PCBA need stencil ,Why ?

  A PCB Stencil is a sheet of stainless steel with laser-cut openings used to place solder paste on a PCB board for surface mount component placement. The PCB stencil is used to deposit solder paste on designated places on a bare PCB board so that components can be placed and perfectly aligned on the board.

  Its main function is to accurately deposit the right amount of solder paste on SMT pads so that the solder joint between the pad and the component is perfect in terms of the electrical connection and mechanical strength.

   Using a PCB Stencil to apply solder paste makes the pcb assembly process faster. It also makes it easier to apply solder paste accurately.

   During the pcb stencil making process, the opening or aperture wall becomes rough due to the constant application of laser beams. This happens because the laser beam tends to melt the sheet material, which leads to some surface abnormalities called micro-burrs in the aperture wall. To solve this problem, electropolishing is performed to smoothen the aperture wall. It promotes the easy transition of solder paste from the stencil to the intended PCB pads.