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June 1999

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Subject:
From:
Glenn Pelkey <[log in to unmask]>
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Date:
Mon, 14 Jun 1999 09:30:31 PDT
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Iain,

Just some things to consider:

1)  Eye safety from the light source (protective goggles, warning signs,
training, company laser safety officer if required)
2)  Shadowing by the component.  That is, the material won't cure where light
can't reach it.
3)  Large CTE for this type of material compared with epoxy.
4)  Check for outgassing, viscosity, thermal breakdown, cleaning
compatibility, etc.  Process related activities I'm sure you'd do anyhow.

It would be fast.  The UV curable adhesives I've seen set in about 20 seconds
with the correct wavelength and intensity.

Not an endorsement, but you can talk to these companies:

Dymax
Emerson and Cummings (Grace Specialty Polymers)
Loctite
Master Bond
UVEXS, Inc.

Glenn

Iain Braddock <[log in to unmask]> Wrote:

| I would be appreciative of anyone providing an input into the use of UV
| curable adhesive for securing SM components to boards.  =20
| I'm thinking along the lines of gluing down ceramic QFP's on the
| assembly line for double sided assembly and was wondering whether a UV
| light source in line would provide sufficient curing of the adhesive to
| allow the board to be flipped for second stage assembly without any
| problems.  Is a special type of UV light required and how long does a
| cure take roughly, also any preferred suppliers/types.
|
| CIA Iain.

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