Electronics Forum | Fri Jan 07 07:36:14 EST 2005 | dansmall
I have a Polyimide board that is showing signs of de-lamination. I was wondering what pre-bake times and temperatures other people would recomend for new boards as well for boards that have been on the shelf for 8 months.
Electronics Forum | Wed Jan 12 10:05:20 EST 2005 | Dreamsniper
we are using polyimide boards 6 inches x 7 inches, 2.5mm thick, 12 to 14 layers, for aerospace industries. I am using a long bake of 12 hours at 70'C prior to manufacturing or exposure to elevated reflow and wave soldering temperature. If schedule i
Electronics Forum | Sat Jan 08 08:50:35 EST 2005 | davef
Normally, you should not have to bake boards that are properly packaged and stored. Since you are seeing problems, baking makes sense. Consider 125C for 4 to 6 hours. Additionally, look here for more, while waiting for others: http://www.smtnet.
Electronics Forum | Fri Oct 22 04:09:22 EDT 2004 | christina
Is there anyone who knows the yield rate difference for SMT on multi-flex boards and rig-flex boards ? Basically, I think the yield rate should be higher for rig-flex than multi-flex due to the poor dimensional stability of polyimide, since multi-fle
Electronics Forum | Fri Apr 06 08:27:09 EDT 2001 | CAL
From what you are saying................If I hear ya correctly - There is no "Proctective" on the Pads (OSP, HASL....) You will be hard pressed soldering to bare copper. This can not be right. My suggestion- go polyimide with electroptical connecti
Electronics Forum | Thu Feb 25 07:37:42 EST 2010 | pcbrown
We are using Humiseal 1B31 and polyester dots for masking. We are spraying this in a Binks sprayer mixed at almost 1:1 with 521 thinner. Whe are seeing the coating creating thin halos around the poly dots as if the dots are "rejecting" the coating. T
Electronics Forum | Thu Dec 10 09:09:31 EST 1998 | Earl Moon
| Hi everybody? | I heard that typical FR-4 would not acceptable for BGA application. | What is the main reason? | (thermal property? or CTE?) | Sombody please answer me the requirement of PCB substrate for PCB application. | Thanks. | | Youngho Son
Electronics Forum | Fri Oct 22 11:53:53 EDT 2004 | C Lampron
Hi Christina, What would you be basing the yields off of? Is it solder defect, component placement, etc....? I have worked for a flex house for quite a few years. You are right. The Polyimide is very dimentionally unstable. (even more so on humid da
Electronics Forum | Fri Oct 13 13:44:03 EDT 2000 | Mike McMonagle
You can achieve a wide range of dot heights when stencil printing by using a polyimide stencil along with a .040 snapoff. Loctite has a system for this that they call Varidot, by varying the size of the apertures in combination with the .040 snapoff
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