One: What is electropolishing
Electropolishing is the anodic etching of an object under specific conditions.
Second, the purpose
This process is intended to improve the microscopic geometry of the metal surface and reduce the micro-roughness of the metal surface.
Third, the principle
Electropolishing uses the principle of tip discharge.
Fourth, steel mesh electropolishing process
The stencil electropolishing process is an electrolysis process. The electropolishing tank is an electrolyzer. The stencil is fixed at the anode and immersed in an electropolishing solution with a high current. At this time, a thick mucous membrane having a high electrical resistivity is formed on the surface of the steel mesh, and the thickness of the microscopically convex portion of the surface of the mucosa is small, and the thickness is large at the microscopic concave portion. Therefore, the microscopic distribution of the current density is also The unevenness, coupled with the tip effect of the current, makes the protruding portion have a high current density and dissolves quickly, while the concave portion has a low current density and dissolves slowly, so that the size of the protruding portion is reduced rapidly. The size of the concave portion is reduced very slowly, so that the flatness is smoothed.
Five: the advantages of steel mesh electropolishing
Laser-cut stencils are characterized by the high concentration of laser energy, which is formed by perforating high-energy lasers to form openings. This causes the laser stencil to have metal slag at the edge of the opening, and the edge of the hole wall is not smooth and straight, which makes it difficult to print the solder paste. In order to improve this shortcoming of the laser stencil, it is now achieved by electropolishing.
After the laser template is electropolished, the slag and burrs in the pore walls are removed or improved in the solution, which improves the tin-carrying ability of the template.
Sixth, the risk of laser template electropolishing
Because of the characteristics of electropolishing, the wall of the laser template is smooth after electropolishing, but at the same time, the opening size becomes larger and the thickness is thinned. This poses a risk of insufficient solder paste. So laser template polishing must master a degree! (I said that the improvement is the reason. If the polishing is completely polished, the angle will become a rounded corner and the right-angled edge will become an arc-shaped edge.)