In the SMT process, stencil production is an indispensable step, and it also plays a vital role, because it determines whether the tin on each pad is uniform and full, which affects the reflow of SMT components after mounting Welding reliability after welding.

Generally speaking, it is necessary to carefully analyze the characteristics of each PCB to develop steel mesh. For circuit boards with high-precision quality requirements, laser steel mesh must be used, and SMT engineers are required to confirm the process flow, and adjust the aperture of the opening appropriately to ensure Tin effect. However, there are some things to pay attention to when making steel mesh. The following Sanjing will take you to understand:

①ME requires the supplier to make steel mesh according to the relevant documents and materials provided by the engineering department.

②The frame size requirements of the steel mesh, such as 550mm*650mm, 370mm*470mm, are mainly determined according to the structure of the printing machine and the specifications of the product.

③The markings on the steel net, such as product model, thickness, production date, etc.

④The thickness of the steel mesh is generally 0.18mm~0.2mm for squeegee, and 0.1mm~0.15mm for tin squeegee.

⑤ The opening method and size of the steel mesh, the anti-tin ball is generally V-shaped, U-shaped and concave, etc., depending on the component type.

⑥ The direction of the board and the placement machine should be unified.

By the way, here is the precautions for the acceptance of the steel mesh of the SMT chip processing plant:

①Check whether the method, size and thickness of the steel mesh opening meet the requirements; ②Check whether the frame size and marking of the steel mesh are correct; ③Check whether the flatness and tension of the steel mesh are good; ④Check whether the position and quantity of the steel mesh opening are consistent with The Gerber files are consistent.

The above content is about the precautions when making SMT steel mesh, I hope it can be helpful to everyone!