Introduction: Making Flexible PCBs With a Laser Jet Printer or Copier

You can make flexible PCBs on the cheap using a laserjet printer or copier- basically anything that uses toner. They have pretty good accuracy, but I wouldn't trust it for anything smaller than an 0805 SMD part, though I have done down to 0804. They're great for making LED boards that you can iron onto fabric! Since the Pyralux is copper coated Kapton (Kapton is a heat-resistive plastic) you can even solder to them once they're ironed on.

You'll need:
-Pyralux, AKA copper-clad kapton. I got mine from DuPont- I wrote them saying I was a researcher and they sent me a bunch. Maybe you'll have the same luck; otherwise eBay works. 
-Brillo Pad
-Rubbing alchohol
-Ferric Chloride or other etchant (this is writing assuming you're using Ferric chloride- still conveniently sold at Radio Shack)
-Laser printer or copier 
-some sort of graphics program
-nitrile or latex gloves
-SMD parts (these do not work with through hole components)

Step 1: First, Prepare Your File in AI (or Any Other Graphics Program)

I made a bunch of different sizes, as I was experimenting. You can do whatever you want. 

Step 2: Prepare Your Pyralux

Get some gloves and cut your pyralux into the size of paper you're going to be printing. I used standard letter sized paper. If your pyralux piece is small, tape it to a piece of paper. I suggest taking a piece of plain paper, writing 'up' and an arrow pointing towards the printer (so you know which way to put it in) doing a test print, then taping the pyralux over the correct area. Bam. 
To prepare your pyralux, first take some rubbing alcohol and rub down the copper side. You must remove all thumbprints and hand oils. Once you've done that, take your brillo pad, and gently but firmly scuff the entire copper side. The pressure should be enough that you see the copper being marked, but not enough to crinkle it. Don't crinkle it. 
Once more, wipe down with the alcohol to remove the copper dust you just created. Wipe with a paper towel. set aside and DO NOT TOUCH AGAIN WITH BARE HANDS. From now until after you develop, don't touch it. Just...don't. 

Step 3: Print!

Place the Pyralux into the printer or copier(with your gloves on!). Make sure it's as smooth as possible, and also check to make sure the Kinko's attendant is busy with Flappy Birds or 2048 or something. 
If you're on a copier, set the print to extra dark. Lots of toner= better resistive in the etching stage.
Hit go, or copy, or EXECUTE or whatever.
Do a little dance (with your gloves on!) continue to try to not get kicked out of Kinko's. 
When it comes out the other side..take it out (with your gloves on!) and place it in a bag if you're in good 'ol Kinkos, or just asside if you're abusing your own printer. 

Step 4: Etch!

Time to etch your boards. I recomend the wiping method rather than the soaking method. Here's a link. Don't do this at kinkos.

be sure to properly dispose of your Ferric Chloride. 

Step 5: Kabloomers! You Have Boards!

Here are my boards. In this photo I have cut them into strips. That paper behind the boards is double-sided interfacing, which adds an iron-on adhesive to the boards. Yay! 

I originally wrote this up for Check it out and other stuff I did/do over there!


DoctorWizard (author)2016-02-11

Dupont will send you a 6 sq ft (24" X 36") FREE SAMPLE. Enough to make lots of boards. I cut it into smaller sheets with an old skool paper cutter.

fkeel (author)2015-01-06

how does the ink-jet process compare to using a solid state printer?

cromas (author)2015-01-02

What's the linen-looking patterning visible on the copper here? Is that a weak transfer?

brianfroelund (author)2014-03-28

This is indeed a very nice way of making flexible circuit's exactly like the guide doing it using a solid ink printer is also very nice. The problem however is that pyralux just isn't easily obtainable.

Do you guys have any alternative ideas on how to make something similar to the pyralux sheet's but is easier to obtain.

Kapton tape and Coper foil is both easy and cheap on ebay. You guys have knowledge on what adhesive one would use to bond them together? I'm quite sure that adhesive on the kapton tape is not gonna survive any kind of etching.

kgroce1 (author)brianfroelund2014-12-17

Adafruit has some...

NateOstrye (author)2014-03-21

Fantastic post! I've actually use this process for a couple years now, and I've etched a whole lot of boards with a variety of results. Overall, this has become my favorite DIY etching process. Its easier and faster than the iron-on transfer method. Here's a few tips I've figured out along the way that I've actually been dying to share recently.

1. Solid Ink printers can also be used instead of toner printers. I use a Xerox 8550, and the results are fantastic. You can get a used one on Ebay that won't break the bank. I've also found that I can print a test copy on paper, then cut my copper to only fit that print zone, then run it back through (I set my printer for photo quality and tell it I'm using transparency material, wonderfully solid masks). Kinko's was forcing me to cut my sheets to 8.5 x 11 and I was wasting tons of material.

2. If you're using a sponge to help speed the etch, blot with it, don't swipe or scrub. This is especially true if you're using ferric chloride. Swiping would eventually rub the mask off for me, and with room temperature ferric chloride, this becomes a major issue with traces less than about .030". Blotting helps fix this issue, although not a complete cure. If you are using this method, I highly recommend getting a pyrex pan and setting it on top of a heating pad to warm your ferric chloride. Ferric chloride works significantly faster when its warm, which cuts down on the amount of sponging, and therefore decreases the chances of knocking off your mask.

3. Cupric Chloride in an air agitated bath works better than ferric chloride and a sponge. Save yourself the headache of scrubbing PCB's and get an aquarium pump, hose, and an air stone. The Cupric Chloride can be easily made (there's instructions on this site) and its REUSABLE pretty much indefinitely. Just recharge it with the aquarium pump! No more buying etch solution all the time, and I haven't seen my old friends at the hazardous waste disposal center in months! It also has a huge benefit that it doesn't attack the toner/mask nearly as badly as ferric chloride. It does smell worse though, so, ventilate (which you should do anyway with ferric chloride).

4. Ditch the steel wool, go for very high grit sandpaper. I had too many problems with loose steel wool pieces getting into my stuff. They either got into the printer or etch bath or messed up my masked areas. You can accomplish the same thing with some 600 grit sandpaper and light sanding. I had several boards that I spent a bunch of time patching traces because a sliver of wool had made its way into the mask then fell off, etched right through my trace! I never can seem to get rid of ALL of the steel wool mess. Either way, just like you said, keep that final surface CLEAN before printing on it.

5. Keep a big box of baking soda on hand. Both cupric chloride and ferric chloride can be neutralized with baking soda. It helps to pull a board out of the etch and douse it with baking soda before rinsing. It will stop the etch as well as neutralize the majority of what goes down the drain. Also, its good to have on hand for spills. Cupric Chloride reacts more quickly than ferric chloride, the ferric chloride tries to form little balls like when you add flour to water.

6. Acetone removes the toner/mask faster than Denatured or rubbing alcohol. I usually remove the mask with acetone, then give a final cleaning with denatured alcohol before beginning work.

7. Tin your traces as quickly as possible after etching. The exposed copper will begin to tarnish very quickly in most environments. I use an flux pen and standard solder just to tin the areas I will need to solder later. Rinse the flux residue with denatured alcohol followed by clean water. Having a surface that flows right with the solder helps a ton with SMT.

8. This material is cool because its flexible, but it provides very little structural rigidity. If you have wire leads or pieces that will be moving around often near their solder joint, you will want to add extra structure. Hot glue works surprisingly well to either attach a solid backing material or to secure wire leads. Either way, take your flex points away from the pcb.

9. Mask off excess copper areas instead of trying to etch them off. Instead of trying to wait to etch away massive tracts of open space, try to think about designing your PCB so that your are only etching away small amounts of copper. This will save you time and etch solution.

10. Pyralux can be found on Ebay on a steady basis. Its rarely available in 8.5 x 11 size, you just have to take what you can get, but its still pretty cheap.

11. You CAN make through hole work! I do it all the time! You just have to think of things backwards in your head, which isn't usually a problem with resistors and such, but can be tricky with IC's. Using a standard PCB layout program (I use the free software from ExpressPCB with fine results) just drop the component onto the layout, but realize that you will be placing the physical component on the BACKSIDE of the board. This might get your brain knotted up for bigger parts, but its not too terrible to track with an 8 pin DIP. Once you've etched your board, use a push pin to poke a hole through the material, going from the side you will mount the component on. Fold the legs over onto the trace and solder! I try to avoid this method if I can in favor of SMT because its added work, but sometimes you don't have a choice.

I hope these tips help! WIth my current setup, I can print, etch, clean, and tin an entire PCB in under an hour with traces down to .010". Fantastic for DIY work! Great post!

audreyobscura (author)2014-03-20



You're rad!

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