Electronics Forum | Sat Nov 10 21:15:04 EST 2007 | mika
make 4 square rounded corner apertures around the ground pad and the total reduction of 20 % (80 % solder paste). Then you still be able to solder the terminals around. We SMT-mount & reflow soldering various QFN packages onto our customers pcb:s wi
Electronics Forum | Mon Nov 12 09:22:41 EST 2007 | devajj
BTW, The surrounded QFN fine pitch terminals > should have the normal aperture reduction of 7 % > in case of RoHS Senju solder paste. This works > for our Telecom customer. > > The vias in the > ground pad will be somewhat filled with solder >
Electronics Forum | Mon Nov 19 09:34:50 EST 2007 | bbarton
Real Chunks...Yes, that's the most glaringly obvious defect in the short term (you'll probably find it on your production floor if it's really bad) but you may find that everything looks good short term only to have a high level of customer returns..
Electronics Forum | Mon Nov 19 19:14:07 EST 2007 | jmelson
I've been running 90% lead-free (still have a couple components I can't get reliably in RoHS compliance) with a peak temp of about 238 C, on standard FR-4 boards. The only real problem is the pad adherence is compromised, making rework of the boards
Electronics Forum | Tue Nov 27 19:41:53 EST 2007 | g2garyg2
Well, there seems to be many opinions, many of which could be correct, however... With the proper laser they can be quite good for soldering. Here are a few guidelines I would like to suggest. 1) Have your product soldered first (by the vendor) 2) T
Electronics Forum | Sat Jan 19 23:23:45 EST 2008 | bentigano
I'm not familiar with SPC Plus. I'll assume it's a "statical process control" system. We use the SPC data collected by our YesTech AOI system, together with a custom, web-based reporting system for process analysis and defect reporting. I am actually
Electronics Forum | Fri Dec 21 00:06:55 EST 2007 | nhantruong
If you want to use fuji CP6 machine, you have to buy the the fuji flexa software.Because the old software from fuji (MCS or F4G) they are not support anymore. In the flexa software you can make top and bottom side in the same program, you can move th
Electronics Forum | Wed Dec 19 20:42:55 EST 2007 | davef
gersla: You're correct that carriers of low temperature material will disfigure and become useless at 125*C bake temperatures. The reason you can not find 70*C bake data is: J-STD033B, "4.2.2 Low Temperature Carriers. SMD packages shipped in low tem
Electronics Forum | Tue Jun 17 12:57:26 EDT 2008 | sleech
You are correct. For the 70 deg. C drying temperature to be effective, the relative humidity must be as near to zero as possible. A pulling a vacuum on the chamber is an inexprensive and reliable way to accomplish this. Contrary to some claims, our e
Electronics Forum | Fri Jan 04 09:44:59 EST 2008 | philkaz
Hello, I am Philip Kazmierowicz and I work with KIC, a Thermal Profiling company. We have done many lifetime experiments on Printed Circuit Boards over the years. The key thing to understand is that if the primary material of the board in FR4 fiber
