PCB Transfer via Laser Printer - Page 1
Forum section: electronics / beginners

author: David Cutcher CEG
author_rank: Contributor
timestamp: April 17, 2019, 02:14:58 am
content: This is for people who need simple, reliable and easy transfer of their traces onto copper clad.Here in Canada, the classroom chemicals for photo resist transfer were labeled carcinogenic. I showed this method to my colleagues and it was immediately adopted by everybody. With practice, I was able to consistently get .015" lines.To do double sided, just line up some pre-drilled register marks before attaching the paper.See attached, from my book Electronic "Circuits for the Evil Genius" 2nd ed, McGraw HillDavid Cutcher - Certified Evil Genius

author: Psi
author_rank: Super Contributor
timestamp: April 17, 2019, 02:23:18 am
content: I never got photo paper to work that well.Proper laser printer film designed for making PCBs, like press-n-peal blue, always worked great.But i never got photo paper to get anywhere near the quality of press-n-peal blue. 0.2mm was about the limit for it, did a 100TQFP once.Then i discovered elecrow and pcbway

author: David Cutcher CEG
author_rank: Contributor
timestamp: April 17, 2019, 03:25:50 am
content: The dedicated paper is far superior, yes. But at $.25 / sheet, the Photo Quality Ink Jet Paper does a great job.Immediate success nearly guaranteed with .03" (.75mm) even for a beginner.Yes, it does take practice. but I was able to get regularly get a trace between CMOS DIP chip pads and 3 traces down the middle of a 4011 CMOS. But I always tried to keep those super thin lines as short as possible.DC

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2019, 05:15:58 am
content: I think it depends a lot on other variables, I had some success with photo paper but nowhere near as good or consistent as press n peel. The cost of the PnP looks high but a little goes a long way, I cut a piece just big enough for the board I'm making and after ~10 years I'm only on my second package.As far as chemicals being labeled carcinogenic, that's probably thanks to Prop 65 in CA which labels virtually *everything* as carcinogenic. I would not be surprised if that warning is somewhere on the photo paper too.

author: Psi
author_rank: Super Contributor
timestamp: April 17, 2019, 10:52:14 am
content: The way i used press-n-peal blue was to first print what i wanted on an A4 plain paper sheet.Then i made 4 small diagonal cuts into the sheet at the corners of my pcb design within the sheet.I would then cut out a small piece of press-n-peal blue and insert the corners of it through the slits in the plane paper sheet.Then i could put the entire thing into the printer and print on only the small section of press-n-peal blue that i required.It made the stuff last for ages.Ya get a lot of small pcbs out a 5 pack of A4 press-n-peal

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2019, 03:59:50 pm
content: I use a similar technique but instead of cutting slits I just tape the leading edge. I also draw an arrow on the paper before I run it through the printer the first time so I can remember which way to stick it in for the second pass.

author: Jwillis
author_rank: Super Contributor
timestamp: April 17, 2019, 04:55:44 pm
content: I've tried just about every transfer method and the only one that gave the best results was to use the backing from vinyl adhesive signs.Theirs a local shop that makes these signs and I get the backing for free and cut it into 8 x 11 sheets.It doesn't jam in the printer and transfers perfectly every time.Best of all it's free.

author: David Cutcher CEG
author_rank: Contributor
timestamp: April 17, 2019, 05:53:20 pm
content: You've come up with a really cool way of doing this too.I used a T-Shirt press for large sheets, much the way you've used the vulcan press.Thanks for sharing.David Cutcher "Certified Evil Genius"

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2019, 09:05:46 pm
content: That vinyl sign backing is intriguing.

author: tautech
author_rank: Super Contributor
timestamp: April 18, 2019, 08:10:36 am
content: Quote from: David Cutcher CEG on April 17, 2019, 03:25:50 amTip.When you find the transfer medium that works withyourprocesses cut off just enough to comfortably cover the PCB and stick it over the layout on a pre-printed A4 sheet and run it through the printer again.Doing this you only use just what you need and your transfer medium then goes a long way.

author: KL27x
author_rank: Super Contributor
timestamp: April 18, 2019, 08:17:38 am
content: ^Most of my DIY boards fit on a 4"x3" rectangle. You can cut an 8.5 x 11" sheet of paper into 6 equal rectangles, slightly longer than 4" and slightly taller than 3".I open a new package of Pulsar and cut 10 sheets into 60 of these little rectangles with a guillotine.I print 4 brackets slightly larger than these rectangles onto a stack of printer paper.Lay a bunch of strips of kapton tape onto a cutting board, in parallel. Slice them into 1" length with a small knife. Stick the square onto the target with two pieces of tape, in either upper corner of the rectangle.Each time I spend an hour prepping the copper clad, transferring the resist, and etching up to a 4 x 3" board, the cost of the Pulsar is twenty five measly cents. If you think Pulsar is expensive, you don't value your time.The PnP Blue isn't bad, either, but I prefer the Pulsar.

author: Psi
author_rank: Super Contributor
timestamp: April 18, 2019, 08:47:21 am
content: Quote from: james_s on April 17, 2019, 03:59:50 pmI did consider using tape but i figured it would probably melt when going through the fuser. Then stick to everything and ruin the printer, so i never tired it.

author: KL27x
author_rank: Super Contributor
timestamp: April 18, 2019, 09:01:27 am
content: Kapton tape or paper tape. dont use cello tape.

author: KL27x
author_rank: Super Contributor
timestamp: April 18, 2019, 09:25:05 am
content: QuoteI get at least 8x 8 mil traces down the middle of a standard DIP without even optimizing. Just routing free hand, uneven, and then doing a DRC to check for minimum 8 mil clearance. I can get probably 9 if I take the time to space them evenly. With oval through hole pads, I can run 2 traces between pads. But I don't use any DIP IC's for the last 5 years. This isn't "pushing it." If it takes special attention, I avoid doing it. This is business as usual.QuoteI often make my traces much bigger than 8 mil. If it doesn't really matter for the layout, I tend to make the traces bigger, even on factory ordered boards. Actually it makes it easier. If you use 8 mil traces but the IC has wider spacing, then you "have to" bunch your traces together and then fan them out again.* But when I use an 8 mil trace that isn't carrying a high current, I make it 8 mil all the way. Making the trace thinner in only one spot makes it look funny, and I have the impression it increases the chance that the short thin section overetches.*The only thing I try to avoid is running a skinny 8 mil trace all by itself with nothing around it. This is one of the things that can be iffy. Ground pours take care of that problem. This is also why you "have to" bunch skinny traces together and fan them back out. Else you get slivers of ground pour between them, anyway. And if you leave them too widely spaced with blank space between them, bysay increasing your trace clearances, this can etch funny. Bigger traces, you can use any clearance you want. But IME, when your traces get smaller than 12, you want the clearance to be roughly the same size as the trace thickness at most, but you can make them smaller if you want, down to w/e resolution you can get with your methods and etchant.It's a strange thing where you start out making giant boards with fat traces with giant clearances. But as you shrink your clearances, the etch comes out better. And you can get way more stuff in a smaller space. And getting the board done in a smaller space also increases your yield, because it's less area for an error. Experimenting with reducing clearances, you may find this can be more important to the yield than the trace width, and the fat traces are no longer necessary. It may be initially uncomfortable to solder a board with tight clearances, but you can use larger clearances just around the pads without compromising the results by much. Heck, it looks "bad" at first, like it will be harder to detect bridges. But thinner clearances etch faster and cleaner and you don't have to look as hard. Higher consistency and clean edges means less (or even no) inspection. I really don't but glance at a board and call it good. If you etch a single-sided board on double-sided copper, you know the blank side not only takes forever to etch, but one area of the blank side becomes clear way before the last bit etches away. Large enough clearance, and that also slows down and "unevens" the etching and can lead to chewy traces.I have heard some people using toner transfer do 12/18... 12 is fine to use oversize clearance. I think these peeps need extra clearance because they are either fattening their traces during the transfer and/or they are using fuzzy paper that leaves fibers. If your process and etchant are up to snuff, once you get comfortable with looking at and assembling boards with tight clearances, the process goes to the next level and is extremely reliable. I haven't have to repair or redo a board in probably 5 years.

author: Wimberleytech
author_rank: Super Contributor
timestamp: April 18, 2019, 11:56:47 am
content: Quote from: james_s on April 17, 2019, 05:15:58 amImagine the billions of gallons of carcinogenic ink wasted to print on every product: the California Disclaimer. The land of fruits and nuts.

author: Wimberleytech
author_rank: Super Contributor
timestamp: April 18, 2019, 12:11:34 pm
content: I use transfer paper purchased from China on ebay.I also use the arts/crafts transfer film on top of the transferred image on the pcb. This has significant improvement!Transfer is done using a laminatorEtch using ferric chloride.My layout designs attempt to minimize and keep uniform, all etched tracks. This reduces consumption of the etchant and makes it easier to do successful narrow traces.Sometimes I heat the etchant to speed up the process, but not always.I have tried photo paper, glossy magazines, etc., to varying success. My current method using the chinese stuff is consistent and repeatable.I use HP P1102 for my printing. I think current cartridge is not HP brand, however.Before adopting the transfer film, I experimented with acetone vapor to melt the trace on the pcb for better coverage. Hit and miss...transfer film is better.

author: Psi
author_rank: Super Contributor
timestamp: April 18, 2019, 12:51:48 pm
content: Quote from: Wimberleytech on April 18, 2019, 11:56:47 amIf i owned a bottled water company i would make a version of my bottled water that had the California Carcinogenic warning label on it and sell that version exclusively in California.True it wouldn't sell very well, but to hell with it. I'd do it just to poke fun at the stupidity of that California law.

author: madires
author_rank: Super Contributor
timestamp: April 18, 2019, 01:28:02 pm
content: Quote from: David Cutcher CEG on April 17, 2019, 02:14:58 amNaOH is everywhere, it's even used for food preparation.

author: james_s
author_rank: Super Contributor
timestamp: April 18, 2019, 03:50:23 pm
content: Quote from: Psi on April 18, 2019, 08:47:21 amI use ordinary scotch tape, it works fine, I've done it hundreds of times and never had the tape melt or gum anything up, Xerox and HP printers. I think the tape has too much thermal mass for the time it spends in the fuser.

author: james_s
author_rank: Super Contributor
timestamp: April 18, 2019, 03:59:38 pm
content: Quote from: Wimberleytech on April 18, 2019, 11:56:47 amThe law was created based on good intentions but there's that old saying about the road to hell. The problem is that it's written in such a way that makes it inevitable that nearly everything will end up on that list because there's no penalty for a false positive but potentially huge penalties for a false negative. It also doesn't take quantity into account and at high enough levels even the most benign substances can kill you or possibly cause cancer. It was doomed to failure from the very start, a warning that is on everything tells you nothing.For what it's worth, I'm pretty sure there was one of those California cancer warnings on my printer.

author: KL27x
author_rank: Super Contributor
timestamp: April 18, 2019, 11:51:56 pm
content: QuoteGood to know. I probably won't chance it, in case of a jam or something, and I always have kapton tape anyhow.I ran a plastic printable envelope through a laser printer, knowing it was a risk. But I thought I could probably unjam it, if anything went wrong. What's the worst that can happen? Pick out some bits of melted polypropylene? Well, landfill. That's the worst case.

author: austfox
author_rank: Regular Contributor
timestamp: April 19, 2019, 08:05:02 am
content: Quote from: David Cutcher CEG on April 17, 2019, 02:14:58 amThanks for the great tutorial.Just change the word ‘ink’ to ‘toner’ above Figure E-3 for future reprints.

author: james_s
author_rank: Super Contributor
timestamp: April 19, 2019, 06:33:51 pm
content: I have one of those evil genius books around here somewhere, it's cool to bump into an author of a book I've actually read. Now I'll have to dig it out and see which one it is.

author: David Cutcher CEG
author_rank: Contributor
timestamp: April 20, 2019, 12:17:52 am
content: I'm #3 in the series.Electronic Circuits for the Evil Genius.Setting up a course on Udemy.com, should have it up and running July 1st.davidacutcher@gmail.com