Electronics Forum | Thu Feb 03 10:01:08 EST 2005 | Philj
Try heating a blank board on a hotplate to 183 deg C. with a board this thick, if the layer construction is poorly balanced, it may bend enough in the region of the ceramic capacitor for the soldered joints to crack it on cooling to ambient.
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 | Wed Feb 02 08:51:25 EST 2005 | Dougs
we have a capacitor cracking on one of our boards, there are four of the same cap on the board and only one cracks, we are seeing about 6% of the component cracking. it's not near the edges of the board and he board is 2.4mm thick so i dont think it
Electronics Forum | Wed Feb 05 10:51:17 EST 2003 | bradlanger
Thanks for responding. Do you think I could have my oven profile too aggressive
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 | Mon Feb 07 08:34:46 EST 2005 | Dougs
we are still looking into possible causes, we have rigged up a test to determine whether the cap is cracked and have ran a controlled batch off of SMT, these were all tested and look OK. I'm looking into buying some small strain gages to place over
Electronics Forum | Thu Feb 03 07:53:51 EST 2005 | mmjm_1099
http://www.smtnet.com//forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=3628&#Message14433
Electronics Forum | Sat Feb 05 13:25:32 EST 2005 | etienne
Just a basic suggestion.... Inspect the nozzle placing the component...because that is the only medium, apart from the PCB design, which can be causing the damage. It occurred in my Department.
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
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