Electronics Forum | Tue Dec 17 20:25:13 EST 2002 | iman
Check : 1) design aspect ratio / are ratio required to fabricate the stencil you r using. 2) check if the stencil maker is using your checked aspect ratio / area ratio? if not the same, what are they using? any QA report confirming actual dimension
Electronics Forum | Wed Oct 04 09:55:51 EDT 2006 | borgie
Hi. I have product in lead containing process that consist lead free BGAs and also big ceramic BGAs with high temperature bumbs. Pcb tends to bow in a reflow profile, since I need long preheating times and relatively high peak temperature to melt BG
Electronics Forum | Mon Apr 19 10:14:12 EDT 1999 | Justin Medernach
| | | Hi, | | | I just cheesed my previous attempt at this. I looked through IPC 600 and couldn't find anything relating to dimensional stability of a board with regard to stretch. I found bow and twist but nothing on size. I have a PCB that is .0
Electronics Forum | Wed Jun 03 07:02:25 EDT 1998 | Earl Moon
| Does anybody know if a contraption exists that will minimize a PCB's tendency to become slightly bent after reflow? We have a new product that we're planning to assemble in a couple of months. The board is 9.7" by 13.4" and it is imperitive that
Electronics Forum | Thu Aug 10 13:12:10 EDT 2000 | Bob Willis
You may care to review the following from my Circuits Assembly page on line. "HOW FLAT IS FLAT AND DO WE NEED FLAT CIRCUIT BOARD, YES WE DO ? As production problems go there is one that keeps reoccurring time and time again. The blame is usually di
Electronics Forum | Mon Oct 03 22:12:53 EDT 2005 | davef
When we see warp and twist, we usually jump the fabricator for: * MLB construction (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selection (usually cheap and dirty), etc. War
Electronics Forum | Sun Aug 08 11:15:32 EDT 1999 | Earl Moon
| | Mike, | | | | Got your message and those of others concerning PCB fab supplier evaluation and qualification check lists, etc. I have a severe problem here in WI as I can hardly access the internet, and when I do it is cut off abruptly for no goo
Electronics Forum | Sat Aug 03 07:29:20 EDT 2002 | davef
IPC-PE-740 "Troubleshooting for Printed Board Manufacture and Assembly" has words to the effect of � 1.5---BAKING Laminate materials are baked several times during the manufacture of a printed wiring board. There are four major reasons for
Electronics Forum | Thu Jun 25 14:41:07 EDT 1998 | Earl Moon
| Alright gentlemen and ladies of the forum, I again seek knowlage on what is probably a well known fact. I have spent a good part of the morning with various IPC standards and weighty tomes such as the Electronic Packaging and Interconnection Handb
Electronics Forum | Fri Jun 26 11:27:12 EDT 1998 | Earl Moon
| | Alright gentlemen and ladies of the forum, I again seek knowlage on what is probably a well known fact. I have spent a good part of the morning with various IPC standards and weighty tomes such as the Electronic Packaging and Interconnection Han
