DIY Toner Transfer Paper (cheap and easy))

[mvs sarma]

Yes I think you are right.

There is a something I read about using silk screening but with out poking holes in it but instead oil to wet the paper set it up on the photo resist and put it in the sun for 15 minutes. I wonder if that same concept would work with PC boards. I have plenty of old photo resist boards. This gets away from the vagaries of heat (yes the toner fuses at 275 to 290 °F and good luck finding anything that can control that tightly) and pressures that can move the traces (doubled sided trouble).

I've always liked the photo resist method and I wonder if going through the pin holed toner traces and through the oiled up paper that it fills in those pesky pin holes. Yep I think it is high time to try that.

Whether the refurbished Toner cartridges like HP88A etc as in HP P1007 laser printer,would suit the TTS method? I suspect that they might not use Plastic powder

 

[Angelgroove]

No need for plastics

Whether the refurbished Toner cartridges like HP88A etc as in HP P1007 laser printer,would suit the TTS method? I suspect that they might not use Plastic powder

TTS? I take it means thermal toner system? If you are referring to toners from my previous post all toners still use plastics in their formulations. Otherwise what are you transferring? Carbon dust is not sticky.

With a photo method there is no transfer. What occurs is dark areas create a positive photo resist method.

What I have tested so far with all these iron heated methods, and what I have seen is the inability to maintain thin lines. I have proof of that even at very low temperatures. I think what happens is the surface tension at fusing temps are lower in thin lines than thick lines. To date the best I can do is .025" traces where consistency is met. With that size you can kiss goodbye your ground planes because of too many choke points. So there is the trade off and no wonder everyone is using no ground planes on the top layer. In these days of megahertz conditions ground planes are needed to quell the electronic leakage. Another issue I see here with the heated systems are the films look heated and are unacceptable for a solder mask or a silk screen where you might have a graphic like a bar code.

The photo method uses no heat and no pressure. Pin holes could potentially be mitigated by using white paper that is optically clear with using an oil on the paper. Because of the oiled paper too, it adds an extra dimension that seals up the pin holes, at least that is my theory. It means that plain paper is used, and you have no care if it is toner or inkjet (as long as it is not oil solvent). The draw backs are increased cost with a developer and the resist. The upside is maintaining very precise registration and maintaining very precise thin lines probably on the order of hairlines or .25 points.

I will try this photo method and see what gives here. If it works for silkscreening, which do not tolerate pin holes, it should work with PC board manufacture. If so with a little higher cost you can have it all.

 

[Angelgroove]

Thermal transfer using toner for PCB test

Using what rudimentary tools I have I did a test to see where the temp of the board need to be and what heat setting that is. Using a Fluke multimeter with a thermocouple next to the back copper of the board (see attachment) while heating in a press (very little pressure only enough to keep the thermocouple in place) I was able after several iterations starting at high heat (280°F) down to low heat (220°F) at the back of the board or another words board temp, I came to a point where bonding occurs and fusion is maintained without melting the plastic (very important). I used Puslar's transfer paper and am very pleased in how it just rolls off in water.

Please see the attached file for pictures of the test with various line widths and the rated temperature that should achieve repeatable results. The setting of the press is equivalent to the silk setting of your iron. If you use a higher temp your time to heat is lower. This is like any other heat process it is getting the substrate up to temperature where bonding can occur. It has nothing to do with face temperature. Nothing sticks to cold substrates in a heat transfer process.

 

[3v0]

Just a note:

When you do tests with fine lines you need to inspect the toner on the transfer paper after printing. Some printers are better then others at reproducing the fine lines especialy on the Pulsar paper which is slick. If there it too little toner it might tend to bead and break the line.

In general I do not use traces under .010".

3v0

 

[Angelgroove]

When you do tests with fine lines you need to inspect the toner on the transfer paper after printing. Some printers are better then others at reproducing the fine lines especialy on the Pulsar paper which is slick. If there it too little toner it might tend to bead and break the line.

I use what I have, recognizing some printers are not so great. I use a new Samsung printer and had to get three of these units before I came up with one that was working to spec. HP is no different and because you might have a great printer buying one might not achieve the same results.

I sweep everything into vector format into Illustrator and reset all the black lines to fire all four colors. That way I set all the colors and the black to 5 density with results being very good using CMYK set to 255 in each color band. My personal feeling is no matter what printer you use the minimum line width for the thermal process is about .020" for reliable time after time repeatability and if you have the time and the resources to test out the best printer for this process you probably can get to your .010" spec. Anything smaller than that and you are risking what you say with beading etc., and I think it also has to do with the grain size of all the particles in the toner and who has that info.

 

[3v0]

My personal feeling is no matter what printer you use the minimum line width for the thermal process is about .020" for reliable time after time repeatability

I do not do production quantity or large PCBs. I have done a good number of PCBs using the pulsar system and seldom use a trace larger then .016 for anything but power and gnd. Most often I route signals with .016 or .012 and drop down to .012 or .010 to squeeze between pads. Unless I goof I get good results with no touchup required.

I use an aprox $100 HP1020 B/W printer with an HP cartridge.
If you are not using a laminator you should give one a try. You are trying way too hard for too little results.

3v0

 

[DirtyLude]

My personal feeling is no matter what printer you use the minimum line width for the thermal process is about .020" for reliable time after time repeatability and if you have the time and the resources to test out the best printer for this process you probably can get to your .010" spec. Anything smaller than that and you are risking what you say with beading etc., and I think it also has to do with the grain size of all the particles in the toner and who has that info.

Have you read the rest of this thread? Plenty of people easily get 10mil traces using TT (Toner Transfer). Many people can get much less than that. 10mil is my standard width, but I've done 6mil without much problem and can likely go lower. I use regular photo paper and an iron.

You might want to do a search of the other dozen or so multi page discussions on Toner Transfer and Photo sensitive PCB discussions. There's a lot here that has already been tried and alot of methods. Not even taking into account the much larger discussions on the Homebrew PCB Yahoo mailing list.

 

[Sceadwian]

Alas Dirtylude, there are a great many things that I can't do because I live in a small apartment right now with an even smaller area all my own that has to be kept relatively neat. There's about a billion projects that I have on hold right now. I should be in a house by next year, I'm looking forward to that and a decent work bench or two.

 

[DirtyLude]

Well, 0.5mm is not that much smaller than .025"; about 20%. It's not that it can't be made smaller it's that these bits get ever more unreliable as they get smaller, not just breakages, but they get duller quicker. Another thing is the wire really helps to be slightly friction fit like it is now. I think this is a good compromise between size and reliability. Also I don't need any smaller than this on home made PCB's. The only thing I would really want to work on is see if I can get these vias flat so they can go underneath chips. I might try a file on another board just to see if I can get them flat, reliably.

 

[Sceadwian]

I have a small piece of hobby padded sandpaper that's useful for that kind of thing. Ultra fine thin sandpaper attached to a foam pad, conforms but still sands, can be cut with scissors into almost any shape. It's hard to work on that kind of scale, though I would never try to use a non-conforming hard file

 

[DirtyLude]

The point of it is to make the bumps flat. Using sandpaper will sand everything whether it's needed or not and the thin traces can't take too much sanding. It seems pretty clear to me. I'll try it out and show the results.

 

[Angelgroove]

Success with the Pulsar system

Finally after many iterations and having to change things around to accommodate this heating methodology. Next week I will do a comparison method with photo resist and see how it compares time wise, cost wise etc...

To those that claim they can get a 10 mil line I need to see that. While I believe you can get a 10 mil line over short transitions I really doubt with this method you get easy repeatable results. Additionally Pulsars paper simply glide off and any other paper you have to scrub off the residue. I do not work for Pulsar and fell into their product with research into new methods to make PC boards. Even at very low heat, distortions still occur that again I do not see who can get reliably anything less that .020". Here is my shot at it with those .020" gaps and traces. Notice in the in the corner holes the distance to the ground plane to the pad in the thermal pad arraignment. This is 10 mils and as you can see it has a tough time registering accurately and shorts can occur. Here it does not matter this is done so the the soldering process does not get a cold joint. I would like to thank Pulsar for all their methodologies and advice. All the registration from side to side is perfect thanks to a process on Pulsars website. Please note something weird is going on with my camera as the pictures seem out of whack (no alignment back to front). I have no idea what it is as the board I have here lines up to a .010" tolerance. Not bad for home grown. The proof will be in the component insertion.

The laser printer is a Samsung color and I get all four CMYK guns saturating the density which leads me to believe a color system is superior in density to any mono system because you are putting on 4 times the toner. I use Adobe Illustrator to accomplish the CMYK black and to do the accurate page make up. I used Express PCB to do the layout.

The next task is to drill the board out and start to populate it.

Again thank you Pulsar with a stellar product with a repeatable and reliable system.

You know anyone living in an apartment who cannot actually make these boards because of health concerns (and rightly so!) The process of page make up to getting to printing is a lengthy one. I would get good at using ExpressPCB and Illustrator to make the pages up. I would then do the under the radar thing of advertising your services. I can show anyone how to do that if you like. The reason I say that is because I think we are in the beginnings of a home brew hobby related Renaissance with PIC microcontrollers and the ability to make you own PC boards. I can see already three to four different job postings right now.

 

[DirtyLude]

To those that claim they can get a 10 mil line I need to see that. While I believe you can get a 10 mil line over short transitions I really doubt with this method you get easy repeatable results.

From this same thread.

10 mils
https://www.electro-tech-online.com...ansfer-paper-cheap-and-easy.94601/#post807608
https://www.electro-tech-online.com...ansfer-paper-cheap-and-easy.94601/#post771932

10 mils using Pulsar with steps
https://www.electro-tech-online.com...ansfer-paper-cheap-and-easy.94601/#post760928

8mils
https://www.electro-tech-online.com/threads/ethernet-for-pics-using-enc28j60.97291/#post787489
8mils close up
https://www.electro-tech-online.com/threads/etching-circuit-boards.90381/#post722588

3v0 has an example somewhere, I can't find it now, though.

Again thank you Pulsar with a stellar product with a repeatable and reliable system.

You say that, but you can't get it to work. I don't consider min 20mil traces to be working as it means most of the chips I work with would be unusable. I would suggest getting help from the Pulsar guy.

 

[mramos1]

You say that, but you can't get it to work. I don't consider min 20mil traces to be working as it means most of the chips I work with would be unusable. I would suggest getting help from the Pulsar guy.

I agree, those are monster traces. I will stick with the picture paper.

The reason I say that is because I think we are in the beginnings of a home brew hobby related Renaissance with PIC microcontrollers and the ability to make you own PC boards. I can see already three to four different job postings right now.

Far as toner transfer PCBs and PIC chips at home. I have been doing it for many years. My now 20 year old son took a servo driven robot in for a show and tell when he was maybe 7 or 8. Old 1684 PIC chip ran it, used ferric chloride back then.

 

[3v0]

There are some images on this post but I am not sure they are the ones you were thinking of.

 

[Angelgroove]

Some more thoughts

Two things now have come up.

One the heat required to do these transfers while okay for the hobby field are not so great for any other venue. Mainly the heat stress put into the copper to laminate layer. This glue is only stable to about 350°F before you rip out vias with the drills or worse yet you lose a single pad when you solder. This is why the industry makes it with a photo resist which I am trying soon.

The other is a solder mask. The toner being what it is is susceptible to alcohol. That means cleaning the board post assembly the toner will fail under a tough scrub needed to remove flux. I know that some say do not remove the flux, I simply disagree. So again the solder mask or any silkscreen needs to be done with a silkscreen process and not an iron on. You also get better registration because you can see thought the screen to properly place the board before you spread the paint. Again all cold processes and you have not stressed out the board.

I think this process has come along way. I see people here have done a great job refining down their process. I will post next week my findings on a photoprocess. My goals are to find the cheapest "home brew" one off method while being able to see great looking traces down to 3 mils and maybe even smaller.

 

[3v0]

Most PCB stock does not have a problem with the toner transfer method. I have one batch that likes to shed traces but that may or may not be related to the heat.

Solder masks are nice but you can do without them. Many a QFP has been soldered to a DIY PCB without a mask. Liquid solder beads up and heads for the metal.

If you want to do a toner solder mask use a flux that can be cleaned with soap and water and a tooth brush.

3v0

 

[DirtyLude]

Not to be negative, but like somebody mentioned before, this subject has been experimented on for years. If you think you have something new to add, go through the Homebrew mailing list, and check out the archives to see what other people have tried.

**broken link removed**

 

[Angelgroove]

New photo based board

My first attempt did not have the exposure times right but since it was exposed I developed it anyway and etched it. It includes 1 to 6 mil traces. The one mil will not work, the 2 mil is flaky, the 3 mil is fine, and the 6 mil no problem.

I will post a compete report later as I perfect the timing. Twice the cost, about the same time to etch, better control of the registration and line widths, and no heat into the board.

 

[Angelgroove]

10 mils
DIY Toner Transfer Paper (cheap and easy))
DIY Toner Transfer Paper (cheap and easy))

10 mils using Pulsar with steps
DIY Toner Transfer Paper (cheap and easy))

8mils
Ethernet for PICs using ENC28J60
8mils close up
etching circuit boards

Mark,

You showed me three examples of 20 mil traces. There is no components with 10 or 8 mil pads and all these traces look to be the same size as the pads so again .020" is the minimum reasonable size for thermal transfer, which is the width of the smallest pads. I have included a photo of what I am talking about. This is a snapshot of ExpressPCB with three of the smallest components and the smallest pads. The pads line up nicely with 20 mil traces. Do you disagree? can you prove to me where your 10 mil traces are again. And no those also are not 8 mil traces. Again the smallest pad is 24 mil. so your traces should be much smaller than the smallest pad.

The good news is the photo transfer method just using the sun and the same laser output with Pulsars foil can achieve 6 mils without a problem which again is an industry standard as the minimum for PC boards.