Pink PCBs..!

[mikeselectricstuff]

Had an interesting problem today - some ENIG (gold finish) PCBs with white resist turned a pale pink when they went through the oven.
Apparently something in the ENIG cleaning process affected the ink chemistry (the assembly subcontractor had seen this before).
Fortunately I realised that we could just get the resist re-printed & this saved the day with only a day lost. 

[SeanB]

Do it as a feature..........

[mrflibble]

Do it as a feature..........

What he said. Add a flower motif to the silkscreen, slap an ar-suckmy-duino on it somewhere and hawk your wares on kickstarter. Bound to sell!

[Bored@Work]

Time to connect to your inner feminine side.

[Smokey]

before and after pictures?

[mikeselectricstuff]

before and after pictures?

[nicknails]

We use white resist on all of our boards and I've seen this happen a few times.  Not to that extent, more of just a pinkish hue.  We've never really seen it as a problem and all of our parts are encapsulated.

[deephaven]

Why not introduce a line of electronic Barbie Dolls? You could call them Barbduinos 

[kc0ngu]

Does it only happen over ENIG?
If it happens with regular HASL, it might not be the ENIG, it might be migration of a blue, violet or similar pigment/dye in the resist. White inks sometimes use these added colors to increase the apparent 'whiteness' of the white ink, especially if a cheap or low quality white pigment is being used. Most times these added colors dont show, but reflow and solder temps can play rough with (poorly) formulated inks/resists.
Not a real answer I know, just my 2cents from 30+ years of designing these coatings and (trying to) solve similar issues on the PCB shop floor.

[mikeselectricstuff]

The PCBs were re-printed with the same resist ink, and came out fine, so pretty sure it was something that happenned during plating.

The PCBs were for this BTW...http://www.uva.co.uk/work/continuum

[EEVblog]

Had an interesting problem today - some ENIG (gold finish) PCBs with white resist turned a pale pink when they went through the oven.
Apparently something in the ENIG cleaning process affected the ink chemistry (the assembly subcontractor had seen this before).

Yes, I've seen this before quite a few times, not uncommon. Although I thought it was pretty much history these days.

[jmole]

The PCBs were re-printed with the same resist ink, and came out fine, so pretty sure it was something that happenned during plating.

The PCBs were for this BTW...http://www.uva.co.uk/work/continuum

beautiful piece. how'd you end up working with these folks?

[kc0ngu]

The PCBs were re-printed with the same resist ink, and came out fine, so pretty sure it was something that happenned during plating.

The PCBs were for this BTW...http://www.uva.co.uk/work/continuum

OK, thanks for the update Mike, I will have to have a think about what else might be in going on, appreciate your work (and videos
's) as always, impressive end result/installation.

[Corporate666]

Can you disclose who the PCB manufacturer was?

I just got a very expensive quantity of white soldermasked boards with ENIG plating.... haven't used any yet but maybe I should run one through the reflow process to see if it turns pink!