Electronics Forum | Sun Apr 05 09:46:47 EDT 1998 | Earl Moon
| We are looking at reflow soldering some Flexi-rigid | pcbs. I have heard that IR reflow soldering can make the Polyimide "self heat" and cause de-lamination. | Does anyone have any info. The thermal problems associated with polyimide rigid/flex de
Electronics Forum | Fri Jan 21 14:51:08 EST 2000 | Dave F
Mike: I�d hate to see you making design decisions, based solely on the discussion here, but that this would be an impetus to consult IPC-D-279, "Design Guidelines ... " and take a course on designing reliable boards. Werner Engelmaier (Engelmaier
Electronics Forum | Tue Aug 25 16:28:11 EDT 1998 | Al Knudson
Hello, Our PWB supplier has requested that a change in the laminate material to reduce the incidence of pad lifting. The standard laminate materials (Polyclad PCL-FR-226 with a glass transition temperature of 135 C) have greater z-axis thermal expan
Electronics Forum | Sat Dec 13 17:46:27 EST 2008 | ysutariya
If you're military then you're probably just needing standard 130Tg FR4 and tin-lead finish. I would check two things: 1. Bake temperature: Isola recommends 300F for 4 hours to drive moisture out. Lower baking temperatures do not require a linea
Electronics Forum | Tue Aug 25 17:49:15 EDT 1998 | Earl Moon
| Hello, | Our PWB supplier has requested that a change in the laminate material to reduce the incidence of pad lifting. The standard laminate materials (Polyclad PCL-FR-226 with a glass transition temperature of 135 C) have greater z-axis thermal e
Electronics Forum | Thu Aug 17 22:22:29 EDT 2000 | C.J. Long
Hi erverybody: I am from a PCB shop. One of our product is with 19 X 19 ceramic BGA and my customer is experiencing 0.1 - 04 % failure of open trace on cornoer BGA pad. Substrate is FR4 with TG 135 degree C and delta Tg is well below 3 degree C. Tra
Electronics Forum | Mon Feb 15 15:33:47 EST 1999 | Earl Moon
| Any info on the pros and cons of FR4 or Polyamide ref the use of soldering PGAs would be helpful. ie. temp co-efficient diffs, baking, wave soldering, Convection reflow etc | I'm sure you know all the basic differences as Tg, X, Y, and Z expansi
Electronics Forum | Fri Jul 29 19:12:30 EDT 2005 | Jason Fullerton
In the true sense of the term, tombstoning can only occur during reflow. Now, if your solder joints are cracking during thermal cycling and opening on one end you still have a problem - it just isn't "tombstoning". What laminate are you using on yo
Electronics Forum | Wed Oct 19 07:04:06 EDT 2022 | winston_one
If any changes in design is not possible and you have to solder it, it's a real headache, I know... I see only 3 options here that you can try consiquently: 1) Accurately profile the board and optimize a profile (go to lower limit of process windo
Electronics Forum | Wed Mar 18 09:03:57 EST 1998 | Earl Moon
| Problem occurs because the glass transition temp for FR4 is lower than reflow temperature. Our company wrote an article which was printed in SMT magazine some years ago | that deals with this exact subject. Best way to deal with this is to use a ce
