Electronics Forum | Wed Nov 25 12:33:16 EST 1998 | Scott Snider
| A buddy of mine has problems after depaneling double sided pre-scored PCB's. Resistors near the edge, after put into the slice and dice machine contain micro cracks. He's checked for them before and after depaneling. We figure it is the sectioni
Electronics Forum | Wed Nov 25 17:21:17 EST 1998 | Michael Allen
A word of caution: thick webs (i.e., shallow score grooves) can result in scrapped boards, especially if you've got the dual-wheel-type score breaking machine. I discovered recently that shallow score grooves, combined with DULL knife-edge guides on
Electronics Forum | Wed Jun 25 18:35:28 EDT 2003 | Brian W.
Most of the time, Ceramic cracks are cracked due to mechanical stress. Check your depaneling methods. Cermaic caps that are close and perpendicular to the board edge are especially susceptible.
Electronics Forum | Mon Jun 21 12:02:36 EDT 2010 | roland_grenier
check your de-panelling process if you are using break-out tabs or V scoring.
Electronics Forum | Fri Apr 18 16:53:25 EDT 2003 | takfire
DST, What was the crack signature? Was the crack parallel with the internal electrodes or 45� with the terminal electrode? It is also important to determine the orientation of the failed caps on the PCB (in regards to depaneling). Perhaps the cap
Electronics Forum | Fri Apr 18 19:15:49 EDT 2003 | adlsmt
Please elaborate on "De-paneling method" vs. boards being "snapped out of thier pannel". Read the last post before mine again.
Electronics Forum | Fri Jun 20 11:05:53 EDT 2003 | russ
Why don't you give us the full process along with your delta T for the wave (final preheat temp to wave contact temp). Don't forget de-paneling, ICT, and other things. It could be from the supplier, but it usually is from excessive placement force
Electronics Forum | Wed Jul 02 18:39:22 EDT 2003 | Jim Yutzie
The vast majority of issues I have seen are from depaneling with a PCB seperator. Try placing a row of tightly spaced unplated holes adjacent to the edge that the crack parts are being found out (assuming they are within .5" or so of the score line)
Electronics Forum | Mon Jun 30 10:52:36 EDT 2003 | Bob
Suggest you ask vendor for a failure analysis. Ceramic chips have specific signatures for mechanical or thermal shock cracking. The vast majority of failures are due to mechanical flex. Depanelization and secondary operations such as hand insertion
Electronics Forum | Fri Jul 09 19:09:52 EDT 2010 | rway
A couple of things: Does the cap break if you try to remove it with hot air? If not, than you are breaking the caps do to mechanical stress. We have had similar issues. I don't think your board is suffering from mechanical stress from depaneling o
winsouce.jpg)
