FR4 has been punched for years. I first worked in Asia in 1985 and worked in
Asia for over 14 years. Almost all of work is punched except for
multi-layers because of the fracturing between layer concern. If the
supplier has good controls they count the number of hits and resharpen the
tools. Layer count, board thickness and dimensional tolerance should dictate
to them if they can use a punch press or not.

Scott Westheimer
----- Original Message -----
From: "Greaves, Bernie (IMP)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, February 16, 2005 10:54 PM
Subject: [TN] Cracking FR4


Hopefully someone in the forum may have had experience with cracking
along edge of FR4 as per attached photo. The profile of this pcb was
punched and subsequently the edge has fine cracks through the soldermask
and glass. We have had a large quantity of this part made in China and
are concerned that this cracking could compromise the board function.



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