SMT stencil production and acceptance considerations
SMT stencil is a special mold for SMT processing. Its main function is to help the deposition of solder paste. The purpose is to transfer the exact amount of solder paste to the exact position on the empty PCB. SMT stencil plays an important role and affects the paste. The quality of the film processing. Therefore, there are strict standards for the production and acceptance of stencil. The following Xinda PCBA factory will introduce the SMT stencil production requirements and acceptance considerations for everyone.
First, SMT stencil production requirements:
1. According to the relevant documents and materials provided by the engineering department, the supplier is required to make a steel mesh.
2. The type of steel product to be marked, thickness, date of manufacture, etc.
3. the frame size of the stencil requires 550MM * 650MM 370MM * 470MM, etc., mainly based on the structure of the printing machine and product specifications.
4. the thickness of the stencil (scraping glue is generally 0.18MM-0.2MMM, scraping tin 0.1MM-0.15MM).
5. the opening mode of the stencil and the size of the opening (anti-tin beads generally open V-shaped, U-shaped, concave, etc., depending on the type of each component.)
6. the direction of the board and the placement machine should be unified.
Second, SMT stencil acceptance considerations:
1. Check if the way and size of the stencil opening meet the requirements.
2. Check if the thickness of the stencil meets the product requirements.
3. Check if the frame size of the stencil is correct.
4. Check if the marking of the stencil is complete.
5. Check if the flatness of the stencil mesh is level.
6. Check if the tension of the stencil is good.
7.Check if the position and quantity of the stencil opening are consistent with the GERBER file.
The quality of the SMT stencil determines whether the tin on the pad is uniform and full. It has a great influence on the reliability of the solder after reflow soldering after SMT components are mounted. Therefore, it is necessary to make a stencil according to requirements and accept it to ensure quality.