What is stencil in SMT production?

Stencil, also known as solder paste stencil, is one of the key components in the SMT production process. It is made of high-precision special stainless steel plate, and through precise laser cutting or electrochemical etching technology, specific hole patterns are created on the steel plate, which correspond to the positions of the components that need to be welded on the circuit board.

In the SMT production process, the main task of the stencil is to accurately print solder paste onto the positions of the components that need to be soldered on the PCB. This process is also known as solder paste printing.

In the process of solder paste printing, first place the solder paste on top of the stencil, and then use a scraper to evenly scrape the solder paste across the stencil, so that the solder paste can be accurately printed onto the PCB through the holes on the stencil. Then, the electronic components are precisely mounted onto the printed solder paste positions using a mounting machine, and finally soldered onto the PCB through reflow soldering.

Therefore, stencil plays a crucial role in SMT production. It not only ensures that the solder paste is accurately printed to the position that needs to be welded, but also controls the amount of solder paste by changing the size and shape of the holes on the steel mesh, thereby ensuring the welding quality.

The function of stencil

• Ensure welding quality, By precisely controlling the amount of solder paste and printing position, the stencil can ensure welding quality. If there is no stencil, the solder paste may be printed inaccurately, leading to a decrease in welding quality.
• Improve production efficiency, Stencil can achieve fast and accurate printing of solder paste, greatly improving production efficiency. Without stencil, it needs to manually apply solder paste, which is not only time-consuming but also cannot guarantee accuracy.
• Cost saving, Stencil can effectively control the amount of solder paste used, avoid waste, and thus save costs.
• Improving product quality stability, Stencil enables controllable printing volume and position of solder paste, greatly enhancing the stability of product quality. In mass production, stencil can ensure that the welding quality of each product is consistent.
• Flexible and applicable: Stencil can customize different hole patterns according to different PCB designs and component requirements, with strong flexibility.