Stencil is the stanless sheet and cutting hole via Laser Cut machine can select the thinkness of the stanless sheet. It must used in the SMTA machine in the solder paste printing process.
The stencil will have the in the SMT machine will have the conveyer it’s can adjust the distance and fixed the stencil in the machine. The thinkness of stencil concern about the volume of the solder past if we choose the thin plate PCB Assembly the solder joint is small (fillet it’ small ) if used with the big pattern it’s will be defect it’s call insufficient solder and effect to the effitency in the long time.
If we choose thick stencil it concern of the solder volume it will be much more solder it’s has the chance to the defect (Solder ball, solder bridge). You should
be select the thickness to suitable of the footprinted patern (copper pattern)
it’s will be increase productivity (Decress Repair times, man power) and decrease cost (Decrease Sub material). For the tolerance of the copper pad it been 80-90% of all pad area. After pass the reflow process solder joint it’s perfect.
Process engineer will be have the knowledge about the design stencil it will help to solve problem concern the in line SMT defect. Stencil desing good will can help to solve the defect sush as solder ball, solder bridge, of more detail you can learning the IPC it’s define all detail about the design stencil.
