We assemble some pretty large boards that have 20 mil pitch parts as far as 28 inches apart on the diagonal. On a number of occasions we've had to order 'shrunk' stencils to match the boards. I've yet to run across a board that was 'stretched'. Your stencil vendor's photoplotter accuracy becomes rather critical for very large stencils. We measure the actual artwork on the boards and give the vendor a scale factor for each axis. Typically the scale factor will be slightly different in each axis. Cheers, Doug Ondricek Convex Computer Corporation > From: Kelly Kovalovsky, PCB Quality Engineering > ~ EMail:[log in to unmask] > Subject: PCB vs. Paste Stencil Comp > We have a fairly large circuit board that we are assembling. The card > has fine pitch SMT at extreme ends. We have noticed a mismatch between > the solder paste stencil and the printed circuit board. The circuit > board features are actually closer together than the stencil. > > My question to any card assembly site is whether it is common practice > to compensate a solder paste stencil for shrinkage of a PCB? > > IBM Microelectronics Division > 6800 IBM Drive MG12/251 > Charlotte, NC 28262-8563 > >