Smt steel mesh anti-tin beads is a special process for the production and processing of steel mesh. To put it simply, it is the special treatment of the shape of the opening of the steel mesh.
The function is to control the amount of tin under the SMT stencil. When the tin beads are easy to appear, the stencil reduces the size or shape of the window, so that the solder paste flows to the place where there is no tin. Thereby achieving the purpose of not easily appearing tin beads.
Then do you doubt it? Why does Jiali Chuang Laser Steel Network (1800 units per day) need anti-tin beads, and some SMT steel nets do not need anti-tin beads, can they be used?
This is because the solder paste used in the patch factory is different, and the thickness of the steel mesh is different, and the design of the pad of the circuit board itself is different, so these problems need to change the amount of tin from the steel mesh. According to industry standards, the 0402 component guarantees an internal distance of 0.4 and does not require anti-tin beads. And the 0603 components, the internal distance is guaranteed between 0.6-0.8, can be prevented from seeing the thickness. 0805 Inside distance guarantee between 0.9-1.1, anti-tin beads are required.
The shape of the open anti-tin beads can be selected according to different customers. Of course, some need to be specially designed according to the different processes of the SMT patch factory. The anti-tin beads of the large pad are divided into grids to prevent the amount of tin on the components from being too large and the components to be offset. The anti-tin beads of the IC reduce the width of the components and prevent the tin from being connected. For special components, customers need to provide stencil design. After all, SMT stencil factory is not a patch factory, can not see the real components, can only be designed according to the conventional scheme. Need special, you need to provide design solutions with customers, you can open a quality steel mesh.