We are doing cold foil on our press with the following:
Aniloxes tried: 250 LPI, 360 LPI, 400 LPI, Apex GTT L, Apex GTT M, Apex GTT XL
Foil: OP foil from Kurz
Adhesive: Foilbond from Flint
Plate thickness: 1.14mm (Cyrel Fast)
Tape: Tesa 52015 Medium Hard 0.381mm
Substrates tried: Mirror Coat 80 GSM, Self adhesive stock with face of mirror coat, Self adhesive stock with face of chromo paper
We have changed aniloxes, plates, different lots of foil, different lots of adhesive but still the problem of pin-holing in the foil does not end. The shore hardness of the nipping roller for foil is currently 70 -75 shore. Kurz suggests 80-85. Some other opinions are that we should try 30-35 or 40-45 shore nip rollers. Will this help?
Changed the foil unwind and rewind tension to high and low. Changed the nip pressures (since it is pneumatically operated nip roll for foil). Changed the UV power levels (GEW), changed foil unwind and rewind path. Made sure that there are absolutely no wrinkles at the point of nipping and no air trapped until it goes through the UV. Once it passes through the UV and goes to the roller beneath that, the foil is separated and we see some air trap at this roller where the paper and foil separate. Could this cause problems?
Examined the foil against sun and can see some pinholes in the foil itself (but far lesser than what we see when it is transferred to paper) and hence come to the conclusion that maybe the foil is ok. Ordered some more foil to see if we can get better foil and can reduce this problem.
Really tried everything we could but something is missing.
Worst part is that when we tried the foil at previous occasions with same variables, no pinhole problems were seen. Only change is that now the design is more solid (like a band of 12mm going around the label - it is a liquor label)
H E L P !!!!!
I am at my wit's end!