Electronics Forum | Thu Feb 07 14:58:08 EST 2008 | operator
We don't have one of those cool air compressed syringes to dispense adhesive. We have to do it by hand. My question is does anyone have any suggestions on syringe size, needle size etc... for successful deposition of SMT adhesive? I know you can go s
Electronics Forum | Tue Feb 12 17:57:42 EST 2008 | chef
I must ask the silly question- are you sure you deposited the correct amount of paste? Depending on aperature design-the voiding could come from a stencil that has its holes partially built up with old paste. If paste volume is guaranteed, then what
Electronics Forum | Fri Mar 14 15:14:31 EDT 2008 | samir
Dean, thanks for schooling me on this. I talked to an industry collegue whom I met at APEX, and it was he who had told me of the IAg "rework issue." Basically, he told me that they had field failures on QFPs that were a direct result of trying to "
Electronics Forum | Fri Mar 14 11:25:02 EDT 2008 | hegemon
ol' hege has got to agree with Chunks and Dave. Seems every time there is a problem, the finger is first pointed at the process. For my $.02 it doesn't matter if your process is 100% bulletproof, procurement will screw it up by finding a vendor that
Electronics Forum | Mon Mar 24 09:09:40 EDT 2008 | jdumont
Hello all, we have been seeing a lot of issues with broken or open vias on a couple of our bare boards. We have two vendors make these for us and the issue is only with one vendors boards. We have stopped using them until we can figure out what is go
Electronics Forum | Mon Apr 14 16:21:58 EDT 2008 | ck_the_flip
Bottom-side SMT parts CAN and DO go liquidus during the 2nd reflow cycle. It could be that there was enough variability between the 2 different lot code PCBs to cause the parts to fall off. Remember wetting force determines surface tension (the abi
Electronics Forum | Tue Apr 15 21:24:41 EDT 2008 | davef
We find it curious that: * Heat slug pad for Q19 didn't take solder, indicating a pad [board] solderability issue. * Signal termination pads for Q19 didn't flow well, indicating a poor thermal recipe or a pad [board] solderability issue. * Signal ter
Electronics Forum | Mon Apr 21 11:55:29 EDT 2008 | realchunks
"Disturbed" usually means some form of movement. I would think your leads are moving due to warp as the board exits the reflow zone. Not knowing your profile, I would suggest checking your profile. Make sure you have adequate "above liquidous" and
Electronics Forum | Thu May 01 18:14:19 EDT 2008 | jmelson
Yup, this is pretty scary, all right. I have just used up the last FPGAs of a batch we bought from a Chinese source. Never again! Some of them worked, some didn't, in a variety of nefarious ways. People cautined me about empty packages, etc. Wel
Electronics Forum | Thu May 01 15:11:37 EDT 2008 | dphilbrick
CK So as I see it batch B represents a leaded process with leaded components and D is a leaded process with lead free components. Batch Components Paste B SnPb Sn62 D Lead-free Sn62 If so it is BETTER to run a lead free BGA with Sn
