After reading my reply once more I realized I left out a detail... in order to make the gap thinner here we have to use a thinner cutter blade on our depanelizing tool, one that matches the gap in the panel. It's a custom made cutter but they aren't very expensive to make, they are tooled out of sheet metal steel and shaped like a 1 inch by 3/4 inch hook. The pneumatic cylinder that pulls it down against the work surface and through the board web cuts right through the board like butter and is very strong and operated with a foot pedal. The board is very cleanly sheared and creates no dust like the router bit or Dremel tool abrasive wheel cutter versions I have seen. It's actually a very efficient way to deal with the issue. Bill Brooks - KG6VVP PCB Design Engineer , C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 e-mail:[log in to unmask] http://www.dtwc.com http://pcbwizards.com -----Original Message----- From: Brooks,Bill [mailto:[log in to unmask]] Sent: Wednesday, January 26, 2005 8:46 AM To: [log in to unmask] Subject: Re: [DC] Web routing widths Hi Gary, Here we chose a .100 in. wide gap between the board and the panel with a web that is .100 in thick plus or minus .020 in. The reason for that choice was based upon 2 factors. One, the board house that manufactures our board likes to do the panel gap with a single pass of the router bit and they prefer the .100 wide gap so they can use a larger router bit. If I had a board that has need of a smaller radius on right angle cuts than .050 in. I would probably reduce the gap to let them make the run with a single pass and a smaller router bit. The second criteria for driving the decision to us .1 and .1 is our assembly group uses a 'depanelizing' or 'singulation' tool that is optimized for the .100 width web... It was designed to be used similar to a sheet metal 'nibbler' tool and cut the web out in a single hit. The width of the cutter just fits into the slot between the boards leaving very little flash after the cut is made. There are many other methods of depanelizing boards and those methods should be taken into consideration when design your assembly panel. There are actually some IPC guidelines published in IPC-SM-782 section 3.6.4.6. Figures 3-29, 3-30, 3-31 and 3-32 give good examples of assembly panel construction. I think you will find them informative. If you have taken the CID workshop and exam you will find the info on page 117 and 118 of the Study Guide. Best regards, Bill Brooks - KG6VVP PCB Design Engineer , C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 e-mail:[log in to unmask] http://www.dtwc.com http://pcbwizards.com -----Original Message----- From: Gary Koven [mailto:[log in to unmask]] Sent: Wednesday, January 26, 2005 8:00 AM To: [log in to unmask] Subject: [DC] Web routing widths Forgive me if this seems arcane, but we've become interested in the different web routing widths that our assemblers are telling their fabricators to use to panelize/depanelize our boards. We've seen 0.125 inch, 0.093 inch, 0.062 inch, and 0.050 inch wide webs thus far. 1. Is there one IPC standard, or a combination of IPC standards, which specifies preferred web routing widths? 2. How does an assembler determine a "sweet spot" for each preferred web routing width whereby the individual boards will depanelize most easily? 3. Which preferred web routing width yields the lowest cost route? Best Regards, ====================== Gary M. Koven, C.I.D. Engineering Services Manager Dynazign, Inc. 806 Tyvola Road, Suite 100 Charlotte, NC 28217 P: 704.405.1234 x210 F: 704.405.1402 http://www.dynazign.com/ ---------------------------------------------------------------------------- ----- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. 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