In populating an assembly panel, I have tried the mirrored array method before and successfully implemented it... I even tried boards in a sort of 'puzzle' configuration where no two boards were in any particular orientation but they fit real tight without any waste material... however... I think in retrospect this is one of those "pay me now or pay me later" type of cost savers in general... What I mean by that is even though you may save on board real estate you may find that the extra steps in assembly operations, programming, handling and special fixtures out weigh the cost of the little bit of material you loose in keeping all the boards oriented in the same direction and side. Something to weigh in choosing that solution... it might not be as good as it looks on the surface... so be careful... talk with your assemblers before you release it and get their opinion... Doing surface mount all on one side is preferable to mixed through hole and/or surface mount from both sides... Something to consider... Best regards, Bill Brooks - KG6VVP PCB Design Engineer, C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Datron World Communications, Inc. _______________________________________ San Diego Chapter of the IPC Designers Council Communications Officer, Web Manager http://dcchapters.ipc.org/SanDiego/ http://pcbwizards.com -----Original Message----- From: Dan Zammarelli [mailto:[log in to unmask]] Sent: Friday, July 29, 2005 11:41 AM To: [log in to unmask] Subject: Re: [DC] Standard panel size?... Another example of cost savings on the assembly side is to have a "mirrored" array. What this is , is an array of say 6 boards, 3 are in the normal or "component side" up position and 3 in the mirrored or solder side up orientation. This works best for a 2 sided reflow with a selective wave if needed type of layout. Since both sides of the board can be screen printed then components placed then reflowed during a single pass down the assembly line, only 1 solder screen is needed and 1 set of pick & place machines and one program for the machine's is needed. After the 1st pass through the line, the array is brought back to the start, flipped and then run through the line again. After SMD placement, I believe the arrays were then split in half to go thru the through hole and selective wave process. This is the preferred method at one of my former employers and it worked very well for them. Of course this method doesn't work for all applications, but when it is used, it can save a considerable amount of equipment cost, programming cost, floor space etc... Just thought I'd toss this out as a possible cost saving method. Cheers, Dan -----Original Message----- From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Chris Ball Sent: Friday, July 29, 2005 2:03 PM To: [log in to unmask] Subject: Re: [DC] Standard panel size?... Or 5MM or so inside if it's on a handling edge (breakaway rail or whatever). An interesting point was brought up earlier about rotation of components costing money. I don't dispute this, but... can a CEM give a finite cost difference accounting for this? I lose that argument with purchasing every time when being driven to squeeze more money out of a product. We can quantify boards in an array / arrays in a panel. So for example, we can say that for sure we save 5 cents per board if we rotate and nest PCB's in an array. We hear about it being a more complicated set-up, but... If we offer to take a 5 cent hit on the PCB we don't seem to get back 5 cents in the assembly cost, so we focus on what we can quantify. -Chris Terry Kozlyk <[log in to unmask]> To: [log in to unmask] Sent by: DesignerCouncil cc: <[log in to unmask]> Subject: Re: [DC] Standard panel size?... 07/29/2005 01:47 PM Please respond to "(Designers Council Forum)"; Please respond to Terry Kozlyk Very good thread !!! Also, don't forget that when placing your PCB onto a panel to ensure you don't have connectors which overhand the edge of the panel. Ensure that the PCB's are rotated such that the connector overhang is toward the inside of the panel OR ensure that the connectors ( right angle of course ) don't sit over the edge of the panel. Ensure that the edge of the physical connector becomes the absolute edge of the PCB within the panel. Regards TDK -----Original Message----- From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Brooks,Bill Sent: Friday, July 29, 2005 10:00 AM To: [log in to unmask] Subject: Re: [DC] Standard panel size?... Great discussion... I was talking with one of our board manufacturing vendors and he told me that they use 18 x 24 and 21 x 24 for quick turns and 20 x 26; 24 x 24 and 24 x 28 in higher volume production for standard lead times. I still don't exactly understand why but I can speculate that it may be related to their having a dual approach to supporting their customers needs... The normal production higher volume work may travel through the plant in a different way using separate equipment that can handle the larger panels and the quick turn work may take a path through their equipment that is optimized for those sizes and processes not commingling with the higher volume work... hard to say for sure... For some unknown reason long before I came here we settled on a standard assembly panel size of 10 X 12 inches and we have been designing our boards into them like that for the past 5 years that I have been here... It's not the most efficient use of a 18 X 24 manufacturing panel to be sure... That's why I am looking at redesigning the panel configuration to be more cost effective and still compatible with our assembly floor's capabilities... Higher yields... lower cost per board. Our solder paste screening machine has a limited depth of about 9.5 inches of travel and that limits the number of individual boards I can put on the assembly panel in either axis. Most of the other equipment, pick and place, washing, wave solder, axial and radial inserters, test equipment, hand stuffing second op workstations, etc...can handle larger dimensions. The screening station in our case is the limiting factor. Having a longer panel than 12 inches here does me no good. Some folks are making their panels 8.2 X 11.2 inches and fitting them 'four up' in an 18 x 24 panel with a .75 inch border around the perimeter and a .100 inch routed separation between them. Using V-scoring would gain an extra .050 on each edge of the panels if they weren't routed. This is quite doable since our assembly panels are always rectangular and with straight edges. We always orient the boards in our panels in the same direction so the programming for pick and place is easier and screening and reflow or wave soldering are consistent from board to board... Some vendors want more space between the individual assembly panels on their manufacturing panel and prefer an inch border and .4 between assembly panels for their tooling, fixtures, holders and test coupons. Making sure the panel size we end up with is efficient for ANY vendor we use is really my goal... and that does take a little research to find out what limiting factors are common among the vendors. So far it looks like the 8 X 11 size is pretty close to workable for most any shop and is fairly efficient use of the manufacturing panels they have... especially the 18 x 24 size... Then when we do our assembly panel designs we will have to package them into the 8 X 11 size (or whatever size we finally settle on) with all the needed fiducials, tooling holes etc...with clearances for machine holders, rails and such for our assembly equipment designed into them. Then my challenge will be to get the most efficient use of the space on our assembly panels... Thanks for the great comments Bill Brooks - KG6VVP PCB Design Engineer, C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Datron World Communications, Inc. _______________________________________ San Diego Chapter of the IPC Designers Council Communications Officer, Web Manager http://dcchapters.ipc.org/SanDiego/ http://pcbwizards.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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