TV, Radio, VCR, CD player, cassette deck - almost all use single-sided boards. Double-sided are becoming more common now, mostly as the result of SM components.Originally Posted by justDIY
A double-sided board costs a lot more than single sided, in a mass production item using single-sided makes a worthwhile difference to the price.
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk
You must be doing somthing wrong. My results are as good as they need too be.
Currently I am drilling my holes with a CNC then etching one side while the other is covered with box tape. It takes about 10 minutes to etch a side depending on the copper thickness.
I have been doing DIY PCBs off and on since we laid them out using chart pack tape. It has never been this easy.
I have made numerous DS board via toner transfer. You just have to pay some care to getting proper alignment. Once you can do that, it's pretty easy. I make every boad DS these days.
One simplification is to make a DS board but use one side as a ground plane. That really simplifies your layout AND makes for a much quieter design as well. A tip - use thermals on the ground pads. It's a real PITA solder with out them.
I took another look at the Pulsar web site to see where they had run 3 lines between pads and found they had only done two. Brain fart.
The above pic is a good example of what you can do with the paper. It is typical of the results I get, I do not use the green lacquer.
You can see that with 1 you are not pushing the process. I have only done 2 once.
You have to use the right transfer paper instead of stuff you find at Staples or a page from magazine.
Alignment aint the issue, neither is getting a decent layout... The PnP blue film seems to be extremely prone to leaving pits or missing areas on tracks. I clean the boards with wire wool, followed by a pcb cleaner block, and finally a good ole degrease with IPA and acetone (pure, not nail polish remover!!) mixed 50:50....
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Shax.
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A bus station is where a bus stops...
A train station is where a train stops...
On my desk I have a work station...
Nuff Sed!!!
Those 5mil lines on the 20mil grid don't look very good to me.
I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.
Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.
Maybe Evan can help you with that, he has more experience with PnP.
Your problem may be with the toner cartridge itself. For best results buy a new one and use it only for PCBs till your other one goes dry. For best results use a laminator instead of an iron.
With the Pulsar system you apply one or two layers of green TRF (toner reactive foil) to the toner prior to etching. This extra step helps prevent the type of problems you are having. It is easy to spot toner with no foil or spots with no toner. These can be hit with a sharpie and a second layer of TRF applied. With a reasonable toner cartridge fixups are the exception. Most boards do not need it.
I can assure you that alignment, most certainly, IS an issue. Getting the top and bottom artwork so they are within 5 mils or so is important. It's not hard but still pretty important.
cleaning with steel wool - that could well be your problem. Everything I've read says not to use steel wool. I use wet-or-dry 600 grit paper and acetone to degrease. Never had a problem.
Steel wool usually contains anti-corrosive treatment, which might be oily.
On the other hand, "SOS" pads contain a good degreasing soap and I've had good results. Rinse throughly.
Has anyone tried quickly dipping the bare board into etchant to verify it's really clean? Then rinse, dry and transfer the toner...
I am still surprised that people have this experience, I really don't know what the secret is. Seriously, I put very little effort in when I make my boards. I scour with scotch-brite until the board is uniformly clean, then wipe with isopropyl on a paper towel, and iron away. I'm NOT very careful and consistent while ironing, and yet my boards always come out great. I pretty much never get any pitting or broken traces, even though I'm using a cheap no-brand refilled toner cartridge in my printer that does tend to leave small pinholes on the printout. I've even used various iron temperatures and never noticed tremendous differences.
I guess I'd still just recommend trying the dowel method and playing with your iron temperature just to be on the safe side, even though I didn't have troubles even when I was just ironing on a flat surface. Once again, there's a tutorial on my website detailing the method that I use, if you run out of ideas perhaps you can try to duplicate it and see if it works out any better.
The only other variable I can think of is what 3v0 mentioned, and it's an important one: toner. The toner is what has to stick to the board and so the toner in use makes a tremendous difference in how good your adhesion is. If your toner really doesn't want to adhere to the board, it's not going to matter what transfer film/paper you use. If you're getting a lot of lifted traces and pits, perhaps you should try a higher iron temp to make sure your toner is melting completely. Unfortunately, of course, toner is the most expensive and difficult thing to "experiment" with because toner cartridges aren't cheap and you usually don't have many choices about brand or quality.
Last edited by evandude; 23rd March 2007 at 12:16 AM.
I use Dawn and a green scotchbrite pad.
It is not hard to get the board clean, not touching the surface once clean is. At times I have used nitrile gloves. Maybe overkill if you wash you hands well to start with.
Be sure you are not blaming the cleaning process when the problem is elsewhere.
I am a big fan of using a laminator. It takes most of the guesswork out of the process and is repeatable.
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