Originally Posted by mvs sarma

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.

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.

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.

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.

Originally Posted by DirtyLude

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.

Originally Posted by Angelgroove

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.