Tom,

As I remember, CEM 1 is a lesser flammability rating than CEM 3 or FR4. CEM
1 may even be paper base. CEM 3 is a 94 V-0 rated epoxy base but it is built
with only Glass B-stage on the outside of the construction. The center
dielectric is more of a mixed resin. Im sure others can give you a more
detailed explanation. FR4 is you basic epoxy laminate manufactured with plys
of glass cloth prepreg throughout the construction. CEM 3 is Type materials
are becoming  popular for parts manufactured with score lines. It is easier
to snap out of a panelized array since there is no glass cloth in the center
of the dielectric.

Ed Cosper
-----Original Message-----
From: Tom Burek <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Tuesday, May 25, 1999 6:05 PM
Subject: [TN] Compare CEM-1, CEM-3 and FR4


Can anyone tell me what CEM-3 is?  How does this differ from CEM-1 and FR4?
Is there a WEB site that list this information in one site?
Thank You,

Tom Burek
[log in to unmask]

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