Press-n-Peel PCB problem


Mr. RB,

Where have you been? I thought that everyone here knew by now that I use P-n-P and have a lifetime supply! It is excellent stuff that I have been bragging about for years!
But why some people insist that they have to use a laminator is beyond me.
I am just playing around with this DIY toner paper.
 
Rolf said:
But why some people insist that they have to use a laminator is beyond me.
Click to expand...

WAY more uniform pressure and temperature, stability of the sheet - there are some physics involved that make heated rollers very superior to scrubbing around with a hand iron.
 
duffy said:
WAY more uniform pressure and temperature, stability of the sheet - there are some physics involved that make heated rollers very superior to scrubbing around with a hand iron.
Click to expand...

Your statement makes little sense because:
1. "WAY more uniform pressure and temperature"
The heated roller only makes contact with a small fraction of the surface at one time so only that small part of the board has the proper temperature and pressure at any one time! That is not uniform by any standard. Proof of that is that the board more than likely has to go through several times.
If you want uniform heat and pressure and not use an iron then you have to resort to what is called a T-shirt decal transfer press.

2. "there are some physics involved that make heated rollers very superior" Please explain.

3. "scrubbing around with a hand iron" If you do that you are probably better off with a laminator. My P-n-P instructions doesn't mention that particular technique at all.

I guess the proof is in the pudding, whatever works for you is ok.
 
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I use a hand iron. I keep thinking about spending the money on a laminator, but the iron just always works. Never had any problems with it. My Wife gets a little annoyed with the flat board that I keep beside the ironing stand, though.
 

Sorry Rolf, I didn't read all 159 posts before I started shooting by big mouth off.

But the laminator is a given. I tried a few pressnpeel tests with an iron, and I'm not stupid or clumsy. Results were pretty poor, even with using my infrared non contact themometer to try to replicate the right iron or PCB temperature. Shrinkage, smudging, creep, blurry lines, undercooked patches you name it every test I did had a problem or number of problems.

Then after seeing people use laminators on this forum I got a crappy little $25 USD laminator and suddenly perfect results with razor sharp lines even at 0.010", even the PCB dimensions outline at about 0.005" would have made a working track. Just the laminator was a touch underpowered so I opened it up and fiddled with the temp control trimpot to make it perfect.

If you ask me they should just supply a kit and be done with it; laminator and pressnpeel together.
 

I have been trying to figure out why some can't get the iron to work. You definitely tried by setting the temperature with a IR thermometer.
I have to admit that my good results have all been with boards four square inches or less (newer needed anything larger). so what size boards were you trying to make before you got your laminator?
I and many other that have success with the iron method use a clean sheet of copy paper over the P-n-P, seems to decrease drag and the chance of the transfer slipping and cause smudged lines. A cushion of newspaper underneath also helps.
On the subject of under cooking, burnishing the edges of the PCB is a must. Also check the flatness of your PCB and the iron, if either one is curved you have to adjust your ironing technique accordingly.
 
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Warning!

Mr RB said:
{snip} Results were pretty poor, even with using my infrared non contact themometer to try to replicate the right iron or PCB temperature. {snip}
Click to expand...

Checked the temprature of my iron with a calibrated digital thermocouple meter, it howered around 283°F. (I thought I had set it for 300°F, so it drifted a little)
But when checked with my infrared non contact themometer the iron only read around 130°F! Granted I don't know what the upper limit is on these these type of meters.
So that might be part of your problem.
 
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It's not the upper temp limit its caused by the type of thermometer, IR therms can't get a good reading from shiny metal surfaces. Try sticking a white sticker (label) on the iron and test it then.

Mine is a real old iron and has the alloy anodising all burnished and matte on the bottom so I could get a pretty good reading. Temps tried from 120'C to 150'C, and i measured on the white paper on top of the film immediately after removing the iron. I was using small PCBs 2x3 inches etc. Part of my problem was technique with the iron, even with the bit of paper over the pnp with small PCB it was impossible to hold it, and moving the iron caused some smudging. Likewise over pressure caused some bleed, and trying to leave the rion stationary caused other problems because the iron surface was not at even temps, it was hotter in one place in the centre where I assume the element was riveted to the plate so that caused uneven cooking and the steam holes were tapered and these left cold spots unless I moved the iron.

Basically because the iron heats the entire film, the toner "wets" and the whole film can very easily move and smudge as you move the iron. I was also getting a measured shrinkage of 1% or so which is quite bad, and i assumed was due to overcooking, but running the iron cooler caused missed spots each time.

My theory on the laminator is that after the first pass the film stuck hard to the PCB, and was only "wet" in one place at any time (where it touches the hot rollers) while the rest of the film is much cooler and there was no shrinkage because the average heat x time is very low. Also the average PCB temp is MUCH lower, so the PCB is not expanding/contracting like a fully hot PCB under the iron which does a large expansion etc while the toner is wet.

Likewise there was no smudging or movement as the film is stuck to the PCB and all times and only one small line gets "wetted" at any one time.

Then add in the exact same heat on every part of the PCB and exact same temp on every part, with no exceptions, and the added bonus of much easier inspection after each pass in the laminator etc etc and just counting the number times means less error and stress.

That think that might cover some of the "physics" that duffy mentioned above.

I'm not saying anything bad about pressnpeel really, probably the opposite; with the laminator I think it gets close to the quality of home photographic etching but so much faster and easier.

And the last 2 boards I just left the pnp on the copper, and scratched off just the pads with a little screwdriver before I soldered. So it's a solder mask too although it's not pretty that way.
 
PCB Ironing Setup.........


"Basically because the iron heats the entire film, the toner "wets" and the whole film can very easily move and smudge as you move the iron. I was also getting a measured shrinkage of 1% or so which is quite bad, and i assumed was due to overcooking, but running the iron cooler caused missed spots each time."

My ironing setup consists of a clipboard (masonite) with a section of newspaper folded up for heat retention and a clean sheet of copy paper on top. The PCB and the transfer paper goes underneath the copy paper.
Since the everything is held in place by the clip on the board there there is little change of anything slipping.
Too further reduce the chance I jut put the iron on top for about a minute then i rotate it 90° and let it sit for another minute, then I do a little "ironing" for a minute or so.
Never had any problems with P-n-P or magazine paper transfers due to my primitive setup.

You should be able to adjust the iron temperature by setting it on an owen thermometer, some insulating material must be put underneath. I am talking about the type that has the probe extended out from the scale. Shoot for 300°F. (149°C)
 
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Toner transfer to alluminium

I bought a HP-P1102 laser printer and some Staples "photo basic" gloss paper.
I read this was a good printer and paper for toner transfer.

For my project I need to toner transfer to alluminium that I than can work on without the need to draw lines on the alluminium wich are not accurate enough.

I first tried with an old iron, but that was not good enough, to hot, no temp control.
I bought a siemens iron, good temp control, and worked better.

I tested it around 20 times, but I still not getting verry good results.
I can get an 90% coverage when I iron for 10min with force. But never perfect.
Most of the toner also get covered with the glossy layer of the paper wich makes the toner turn light blue, and harder to see than the black.

The alluminium is to thick for a laminator I think.
Most of the components are 2,5mm thick. Some even 8mm.
All laminators I see only can go up to 0,6mm thick.

The results just do not have a perfect coverage, but they are accurate, no smuged results (except when I use the back side of the paper, than I have nog glossy layer, but it's not accurate).

Also, the paper always gets off easily, not need to keep in water for minutes, that doesn't do a thing, maybe it's the paper, but it's good I gues..?
anyone knows for example how to remove the light blue glossy layer after toner transfer, that would me it at least better.

Anyone experience with toner transfer to alluminium?
 
I have never used photo paper so i can not help there.

What i have used with excellent results, is the waxy, shiney paper backing that stickers come stuck onto.

If you buy a pack of laser printer labels and pull the labels off and use the backing paper to print onto the shiney side you will get good results.

There is no need to wet it to remove the paper just allow it to cool after ironing and the paper will just peel away clean.
 
How do you clean the aluminum before the transfer, I know when I did PCB's the copper had to be squeaky clean (shiny).
Are the edges deburred? This is very important step otherwise you will not get good coverage all the way to the edge.
How large are your aluminum plates? I am sure they soak up a lot of heat so you need a thermo barrier (insulation) underneath. I used newspaper.
If your sheet is not much bigger than the iron then just let the iron sit and preheat, you have to experiment to find the correct length of time, you should only have to iron for the last minute or so, I newer had to use a lot of preasure. And it makes no sense to iron if the temperature is not high enough.
 
The Staples paper doesn't work anymore. They changed that paper a while ago and it's useless now. I still have a batch of the old stuff I use. I don't know what the current favorite paper is, but you can try the heavy gloss magazine paper that people suggest here.
 
I tried magazine paper ones, that did not gave a good result.
This paper absorbed to much toner I think.
I will try different magazine papers soon, maybe there is one thats perfect.
But what's good about the Staples paper I now have, it does not smudge. The glossy layer seems to project against that.
The back of that paper works, but smudge fast.
I think the back of lable paper wil smudge fast also, does it?

I cleaned the small alluminium plate with different things, thinner, water, soap and some kind of spray. It does not seem to make much of a difference.
The spray worked nice, some kind of acetone, does not smell like thinner stuff.

To show my latest result (staples paper), 10min ironing...

**broken link removed**

It did not smudge, but the coverage is not perfect.
At this picture the glossy layer on top of the toner is clearly visable.
But at some angles, the glossy almost looks black.

I tried some surfaces to iron on, metal surface, paper and wood. One time, I could not get any good results anymore, the wood was the problem, after all that presure, to wood was not flat anymore.
The alluminium also have a little high edge, thats something I can work on next.

My iron also is a steam model. Because of the high wattage of 2600 watt. There was only one non-steam model, 1000 watt.
Because of the holes in the steam model, I change angles every 30-60 sec.

This alluminium is 55x66mm. I'am going to do 250x80mm to, I hope I can get a acceptable result with that to. But I hope to improve it.

As you can see I use allot of outlines to try to get the image correctly on the alluminium, but thats not going perfect. there is still an angle.
I can't use tape to hold the picture I think, or can I?
 
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for $147 I will use EXPRESS PCB for FREE
Auto route is nice but I think most people end up routing themselves.
 
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