Phil: U/V cure adhesives work well and are quite fast to cure. One down side
is they are usually higher in price than more conventional adhesives.

We have used both Dymax and Henkel/Loctite. The application was for
component securement prior to reflow. The products used are somewhat
thixotropic to prevent flow after application but are certainly dispensable.
The Dymax was their 621 and 921, the Loctite was 3526. 

Speed of cure is dependent on type of adhesive material, thickness of
deposit, light intensity, distance from light source and shadowing. But in
most cases less than a minute is normal. You can use spot or flood light to
cure. 

There are also variations of U/V adhesive if you have shadowing i.e. a
non-clear path for the light energy to reach the adhesive. In this case you
want one capable of secondary cure properties to continue to polymerize
after being initiated by the U/V light.


	
Regards
	
Michael Barmuta
	
Staff Engineer
	
Fluke Corp.
	
Everett WA
	
425-446-6076

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Phil Nutting
Sent: Monday, June 27, 2005 10:03 AM
To: [log in to unmask]
Subject: [TN] Light Cure Adhesives


Our current adhesive of choice is RTV.  Unfortunately it has a long cure
time and may be banned from use in products going to the European Union in
the coming years.
 
Our application is bonding 4 capacitors together.  The adhesive needs to be
thick (medium to high viscosity) so it won't sag, drip or run before curing.
UV cure would be best from a time standpoint.  A "glob" of about 1/4" should
be about right for this bonding application.  The capacitors have an epoxy
coating and the operating temperature is about 50° C maximum submerged in a
dielectric oil.  Electrical or thermal conductivity is not needed.  Method
of application is expected to be via small air actuated syringe or similar.
 
Anyone want to put in their 2¢?
 
Sales calls offline please.
 
Phil Nutting
Design for Manufacturing Engineer
Kaiser Systems, Inc.
126 Sohier Road
Beverly, MA 01915
voice: 978-922-9300 x1310
fax: 978-922-8374
e-mail: [log in to unmask] <mailto:[log in to unmask]>  
www.kaisersystems.com <http://www.kaisersystems.com/> 
 
 

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