Electronics Forum | Mon Mar 03 11:07:40 EST 2003 | MA/NY DDave
Hi In addition to what DaveF gave you which you should look at first Search the archives for warp bow twist warpage etc. A Lot of treads exist. Many of the larger OEM's and even the Mil have historically created their own documents for acceptable
Electronics Forum | Mon Feb 02 16:42:03 EST 2004 | davef
Bow & twist for bare boards and panels: IPC-A-610 1.5% for PTH only and 0.75% for SMT. So, what are you doing to these poor boards to make them warp?
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 Dec 12 15:34:59 EST 2002 | msimkin
Has anyone had any expereince with FR4 boards under the std 0.5% warpage for Bow & twist with CSP & uBGA devices on them that have caused failures. Are there any revised percentages for boards loaded with these devices that anyone knows of, istead of
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 | Tue Aug 10 09:01:18 EDT 2010 | davef
No, warpage tells you that design and/or fabrication process and/or assembly process need[s] to be corrected. Here's a link to a recent thread on SMTnet that seems to answer some of your questions: http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Mess
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 | 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 | Wed Jul 21 11:12:05 EDT 2010 | remullis
I have some 13" long boards that warp considerably during first pass through reflow (no center support), what I've done to improve this type of warpage is stiffeners along the front and back edge. This may help with twisted boards as well.
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