Electronics Forum | Sat Nov 18 21:20:58 EST 2006 | Fer
Dave, May I ask where did you find the 1.5%, or the goal of .005" (or .007") per inch? The IPC-A-600 bow and twist standard calls for a .75% based on the calculation of the test method TM-650, method 2.4.22, which calculates the percentage based on
Electronics Forum | Mon Nov 20 19:49:03 EST 2006 | davef
Sorry for stating this incorrectly. It should been: Bow & twist for bare boards and panels: IPC-A-610 Acceptability of Electronic Assemblies, 10.6: 1.5% for PTH only and 0.75% for SMT, acording to test method TM-650, method 2.4.22 IPC-6012, par. 3.
Electronics Forum | Thu Jan 30 01:38:22 EST 2014 | m_imtiaz
thank for good input, any documented standard available from any well known body (IPC standard)
Electronics Forum | Tue Mar 26 10:30:28 EDT 2019 | pavel_murtishev
Hello, Could you please tell me if there is any industry standard specifying QFN to PCB standoff after soldering? Is any gap allowed? Browsing IPC-A-610, I have found nothing. Any input would be appreciated. Regards
Electronics Forum | Wed May 16 14:09:22 EDT 2001 | davef
First thing I'd use is IPC-A-610C, �4.8.2 Connector Pins - Press-Fit Pins. Does it work in your case?
Electronics Forum | Sat Nov 18 08:42:11 EST 2006 | davef
Bow & twist: IPC-A-600. Acceptability of Printed Boards 1.5%; Goal 0.005" per inch; Practicle 0.007" per inch
Electronics Forum | Mon May 21 03:20:16 EDT 2001 | Abbas Izad
you can use IPC and Compact PCI standards for guideline then it depends on what kind of connector you want to pressfit. each supplier has its own design on pressfit pins like "needle eye", "baby H" etc... It is also importand to use proper equipement
Electronics Forum | Wed Mar 27 04:32:49 EDT 2019 | pavel_murtishev
Charliem, Thank you for the input. Following this logic, in case if there are no soldering issues, pad coverage and voiding levels are within acceptable limits and a gap between BTC and pad let us say 200um, this could be accepted, right? IPC-A-61
Electronics Forum | Thu Mar 28 13:19:14 EDT 2019 | davef
There is no industry standard for BTC stand-off height. "IPC-7093A Design and Assembly Process Implementation for Bottom Termination SMT (BTC) Components" just finished "Final Draft for Industry Review" in December 2018. It mentions stand-off height
Electronics Forum | Fri Mar 25 14:33:26 EDT 2011 | davef
IPC-7525 Stencil Design Guidelines
IPC is the trade association for the printed wiring board and electronics assembly industries.
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Bannockburn, IL USA
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