In cases like this (the joys of contract manufacturing) we have had carrying pallets made, for more like $250 each. We had one board that was donut shaped, can't do much with that! Using a carrying pallet will increase the handling time, but is likely cheaper than re-spinning the PWB. regards, - Graham -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Landman Sent: Monday, February 20, 2012 2:47 PM To: [log in to unmask] Subject: Re: [TN] Sanding board edges after reflow Thanks Amol. The CM just told me that he can get a custom fixture made to grip the boards but it costs $850 (I guess thats an "each" cost) so I'll pass to him your suggestion. Bob Sent from my iPhone On Feb 20, 2012, at 11:40 AM, "Amol Kane (Asteelflash,US)" <[log in to unmask]> wrote: > Hi Bob, > While your CM is doing what is very common in the industry (adding SMT > rails for manufacturability), I would be concerned with the ESD > implications of sanding, as well as FOD on the assembled product. > Furthermore, We do not prefer tab routing (mouse bites) due to the > shock/impact to the board during de-paneling. > > I would recommend you investigate a scored/routed rail that can be > de-paneled on a pizza cutter. If there are overhanging components on > the assembly, you may not have a choice. But, careful design of the > mouse bites, and the tooling thickness can still eliminate the need to > sand the edges after de-paneling > > Regards, > Amol > > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Landman > Sent: Saturday, February 18, 2012 2:23 PM > To: [log in to unmask] > Subject: [TN] Sanding board edges after reflow > > Our contract assembler just sent us the following message for a short > prototype run on a modified design: > > ------- > > "I asked the board house to add a 1/4" tab routed strip on the long > side of the board that P1 is on so that we can put solder paste and > place all of the top side SMT parts. We need at least 4mm (0.160") > for the clamping rails on the machines. C180, C181, D1, R19 and C27 > are to close to the edge of the board. > > We will remove the strip and sand the tabs." > > ------------ > > It's a 6" x 8" 6 layer board (Sn63 soldered) with SMT parts (including > a > 256 ball BGA and a number of tiny QFN parts). Apparently the EE who > designed the changes and the PCB layout person were very tight on > space so extended circuitry into the area reserved for the reflow > oven's grippers. > > Should I not be concerned that sanding could cause cracks in the solder? > The EE told me, as did the assembler, there was nothing to worry about. > > This is the first time this problem has occurred since we began making > products in 1980. > > Should I pull the job (which is a 5 day turn) on Monday and have the > artwork fixed to provide gripping areas (which used to be there) ? > > Or is it safe to do what the assembler had told the board fabricator > to do? > > Bob Landman > > Sent from my iPhone > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud > service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________