Electronics Forum | Mon Aug 10 12:58:04 EDT 2020 | SMTA-64386637
We have found Acrylic CC under QFNs is a failure mechanism in thermal cycling. The coating acts as a wedge and causes solder joint cracks. We do not coat QFNs. To enhance reliability we have the vias plugged with solder mask. This eliminates some
Electronics Forum | Thu Apr 09 06:28:11 EDT 2009 | qualityguy
We have different Solder mask 'gloss' and 'satin' the gloss has a surface energy =40 dynes. The test evidence to date is strong correlation between surface energy, mask type, HASS failure
Electronics Forum | Fri Feb 26 10:42:56 EST 2010 | mleber
Your masking dots are a silicone adhesive. Contact the supplier and tell them you need an acrylic adhesive on the same dots. Normally same cost and lead time.
Electronics Forum | Fri Nov 04 16:36:53 EDT 2011 | davef
tombstonesmt: Ammonia based masks can create solderability issues after they are removed. You can get non-ammonia based latex mask material but down side is slower cure and cost a little more as they have higher levels of latex etc
Electronics Forum | Tue Nov 12 10:44:22 EST 2013 | aaronpavone
I have previously done a masking fixture through Pentagon, but was unsuccessful I think more due to the design of the board. Does anyone else have experience with other vendors that I could try out? I have seen InsulFAB and Ascentec as well. Thanks.
Electronics Forum | Wed Sep 30 18:48:56 EDT 1998 | Graham Naisbitt
Jim, Without knowing your location, I suggest: 1 Send me samples of the components you want to mask - maybe I have something available off the shelf. 2 Call Kinarney Rubber Company in New Jersey (sorry, Noo Joysy!) They have a wide range
Electronics Forum | Thu Feb 25 10:30:21 EST 2010 | davef
It sounds like your poly dots are secreting something that affects coating thickness. Is this a function of the adhesive used by poly dot supplier?
Electronics Forum | Tue Oct 31 19:34:30 EDT 2023 | dilogic
I have considered this solution, but syringe application is very slow and it's hard to control thickness. It's good for partial covering or applying peelable solder mask. We need to coat circular board ca. 10cm in diameter. Takes a while even with sp
Electronics Forum | Mon Aug 04 15:06:24 EDT 2003 | swagner
Don't forget to look into Nordson's coating equipment, it's more expensive than the other's but you get what you pay for.
Electronics Forum | Tue Jan 27 04:27:59 EST 2004 | loz
Thanks Dave, sounds totally plausible. In answer to Pete B's questions 1. Spot mask IS only being applied to earthing points, top and bottom side. 2. Unsure. Speaking to manufacturer they are telling me it is compatable. However data sheet is vague.
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