PCB Stencil
The primary purpose of the PCB stencil also called as steel mesh, is to facilitate the application of solder paste and transfer an exact quantity of solder paste to an exact location on the bare PCB. Steel sheet, wire mesh, and stencil frame make up the stencil. Steel mesh also referred to as PCB stencil. Its primary purpose is to facilitate the application of solder paste and transfer a precise quantity of solder paste to the precise location on the bare PCB. Steel sheet, wire mesh, and stencil frame make up the stencil.
There are numerous holes in the stencils, and the locations of these holes match the locations where the PCB fabrication needs to be printed. When the printed circuit board is placed underneath the stencil while it is in use, solder paste leaks onto the PCB through a tiny hole that is fixed in place on the stencil. More solder paste is placed on the board PCB the less soldering paste is prevented on the stencil. Therefore, the condition of the stencils should be examined first whenever there is a printing process flaw.
PCB Stencil made of
- Stencil frame
- Mesh
- Sheet
- Glue
General requirements and principles
- High opening accuracy must be ensured by the exact position and specification, and the opening must strictly follow the designated opening procedure.
- Be very careful when extending the mesh, and pay close attention to the entrance range, which needs to be horizontal and centred.
- With the printing area on top, the mesh’s lower entrance must be either 0.01mm or 0.02mm broader than its higher opening, creating an inverted conical shape that will help solder paste be released from the mesh more effectively and shorten the time it takes to clean the stencil.
- The mesh wall must be smooth.
- SMT components typically have a stencil aperture specification and form that match the pad, and the aperture ratio is 1:1. SMT solder paste layers must be present in the data file needed to create the laser stencil.