Improved PCB Manufacture

By | 15th July 2017

Having had some inspiration from another Radio HAM, G0SLV, on an improved toner transfer method I invested in a new heat press to make the toner transfer process more successful than previous attempts using a normal household iron.

The iron method was always hit and miss – sometimes I got lucky, other times not so and this became a very frustrating process when it did not work after so much time put in to the job. The heat press is a standard T-Shirt press also know in the industry as a “Sublimation machine” which applies a high temperature (190 degrees centigrade in my case) with a large amount of even pressure for a given length of time (62 seconds worked for me).

Dave also brought “TRF Foil” to my attention and this serves as a coating for the toner to eliminate any porous areas which can lead to pitting of the copper during etching, so here are my first two boards made using the new process and what a dramatic improvement over previous methods used – note that the larger board was coated in TRF Foil and the smaller daughter board was not, I did not notice any pitting of the undercoated board which was quite a surprise.

  1. First Mixer board – after toner transfer and with Green TRF Foil applied.

First Mixer PCB after toner transfer

After etching process – I need to dress the edges of the boards where I trimmed them with my saw.

I must also note that I moved away from the normal glossy photo paper as this left a great deal of paper residue after transferring the toner and washing the board, it was again hit and miss if you got a good etch as almost every time you would end up with a fine layer of paper masking some copper and it would not etch – besides the method of removing said paper residue was quite rough and would lead to loss of toner image from the copper at times.

The new paper I used was much thinner and of a mustard colour, I bought this from Ebay for a few pounds and after the heat transfer process the paper just peeled away leaving no residue and I did not lose a single pixel of toner – very pleased with the result and it saved so much time too.

Here is a link to the paper I used: Toner Transfer Paper

Here is a picture of the heat press, it was an investment that will guarantee quality boards every time and based on the old method which consumed more time and material I am sure I will recover my £84 investment quite quickly.

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