Electronics Forum | Wed Dec 31 10:09:27 EST 1997 | Ken Daniels
| Has anyone had any experience with thermal shocking | and cracking of SMD capacitors during the rework process? | My company was advised to preheat capacitors to 125 C | at a rate of 2 C/sec before replacing them onto boards. | Would this maybe
Electronics Forum | Wed Dec 31 23:02:19 EST 1997 | Scott McKee
| Has anyone had any experience with thermal shocking | and cracking of SMD capacitors during the rework process? | My company was advised to preheat capacitors to 125 C | at a rate of 2 C/sec before replacing them onto boards. | Would this maybe
Electronics Forum | Mon Jun 13 18:47:56 EDT 2011 | kahrpr
Cracked parts close to the edge on pizza cutters are a common problem. There are a lot of stresses on the board as the blade cuts through the board. Raising the blade height so that the boards are not cut clean through will help. You will have to fi
Electronics Forum | Wed Jun 15 14:38:43 EDT 2011 | travishemen
Yes, both pads are the same distance from the edge. I also included a picture of a cracked part. Thanks,
Electronics Forum | Wed Jun 15 17:47:48 EDT 2011 | davef
Classic mechanical stress crack pattern. Pretty Try baking your boards for 2 hours at 100*C Minimum spacing between board features and v-score or break away is 30thou.
Electronics Forum | Mon Jun 13 13:35:08 EDT 2011 | travishemen
Hello, does anyone have any information on stress induced during V-score depaneling. We are using a machine with a fixed blade on the bottom and a free rotating blade on top driven by a motor. We have had some cracked capacitors on the edge of an a
Electronics Forum | Sat Jan 03 18:13:58 EST 1998 | David Jacks
Tom: You are right. Pre-heating is just as necessary in rework as it is in intiial production. Zephyrtronics produces an economical convective bottom side pre-heater known as an airbath. This product ramps the substrate and assembly at 2-4 degrees
Electronics Forum | Tue May 26 17:29:42 EDT 1998 | Earl Moon
| I know, I've read the "been there done that" stories about this subject, but I still profess ignorance on some aspects. | We are using NPO type dialectric caps in potted high voltage assemblies and continue to experience catastrophic vailures. U
Electronics Forum | Mon Sep 06 04:42:18 EDT 2004 | KenF
Thx for the replies. Acutally I am doing a process related study to see whether the process (pcb depanelling)can induce crack to an MLCC. After depanelling, I will do a thermal shock on the MLCC based on IEC 384-1, that is, five cycles of 30min at hi
Electronics Forum | Mon Jun 05 12:30:24 EDT 2017 | deanm
Mike, The dispensable solder paste is ordered separately from the printed paste because it has a higher flux content. I would not feel comfortable mixing liquid flux into the printable paste. Ask your paste vendor if they have a dispensable version.
