Any helpful hints for transfering toner to PCB?

Whelzorn

I swear to god I must have tried this 20 times in the last 2 days. I have used Staples Photo Paper, wax paper, magazine paper, label sheet paper, and just about everything else. What am I doing wrong??? I print the design on the paper, place it on the cleaned/sandpapered board (although I've tried it without) and press the iron on it and press for 30 seconds. I then try and move it around a bit, but even if it doesn't slip and smudge the design (which happens with everything except the photo paper) it doesn't transfer all the way, and I end up with half the board non transferred at all, and the other half so well transferred that it takes a miracle to clean it off to try again. Seriously this is driving me crazy.
And then the fact that this is a DIP propeller board means that I'll have to drill upwards of 120 holes total. So I need a reliable, repeatable process for doing this that will let me try again in case I screw up somewhere in the loooong process. I would love to just order the damn boards, but I can't afford to make a mistake in the layout if I do at like $20 for a small board. Or I could wait 3+ weeks to have it done through batchPCB or something.
Do you people seriously have any success with this? I can't fathom how anyone gets predictable results.
Oh, and to top it all off my boards are double sided. Fantastic.
Thanks,
A frustrated noob

Forrest

Its sounds like you just need to leave the iron on longer. I've had good luck with the Staples Photo Paper - but it took 3 tries to get it right. Hold the iron firmly on the board for 15 seconds, move the iron slightly, iron for 15 seconds, etc. Total iron time was about 1 minute.

Normally I wouldn't use sandpaper to clean the board - the copper is only .0014 inch thick. Steel wool and nail polish remover and 15-30 minutes of scrubbing should get the image off the board.

RDL2004

I agree with longer - 1 to 2 minutes seems about right.

Also file down the top edges of the board in case there are burrs where the copper is bent up slightly from the cutting process. These can prevent the iron from making full contact, especially near the edges.

I clean with 400 or 600 grit wet sanding followed by an abrasive cleanser like Ajax or Comet, then water rinse. If you don't get ridiculously aggressive, you will lose very little copper from the sanding. Scotchbrite type pads instead of sandpaper also work well.

After transfer use a solvent like lacquer thinner, MEK or acetone to remove the toner. If you use nail polish remover, be sure to wash the board afterwards since they contain oils and moisturizers in addition to the solvent, which can leave residue that impairs solderability (you should always clean the board before soldering anyway).

Personally, unless it's a very simple board that is needed "right now", I would go with a commercial supplier.

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- Rick

Bean

I have used this special paper http://www.pulsarprofx.com/PCB/a_Pages/4_Products/4a_Transfer_Paper/Transfer_paper.html

It's expensive, but it's the best I've ever used. After you laminate it to the PCB, you put the board (and paper) in the sink filled with water and the paper literally floats off the board. There is absolutely NO toner left on the paper. I have done 0.010" lines with 0.010" spacing with no problems.

Bean.

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LoopyByteloose

It might be better to clean the copper with DuPont Polishing compound [noparse][[/noparse]much smoother than 220 grit sandpaper or steel wool]. Polishing compound is sold at auto supply houses to remove scratches and rough spots from auto paint finished. There is also, Rubbing compound which is a bit courser. Both are handy and can remove deep scratches in Lexan or plexiglass. You can even clean up a damaged CD to get one last download from it.

Then wash the residue off the copper with mineral spirits, laquer thinner, acetone, or - if nothing else - rubbing alcohol. The rubbing alcohol is a bit corrosive, but it and acetone are least harmful to one's health and liver function.

All that might get the toner to attach more evenly.

Pulsar is a whole system and relies on good outcome to keep its customers. All the DIY tricks are cheaper, but more varied in result. I personally prefer photo emulsion and printing a transparency on an HPInkJet [noparse][[/noparse]the only one with the right ink for dense black transparencies].

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pwillard

I agree with a lot of what has been said. You almost want to polish the surface versus scratch it clean so use steel wool or really fine grit paper (The kind you need to use with water) and then clean with something like alchohol or acetone and don't touch it. I always leave the iron on the suface for a while (like a minute or more) and use light pressure. I went longer than 30 seconds in my case because I'm using a little travel iron i picked up from a yard sale so I felt I was making a more personal adjustment... but I guess it applies to more than me.

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There's nothing like a new idea and a warm soldering iron.

Harrison.

What kind of laser printer are you using? Some types don't apply as much toner to paper as others. HP lasers generally use a lot of toner, which is good for making PCBs. I personally use a Brother B/W laser and it works great for making PCBs using magazine paper / staples photo paper.

Also, make sure you are using a black laser. I have a color laser at home and it does not work since color lasers seem to use a higher temperature toner. I believe they also use a different kind of plastic since it looks different when printed on paper.

Harrison

Whelzorn

I use an HP Color LaserJet 1600, and I can feel the raised traces from the toner, so I think it's plenty.
Maybe I should just try the photo emulsion method, since it seems more repeatable and it's not much more expensive for coated boards.
Either that, or I'll try the pulsar system. Has anyone had any experience using a laminator to apply the necessary heat/pressure to the board? What about the "Toner Applicator" that pulsar sells?

Thanks again

Harrison.

Try a black and white laser printer. I believe all color lasers use higher temperature toner which makes it harder to work with. Color lasers also seem to use less toner then other ones, probably to allow the toner to mix better (someone correct me if I'm wrong).

I remember I tried to create a pcb using the toner transfer method using my color laser at home (it's a xerox/dell color laser) and I was not able to get anything to transfer. I even sent the photo paper through 4 times to get more toner on the paper. I gave up and just went back to my b/w laser.

Harrison

Post Edited (Harrison.) : 9/30/2007 3:38:01 AM GMT

deno

Two things might help you...I use a 3M Green scrubbie to clean my boards.· No chemicals.· I then run water over the board to see if the water beads anywhere.· If it does, I scrub it again.· Then I dry it.

Second...I find that a single sheet of regular paper towel between the iron and the transfer works to give you more even heat to the transfer, and also provides a coushion so the iron does not melt or scorch the transfer.· You will notice that the iron will "slid" easier over the paper towel as it heats up the transfer itself.

Deno

Twisted Pair

A clean Board, proper heat, applied pressure and the heat time will all make a difference. (1) Clean your board with a green scotchbrite pad and dishwashing liquid, Scrub in both directions ( up & down and across), then rinse well with water. Don't touch the board with your fingers while cleaning and up until the toner is applied. (2) Set your iron to approximately 300 degree's. (3) Align your toner outline paper over the board and then lay a regular sheet of paper over that. (4) With the iron hot, press down hard on the transfer for approximately 3 minutes. Note: If your board is larger than your iron, lift and move the iron to heat all areas evenly during the 3 minute heating time. (5) Once the heating time has elapsed, remove the iron and the regular sheet of paper, quench the board and transfer paper in a bowl of cold water being careful to lift everything up by the the edges/bottom of the board and not the transfer paper. This will help prevent pre-peeling of the toner from the copper clad until it has cooled in the water for about 30 seconds. (6) Once the board has cooled in the water, slightly peel back one corner of the transfer paper to inspect the toner for good adhesion. If the toner is not solid, re-heat for about a minute and then re-cool in the water. Hope this helps....

Twisted Pair....

SailerMan

I found that my Iron wasn't evenly heating the board so I took a piece of 1/4 aluminum and placed that between the Iron and the board... Yeah it too a little longer to heat up the Aluminum but It gave me a more even heat... But all in all I find the Photo Etch method better for me.. I created a mini Dark Room which really isn't necessary ... If you don't mind using another chemical this method is nice because you can keep reusing the transparency. It takes a few minutes to create a board ready for etching. I have never had a bad board or wasted materials this way (Unless my board design was wrong).

If I could have back all of the time I wasted on toner transfer... [noparse]:)[/noparse]

Eric