With the development of SMT, the demand for stencils will increase, and the steel mesh will follow. Affected by material costs and ease of fabrication, the original stencils were made of iron/copper sheets, but because of the rust, stainless steel stencils replaced them, which is now the SMT Stencil. According to the manufacturing process of SMT steel mesh, it can be divided into: laser template, electropolishing template, electroforming template, ladder template, bonding template, nickel plating template, etching template.
SMT laser steel mesh is the most commonly used template in the SMT steel mesh industry. Its characteristics are:
1. Directly adopt data file production, which reduces the production error link;
2, SMT laser steel mesh opening position accuracy is extremely high, the whole process error ≤ ± 4μm;
3, SMT laser steel mesh opening has a geometric shape, which is conducive to the printing and molding of solder paste.
The following materials are required to make an SMT laser stencil:
1, PCB
2, film
3, the data file
Material requirements:
1. PCB: The version is correct, without deformation, damage or breakage;
2, film: is the SMD layer and silk screen layer, indicating the front and back, to ensure that no cold and heat, no creases;
3, data files: There are a variety of CAD data formats: GERBER, HPGL, *.JOB, *.PCB, *.GWK, *.CWK, *.PWK, *.DXF, *.PDF; and the following software design data : PAD2000, GCCAM4.14, POWERPCB, PROTEL, AUTOCADR14 (2000), V2001, CAW350W, V2001 CLIENT98. When the data is too large, it should be compressed and transmitted. Any compression format such as *.ZIP, *.ARJ, *.LZH can be used; the data must contain SMTsolderpastelayer (containing FiducialMark data and PCB shape data), and must also contain character layer data for checking. The front and back of the data, component categories, etc.
SMT laser steel mesh post processing
Etching and electroforming stencils are generally not post-treated. Since laser slag will cause metal slag to adhere to the walls and openings, surface grinding is generally performed; of course, sanding is not just to remove slag (burr). At the same time, it also roughens the surface of the steel sheet, increases the surface friction, and promotes the rolling effect of the solder paste to achieve a good tinning effect; if necessary, it can also choose "electropolishing" to completely remove the slag (burr) Improve the hole wall.