You are looking for specific answers to general concerns. Given the
amazing number of suppliers and possible product choices can only
really help by giving general comment which will help dimension the
size of your concerns.

Generally....
Outgassing can occur on cure during assembly and on thermal cycling
during use.

Assembly outgassing is a concern in this type of application as it
will lead to voids. Bubbles (voids) are not particularly conductive
nor very adhesive. This is more of a concern than the fumes which seem
to be the focus of your concerns. Naturally you will be using this
product in a well ventilated area avoiding skin contact and so on.
Check your data sheets for weight loss on cure, you will see/ensure
that the numbers are small, by using solvent free products and so on.
Then consider these numbers in the context of the amount of product in
the bondline and this will help answer most of your questions in the
health and safety etc areas.

In service outgassing  usually occurs whenever the temperature goes
above the original cure temperature.

Supplier data sheets will contain information or they will have test
data on voiding /outgassing so find a friendly one for a chat


Mike

----- Original Message -----
From: "Sue Hedrick" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, July 25, 2000 10:51 PM
Subject: [TN] Outgassing -- not a space application


My company is qualifying an adhesive film to be used in bonding a PC
board to a metal plate. As the film is silicon based, our customer is
worried about outgassing. The adhesive vendor has agreed to have tests
run (at no cost to us), but we need to supply the requirements.

By the way, this is not a space application. The equipment that this
bonded board will be used in needs to operate from -40C to +85C.

My questions are:

1. Under what conditions is outgassing a concern?

2. Is condensation and leaching a concern at lower temperatures?

3. Are there any flammable vapors that we need to be concerned about?
Or any environmental or health hazards, either during assembly or
during operation?

4. In addition to corrosive effects, are there any concerns about
degradation of the electrical characteristics due to contamination of
the boards?

5.  What specific compounds cause these problems?

6. Is there an industry standard for spec limits under these
conditions?

Thanks in advance for your help.
Sue Hedrick
[log in to unmask]




Mike Fenner

 T: +44 1295 722992
 F: +44 1295 720937
Visit: www.lasercuttingco.com

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