Electronics Forum | Tue Aug 28 08:28:30 EDT 2012 | rgduval
We agree with all of the previous comments, and would add the following: Warpage is generally caused by excess moisture in the raw boards. Have you tried baking the boards prior to assembly? We had this issue on a simple 4-layer board, and found t
Electronics Forum | Thu Oct 14 20:42:07 EDT 1999 | Jeff Ferry
Grace, As deifned in IPC 7721 Procedure 3.2 Bow and Twist Repair "Bow and twist after soldering shall not exceed 1.5% for through hole PC boards and .75% for surface mount PC boards. The bow and twist shall not be sufficient to cause difficulties d
Electronics Forum | Thu Aug 09 07:53:16 EDT 2012 | davef
Allowable bow & twist: Together, both IPC-A-600G and IPC-6012B represent the core IPC documents for describing the acceptable and nonconforming conditions that are either externally or internally visible on finished printed boards. IPC-A-600G relies
Electronics Forum | Thu Apr 07 10:58:01 EDT 2005 | Dhanish
Need help from the experts on 1)simple way to measure the PCB warpage 2)what is the maximum warpage can the SMT machine allow the to accept and place the component without problem. 3)I have seen some people are using 7mils/inch as a Warpage spec. a
Electronics Forum | Thu Apr 07 20:16:23 EDT 2005 | davef
Q1) Simple way to measure the PCB warpage A1) IPC-TM-650; Method 2.4.22 Bow & Twist Q2) What is the maximum warpage can the SMT machine allow the to accept and place the component without problem. A2) That depends. IPC-A-610 Acceptability of Elect
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 | 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 Feb 28 09:08:03 EST 2003 | davef
Without drilling through the numbers, they're probably correct. Recognize that standard warp / twist specs [IPC-A-610 1.5% for PTH only and 0.75% for SMT] are not going to make it on tech boards. You need to define specific requirements. This warp
Electronics Forum | Wed Aug 19 12:20:24 EDT 1998 | MARK J.
| Hi there, | I'm actually facing a lot of trouble with PCB's presenting up to 3mm of bow /twist at reception i.e. before assembly. The PCB size is 220 by 230mm. The boards are to be assembeled SMD double sides with 05.mm pitch on both sides. In orde
Electronics Forum | Sat Jan 14 06:38:04 EST 2006 | DannyJ
Hi Ken, Good question, and I did search for what you are asking, but unable to find anything conclusive about using tacky flux vs. solder. In reliability, it depends on which section of the process you are talking about. Mainly (and there are sev
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