Manufacturing facilities using through hole technology on mixed technology boards sometimes struggle laying out lines in the most efficient manner.  Traditionally, SMT printing processes require that nothing protrude above the board surface.  The Accu-DotTM Stencil gives you the ability to print adhesive on SMT pads with existing through hole components inserted on the board.



The stencil is designed creating reservoirs on the top side with the laser cut apertures acting as the nozzle for adhesive deposition.  The bottom side of the stencil is machined so that when the stencil is lowered onto the PWB surface, gasketing can occur for accurate adhesive deposits.



Although blade printing is adequate in many cases, pump printing systems have the ability to generate the necessary pressure required to force adhesive through narrow diameter apertures.



Using a slow snap off setting achieves the best separation of adhesive.  Notice the adhesive does not cleanly release from the aperture.  This is normal and is what creates the ability to print different aperture heights for different components.



After component placement, the adhesive is cured, the board flipped and sent to wave solder.



During wave solder, both through hole and SMT components are soldered in one pass.



Illustrations courtesy of Speedline Technologies.