EMS Electronics Factory PCBA Processing Solder Paste Process--Ultra-practical SMT Stencil Opening Design Optimization Guide
Oct 16, 2021
No-wash opening design
SMT solder paste printing stencil (stencil) is also called SMT stencil, SMT screen, SMT stencil. It is used to quantify solder paste or patch red glue, and is the key to ensuring the quality of printed solder paste/ patch red glue Tooling.
For the electronic EMS assembly industry, SMT assembly is a fairly mature process technology, but maturity does not mean that there will be no defects. On the contrary, with the further miniaturization of electronic component packaging, process problems become more difficult to control.
According to authoritative statistics, the most important and critical process in the SMT process should be the solder paste printing process. Almost 70% of soldering defects are caused by poor solder paste printing.
The solder paste printing process is related to the success or failure of the SMT assembly quality, and the design and manufacture of the stencil is a key factor in the quality of the solder paste printing. Proper design can get a good solder paste printing result, otherwise it will cause the process quality to be unstable. , Defects are difficult to control. The following content will list some common SMT solder paste stencil opening optimization designs for your reference.
The thickness of the template and the size of the opening, the shape of the opening, the state of the inner wall of the opening, etc. determine the amount of solder paste printed, so the quality of the template directly affects the amount of solder paste printed. With the development of SMT to high-density and ultra-high-density assembly, template design becomes more important.
Template design is one of the important contents of SMT manufacturability design!
SMT steel mesh template design content:
Template thickness
Template opening design
Selection of template processing method
Step/release template design
Hybrid technology: through-hole/surface-mount template design
No-wash opening design
Template Design of Ball Grid Array (PBGA)
Template design of ball grid array (CBGA)
Template design of micro BGA/chip-level packaging (CSP)
Hybrid technology: surface mount/flip chip template design
Glue template opening design