Dear KK
Single boards and fixtures are obviously one approach, but here's another:
One suggestion for your problem might be to go to a combination of score
and route with tabs connected to the board. This technique is usually used
with perforation holes to facilitate breaking he tabs just inside the board.
The perforation holes have the disadvantage of eating into the board space,
sometimes delaminating the board during breakout and also not leaving a
smooth edge on the board. On the other hand, if the tab connection to the
board is scored instead, it breaks consistently, with much less force,
leaving a smooth edge. There is still some concern about flexing the board
and cracking the SMT chip components, but with deep scoring, leaving 0.012"
remaining board, and a thin tab, you can make a board which breaks easily.
If you are interested in getting a JPG photo of an example of this, just
e-mail me directly. (I'm new on the Technet, and I don't know what the
protocall of sending attachments to the whole group is.)
Jeff Finger
Aimtronics Manufacturability Specialist
>>> jim <[log in to unmask]> 01/07 7:28 AM >>>
KK,
Give me a call or e-mail off line. I have made fixtures like this for a
couple of my customers and I might be able to modify the designs to meet
your needs.
Jim Gleason 972-494-1911
[log in to unmask]
-----Original Message-----
From: KK Chin <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, January 06, 1999 2:23 PM
Subject: [TN] Zero Margin PWB Assembly Depaneling
>Dear Technetters,
>
>We are designing a panel layout for a small PWB assembly (1.6" x 2")
which
>has through-hole components mounted very close to the board edge, leaving
>no margin for our usual depaneling process. We usually pre-score the
board
>and depanel with rotary-blade type splitter. We considered hand-splitting
>in this case but we worry about cracking the SMD's on the bottom. Can
>somebody enlighten me if there are any methods, tools or equipment for
>depaneling in this case?
>
>For your information, the PWB material is FR2, single-sided, 1mm or 1.6mm
>thick. Topside is all though-hole devices of 18mm max. height. Bottom
side
>is all SMD's of 1.2mm min. clearance to the board edge.
>
>Thanks!
>KK Chin
>Artesyn Technologies
>(510)683-6497
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