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Date: | Wed, 2 Feb 2005 13:01:41 -0500 |
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One of the factors that can affect thermal cycling results is if the boards
are tested after assembly and rework, or tested "as received". Materials may
be degraded with the thermal excursions of assembly and rework (particularly
lead free).
Also understand that boards fabricated with sequential lamination can have
reduced performance because internal material layers have already been
exposed to 2 or more thermal cycles in fabrication. Sequential lamination
would be typical fabrication method on boards with buried or blind vias.
Paul Reid
Program Coordinator
PWB Interconnect Solutions
613-596-4244 ext. 229
-----Original Message-----
From: Colin McVean [mailto:[log in to unmask]]
Sent: Wednesday, February 02, 2005 12:22 PM
To: [log in to unmask]
Subject: Re: [TN] Behavior of Via's in low temperature cycling
You may want to try the PCL370 HR product, which is more robust. Also
check degree of cure on the Turbo just to make sure. Call the Tech
Service guys, for help on the press cycle, and they'll check the sample
for you
Colin McVean
Production Manager
Artetch Circuits Limited
Tel: 01903 725365
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: 02 February 2005 17:12
To: [log in to unmask]
Subject: Re: [TN] Behavior of Via's in low temperature cycling
The material has a high Tg I believe in the 180 range and we had barrel
cracks but no cracks in the layers. The laminate material is a Polyclad
370turbo with a 2 ply core 8 mils thick with 6 layers. We cycled at 120
to -45degC . Failures were observed round 300 cycles of 125C to -40C.
Thanks for the interest in my situation.
Rich K/ KEDS
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Susan Mansilla
Sent: Wednesday, February 02, 2005 7:42 AM
To: [log in to unmask]
Subject: Re: [TN] Behavior of Via's in low temperature cycling
The test you describe is not a difficult test for today's product to
meet - do you know what type of failure you have? Corner cracks, barrel
cracks, inner layer separation?????
The Z-axis expansion of the laminate puts stresses on the laminate
system and the plating system.
Do you know what materials went into building the board (Tg etc)?
Susan Mansilla
Robisan Lab
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