Edi,
        here are a couple of suggestions that I could make.

1)      I would reduce your perforations to 4 drill hits evenly spaced per
tab.
2)      You mention it is mixed SMT and Thru hole. Is it to be wave
soldered? Wave soldering severely weakens the tabs while the board is hot
and the boards may submarine in the wave if the panellized boards droop too
much. IS there a chance for a board carrier if you are wave soldering the
Thruhole parts.
3)      I would align the top and bottom tabs vertically. Then if you do not
have an issue with wave soldering, the board can be packed nearly edge to
edge with a single router pass between two rows of boards (a number of
additional boards per panel, greater efficiency (no frame between boards)
and reduced cost per board).
4)      Border? At the edge of the panel or around each PCB?
        At the edge of the panel it is up to the PCB fabricator. Most
fabricators are fine with 1 " panel edges, some may allow you to go down to
1/2".
        Around each PCB it is an assembly issue. Again it partially goes
back to are you wave soldering. If you are wave soldering you will want more
frame to support the boards when the panel is heated. If you aren't wave
soldering, can you put the boards nearly edge to edge with no frame, just
tabs between them. You should check with the assembly house for other
assembly issues particular to your assembly.

Sincerely,
Brad Velander.

Lead PCB Designer
Norsat International Inc.
Microwave Products
Tel   (604) 292-9089 (direct line)
Fax  (604) 292-9010
email: [EMAIL PROTECTED]
http://www.norsat.com


> -----Original Message-----
> From: Edi Im Hof [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, January 21, 2003 1:04 PM
> To: Protel EDA Forum
> Subject: [PEDA] perforation
> 
> 
> 
> Hi all
> 
> I'm curently designing a panelisied pcb. The panel is not the 
> problem, but 
> the break-away-tabs (or however they are called)
> 
> I've created following thing:
> http://www.ihe.ch/temp/nutzen.pcb
> 
> The large pads indicates the start/end points of the router bit.
> 
> Is the perforation to strong / to weak / exactly right?
> How wide should the border be?
> This is a 1.5mm FR4 two sided mixed smd/th board.
> 
> The break excess should be less than 0.5mm
> 
> Any comments?
> 
> TIA
> Edi Im Hof

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