Electronics Forum | Mon Aug 06 17:29:07 EDT 2007 | gsala
Hi Gents, I heard people having concernes by using 2512R SMD resistors due to potential solder joint reliability defect(CTE mismach among ceramic/alumina+solder+PCB) when soldered by lead free alloys (SAC like). Any experience/news about solder j
Electronics Forum | Mon Aug 13 12:03:50 EDT 2007 | davef
Test results indicated that the life of lead-free solder at a 2512 chip resistor could be worse than of SnPb solder in the accelerated thermal cycling condition. [Development of Life Prediction Model for Lead-free Solder at Chip Resistor, Changwoon H
Electronics Forum | Wed Aug 15 01:30:56 EDT 2007 | wayne_
To be more specific. I am actually talking about the electrical fatigue whereby a unit is undergo a cyclic electric test. Unlike thermal fatigue, it is all talking about temperature related testing, eg, ageing test, thermal cycle test, etc. Anyone of
Electronics Forum | Thu Aug 09 19:13:37 EDT 2007 | htran
DaveF, Our customer requirement is to comply with IPC-STD-001 but the J std doesn't specify the bake out temperature for populated boards and the moisture absortion rate. Right now we are baking the populated PWAs after aqueous wash at 80C at 18-48
Electronics Forum | Tue Aug 14 19:49:21 EDT 2007 | htran
My apology for not mentioned the J-STD-001DS. I didn't mean to trick you. Anyway thanks for your inputs. You are the man with the smt knowledge, I am sure that I will be asking you for some more answers again. Thank you for the link. I will loo
Electronics Forum | Fri Aug 17 17:55:42 EDT 2007 | htran
My small reflow oven doesn't have the rails (only metal mesh). I personally don't think it was built for double side reflow assembly and there is vibration as well. We are a small low volume mfg house and our reflow oven doesn't have the capability t
Electronics Forum | Sat Aug 18 08:40:34 EDT 2007 | davef
Here's how to double reflow your QFP: * Reflow the first side with the QFP according to plan. * Paste second side and place components according to plan. * Lightly crinkle a small, QFP-size piece of aluminum foil. [Note: the degree of crinklization
Electronics Forum | Wed Aug 22 14:28:56 EDT 2007 | russ
our biggest problems with these parts is them laying on their sides after placement with a certain machine that we have. make sure that you do not have a planarity issue as well menaing that the leads are indeed below the body of the component. I a
Electronics Forum | Wed Aug 22 16:11:15 EDT 2007 | razor1
If the problem appears to be random... we had a similar problem. We found that the belt which feeds the PCB through the reflow oven would jump or lurch ahead. It was barley noticeable but if you have identified the frequency and time of the compone
Electronics Forum | Wed Aug 22 16:23:06 EDT 2007 | rgduval
I had the lurching issue...turned out I needed to readjust to cog wheels on the exit side of the oven. The cogs had slipped, and the chain was actually getting caught in the teeth...to the point that as the wheel turned, the chain would stay in it i
