Hi !


I have tried the toner transfer method for several boards. I had
to experiment many times until i got acceptable results. It depends on
many parameters.

Some hints from my experience:

- The Board:
After cleaning the board from oil and dirt pre etch it by putting it
in the etchant (FeCl3) for 0,5 to 3 seconds (depends on temperature and
etchant quality) and immediately wash it with clear water. The toner
sticks much better to such a surface.

- The Paper:
I have tried different papers and foils, including a special foil called
'TEC2000' for toner transfer.
The best results i got were with Hewlett Packard 'non-glossy plotter
paper'. I suppose for good results the paper have to be with a glossy
surface where the hot toner stays on the surface and doesn't suck deep
into the paper.
Could never try the products mentioned on the list since i couldn't find
them here in Germany.

- The Toner:
I noticed newer 600 dpi laser printers use fine grained toner and bring
less toner on the paper. Older 300 dpi printer worked better for me.

- The transfer method:
The result depends highly on temperature, pressure and duration of the
transfer process.

I am using an Iron hold upside down in a vice. Then put the board on it
with the cooper side upward and press the printed paper with a rubber
roller.

I want to replace the iron by a hot plate with a temperature
controller (PIC-based with PID algorithm :-)

It is important always to apply the heat on the one side and transfer
the toner on the other side.

- The Results:
I have done a double side 100 x 160 mm board.
The board is usable but i can't say it's perfect.

The result is acceptable until it's cheap. If I would be going to spent
money for PCB equipment i would bye an UV exposure unit and use
ready made pre-coatet boards.



St.