Electronics Forum | Thu Feb 03 04:55:21 EST 2005 | Dougs
OK, component wide portion runs with the conveyor, so really both sides should heat and cool at the same rate. The crack is at the termination between end cap and ceramic body and run vertically up the end cap, so when we remove the cap it comes of
Electronics Forum | Thu Feb 03 12:21:15 EST 2005 | Chunks
Lets get to the simple things. Wave or Reflow? Wave soldered parts have a higher susceptibility to physical damage until they are waved. That�s were I normally see this type of break. Usually, the crack is a circular pattern in the cap if it�s fr
Electronics Forum | Wed Feb 02 20:00:48 EST 2005 | davef
150*C/min * Determining the distance it takes to lower the delta temperature at the current conveyor speed: [150*C/min]/[25 inch/min] = 6*C/inch * Calculating how much of this 6*C/inch would be spread along the length of the 0805 capacitor: [6*C/inch
Electronics Forum | Thu Feb 03 07:39:24 EST 2005 | davef
The component orientation was just for the calculation. It has no affect on what you're seeing. As an alternate explanation, it's possible that difference in temperature is causing the board to flex in the z-direction [as you say, it may not be f
Electronics Forum | Fri Sep 03 11:45:15 EDT 2004 | rlackey
Hi Ken, I know this doesn't help in the immediate timescale, but isn't avoidance the best form? can you trace the cracking to a process issue (Solder profile, shock damage, handling damage, probe/ATE damage)or a chip cap manufacturing fault? I can'
Electronics Forum | Thu Mar 14 09:07:26 EST 2002 | cfraser
I can not tell you what the actual stress limits are. I can tell you that de-paneling PCB's by hand is a very poor choice. I have seen numerous accounts of cracked caps, resistors, and LED�s due to incorrect de-paneling procedures. I would recommend
Electronics Forum | Sun Dec 02 20:02:23 EST 2007 | chs
Hi, There are QFN 32,40,48 pins with middle pad. Body size are 7x7 and pitch 0.5mm. I means as compared to 2 sided package, QFN are easily damaged by external mechanical / thermal force. Phenomenon observed are mold cap open which further caused wire
Electronics Forum | Tue Jun 22 00:20:21 EDT 2010 | leadthree
Pick & Place > Wave-solder > other parts > test > conformal coating Is there any production error that could make a ceramic cap conductive? PS: want to add one point: The caps don't seem to be cracked. We changed a few 100 and didn't notice any bro
Electronics Forum | Thu Jun 24 11:21:40 EDT 2010 | floydf
Hi, > > I have a 100nF 0805 ceramic cap (the most > common type!), Yageo brand (20+ pcs. on the > module). In our production run I get some errors > due to conductive caps (can be anything from 25 > Ohm to 5K - most are open of course). Only one
Electronics Forum | Mon Nov 07 12:25:32 EST 2005 | Rob
Hi CW, Larger chip caps can be susceptable to cracking, but mainly this is due to handling - flexing of boards is the main culprit (the part being mechanically joined at both ends to the board). PCB's usually flex easiest along one axis, and larger
