PCB Toner Transfer Issue

Thread Starter

NikoTek

Joined Sep 8, 2020
4
I am trying to fabricate a double-sided PCB circuit using the toner transfer method. I use a steam iron to transfer the toner from transfer paper to copper. Once one side is transferred I drill a few holes for alignment and pass some needles and then place the second side of the circuit print and transfer that.

The issue that I am facing is that once I start transferring the second side of the circuit onto copper, the toner that was already transferred to the first side starts leaving the board and starts getting transferred to the surface on which the first side is placed. I have tried different surfaces like cloth or wood. But in both cases the first side transferred toner starts leaving the copper.

Looking for suggestions to help avoid the issue may be some sort of paper or tape that might not attract the toner from copper which I could place beneath the first transferred side.
 

jpanhalt

Joined Jan 18, 2008
10,219
Might try non-stick aluminum foil (Reynolds) or plate glass. I would spray the latter with a silicone oil, then wipe it as dry as possible.

1600257352271.png

Do you leave the toner carrier (paper?) in place on the first side?
 

djsfantasi

Joined Apr 11, 2010
6,792
Why don’t you etch the first side while protecting the second side?

Cover with self-adhesive vinyl, paint or permanent marker. After etching, remove the protective coating, and transfer the traces to the second side as before. Protect the first side and etch.
 

Thread Starter

NikoTek

Joined Sep 8, 2020
4
Might try non-stick aluminum foil (Reynolds) or plate glass. I would spray the latter with a silicone oil, then wipe it as dry as possible.

View attachment 217361

Do you leave the toner carrier (paper?) in place on the first side?
Thanks for the suggestions. No, I don't leave the toner carrier paper in place. As I transfer the toner on the first side wash it with water remove the paper if the transfer is good, drill a few holes and then align and place the second side with no paper on the first side.
 

Thread Starter

NikoTek

Joined Sep 8, 2020
4
Why don’t you etch the first side while protecting the second side?

Cover with self-adhesive vinyl, paint or permanent marker. After etching, remove the protective coating, and transfer the traces to the second side as before. Protect the first side and etch.
You are right that could be done. Just want to save time and some extra steps as if both sides are transferred etching can be done in one go.
 

AlbertHall

Joined Jun 4, 2014
10,388
The first transferred side will be vulnerable to damage mechanically even without heat.
I think you will need to etch the first side before transferring the second side.
 

peterdeco

Joined Oct 8, 2019
220
I make single sided boards with no problem. When I tried double sided I had the same problem. So I made a board for the top layer and another for the bottom, glued them together and used resistor or diode leads to join the vias. The systems works, but since then whenever I need double sided, I send out for them, choose 1 day turnaround and have them overnighted to me. It's expensive but saves a lot of time and work. And besides...the company pays for it.
 

ChetanShah

Joined Sep 19, 2020
5
Here are a few things that you can try.
  1. Try a different glossy paper. Don't bother with magazine and newspapers they don't work very well.
  2. Check and remove if you have set a "toner saver" option in your printer.
  3. Set the "maximum density" in printer settings.
  4. See if the print on the paper is dense. And doesn't look faded.
  5. Try a different printer if above three options don't work.
  6. Make sure you've set maximum temperature in your iron. Or try a different iron if you think that can be a problem.
  7. Apply uniform pressure to the board. DON'T slide the iron over. It has a slight risk to "smudge" the print.
  8. Judging by the looks of your print. It's either the toner lacking in the print or proper heat is not applied to the board.
  9. Print quality should look something like this.
PCB.png
 
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