Electronics Forum | Fri Jun 11 03:39:26 EDT 1999 | Gyver
| | | | Hello all! | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We doubt
Electronics Forum | Mon Nov 01 15:35:25 EST 2004 | Ken
Agreed. You will find different part manufacturers have different coplanarity specs. In fact I have on supplier that calls out 7 mil max coplanarity. Then factor in board bow and twist and it becomes a real joy.
Electronics Forum | Sun Apr 10 06:27:50 EDT 2005 | WarpSpeed
1.) First of all: What is Your customers requirements??? 2.) If the customer or You don't have a specification; I will strongly recommend that you follow the "IPC-IPC-TM-650 Method 2.4.22 Bow & Twist" that [DaveF] suggested. 3.) If You have "critic
Electronics Forum | Fri Apr 08 05:10:10 EDT 2005 | siverts
What is Your customers requirements? Is the PCBA mounted with front/back connectors? Will the PCBA be mounded in a rack and connected to opposite connectors on the other side? In this case, if the warpage is more than approx 1-1.5 % You will then n
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 Jun 10 14:52:55 EDT 1999 | Earl Moon
| Hello all! | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We doubt it's the pr
Electronics Forum | Fri Jun 11 04:38:05 EDT 1999 | Gyver
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Mon Jun 14 09:16:58 EDT 1999 | Adam Pratt
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Wed Apr 02 12:50:01 EST 2003 | rdr
Does anyone know of any standards that deal with the physical location of BGAs on a PCBA? I am looking for something that states to not put BGAs in the center Axis of assemblies for bow and twist reasons. We have always informed customers to locate
Electronics Forum | Fri May 07 20:08:39 EDT 2004 | Ken
...um also, don't forget that ther are planarity issues associated with BGA devices AND bow-and-twist issues with PCB materials. An example I have one BGA device that has a ball planarity of 7 mils!!! Ant that's the OEM specification! THis will re
