy

    3 months ago

    I have used a similar method a few times, exporting the gcode and using isolation routing. I found that I had to clean invisible paint residue from the board before etching. I think the quality of the laser must make a significant difference. Anyway good job, thanks.

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    videoschmideotechydiy

    Reply 3 months ago

    yeah, you definitely have to play with the settings a bit to get a good etch - but for the bits of residue that were left, I found that lightly rubbing with a dry paper towel did the job nicely - it has just enough roughness to scuff off the residue without taking off much of the other paint.

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    hardray

    Question 3 months ago

    Doesn't work.
    Wich finnish do you use?

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    throbscottle

    3 months ago

    Clever technique for those with a laser cutter, quite an impressive idea.

    Heads up about acetone though, it can actually leave a greasy residue, which is not good for making paint stick. Better to clean again with alcohol after the acetone. Better yet to follow full PCB cleaning procedure, more hassle but you do get a decent surface.

    2 replies
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    videoschmideothrobscottle

    Reply 3 months ago

    Didn’t realize that about the acetone - thanks for the heads up! And yeah, full cleaning procedure would probably give better results... I just got lazy. ;)

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    throbscottlevideoschmideo

    Reply 3 months ago

    It's one piece of information I always try to share, having been caused wasted hours + materials myself by it. Acetone is great for cleaning off all kinds of stuff, but for that one caveat.

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    Wragie

    Question 3 months ago

    Very nice! Got my vote. Only one point to clarify is type and brand of black paint. If any brands will make a difference and if any type does as well. And definitely your laser needs to be focused to the nth degree (and the table level) to max out the detail.

    1 answer
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    videoschmideoWragie

    Answer 3 months ago

    Good point! I’ll try to find the can if it’s still lying around. I don’t really think the brand of paint matters much, though, as long as it’s matte finish and the coats are even. You’ll likely need to fine-tune the laser intensity/frequency with each new batch of boards anyway.

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    videoschmideoWannaDuino

    Reply 3 months ago

    They’re definitely great - their boards are affordable, and their design interface is awesome for simple layouts. For one-off projects or rapid prototyping, though, shipping can be expensive (25-30 bucks) and each iteration takes a while to arrive. Making your own board is more work, but you can iterate in a matter of hours instead of days or weeks. Plus it’s sooooooo satisfying in the end...

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    n4mwdWannaDuino

    Reply 3 months ago

    With the right tools and equipment its usually faster to make them yourself. However, when you figure the cost of the bare board, the cost of whatever mask you use, and the cost of chemicals, the chinese board shops are only slightly more than that and deliver, usually within 2 weeks, a superior board with 2 sided solder mask, plate through holes, and 2 sided silkscreen. I personally like to make the first board myself. That way I'm not waiting 2 weeks to find out I made a bad mistake.

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    n4mwd

    Question 3 months ago

    Does the laser exposed paint simply go up in smoke or is there an issue with ashes getting in the way of the laser's next pass?

    1 answer
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    videoschmideon4mwd

    Answer 3 months ago

    I found it mostly just vaporizes with the right settings - if there’s any residue left, it’s pretty minimal, so a quick wipe with a dry paper towel afterwards usually takes it right off.

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    jezuita

    3 months ago

    I tried experiment with this few months ago and the result is not so good for thin lines and small holes and pads. Little bit better is it if you use vinyl sticker instead spray. You must set accurate laser power and turn off bi-direction. Removing vinyl is quick and easy with knife.

    3 replies
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    crosendahljezuita

    Reply 3 months ago

    Don't cut vinyl with your laser cutter! Cutting PVC materials creates chlorine gas - highly toxic.

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    videoschmideojezuita

    Reply 3 months ago

    Hmm. The thin lines I was able to get with this method turned out pretty well—maybe it was a settings issue on your laser cutter? You definitely need to have the etch time and intensity dialed in on the laser cutter. To get mine right, I made a test file that used different settings on a single board, which really helped find the right combination of settings quickly.

    I've never tried the vinyl sticker mask—did you mean putting a vinyl sticker over the whole copper board, then cutting out your circuit from that vinyl sheet using the laser cutter? That's not a bad idea - might have to try that sometime. How do you ensure that the really small lines you cut out won't warp or peel up when you put them into the etchant, though?

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    kvcumminsvideoschmideo

    Reply 3 months ago

    One way would be to jumble the order of operations. Clean the board->Apply Vinyl->Laser Cut Mask->Remove Copper Trace Mask->Paint Board->Remove Mask->Etch->Profit(?)

    And upon further reflection, you would actually cut the vinyl sticker before applying it to the board, then remove the unneeded portions of the mask. I just remembered a friend who made a bunch of nice beer mugs using vinyl masks, since he had access to the whole setup as an ordinance tech for the USAF (you know, the guys they keep in the bunker on the FAR side of the airfield). And I kinda doubt they wrangle ordinance into any sort of cutting device just to get a stencil...

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    t.rohner

    3 months ago on Step 4

    Cool
    Finally someone with a Trotec Laser.