Electronics Forum | Wed Sep 08 05:17:04 EDT 2010 | eddtsk
Hi, ran across a batch of PCB that has white silkscreen during receiving but turns purple/pink after our reflow process. SEM/EDX test can show there is no significant different element between the white and purple silkscreen. Can any help advice what
Electronics Forum | Thu Sep 09 13:25:22 EDT 2010 | eezday
I've seen the purple silkscreen before on ENIG board built with PbSn process. I would think that if temp is the issue the lower process temp would not have caused the purple ink. I remember that the flux I used was water soluble and I attributed th
Electronics Forum | Wed Sep 08 20:14:27 EDT 2010 | eddtsk
Hi Davef, ues, its ENIG. But do you know what the causes this? We send the board for testing but finds nothing defferent chemically between the white and the purple silkscreen. The supplier claim that its our process that is caused the changes.
Electronics Forum | Wed May 30 10:09:39 EDT 2012 | brettrenishaw
Recently we have noticed a purple-blue colour film on the surface of the molten solder. It can be cleared when de-drossing the pot. The pot will normally go a yellow/gold colour before it turns purple-blue. Is this most likely an oxide of the tin or
Electronics Forum | Sun Mar 12 18:20:08 EST 2006 | jldowsey
Thanks Russ. As it turned out, it was an incomplete cure at the fab house. Rhey sent another fab over from the same lot that had sat for 3 more days, and it came out lavender instead of purple! have a good one!
Electronics Forum | Wed Sep 08 15:21:31 EDT 2010 | davef
ENIG boards, correct? If so, you'll find that purplmation of your silkscreen has nothing to do with your process and everything to do with the quality of your in-bound boards.
Electronics Forum | Wed Sep 08 21:17:05 EDT 2010 | davef
Technical data sheets from the ink supplier will: * Describe testing has been done * Recommend to their customers the limits of exposure to thermal, chemical, and mechanical conditions.
Electronics Forum | Wed Sep 15 23:48:43 EDT 2010 | mily
We drilled a hole in the centre of the LGA and put the thermocouple inside, so we measure the exact temperature between PCB and device. http://www.jewellerybeadsale.com/
Electronics Forum | Fri Sep 17 11:55:31 EDT 2010 | qualityguy
All, Get the material data sheets, lot numbers of ink, supplier's process flow, bare boards with ink lot applied ( qty 20), Contact the ink supplier and perform a 3company DOE.
Electronics Forum | Thu Sep 16 00:23:43 EDT 2010 | eddtsk
Hi All, thanks for your precious reply. We had been trying very hard to ocnvince the customer that there is nothing wrong with the PCB but they are still unwilling to accept the change of silkscreen color. We attribute the silkscreen issue to a bad b
winsouce.jpg)