This is an alumina ceramic sheet requiring mirror finishing. Typically, polishing alumina ceramics involves rough grinding with an iron disc followed by polishing with a white cloth, but this method is extremely slow—often taking 30–40 minutes with the white cloth to achieve the desired mirror surface. This is unacceptable for batch processing. Alternatively, there is another method: after rough grinding with an iron disc, directly using a tin disc for mirror polishing. However, this approach also has drawbacks, primarily the high processing cost of tin discs, making it difficult to achieve mass production.
Generally, processing alumina ceramic sheets presents certain difficulties. First, alumina itself has high hardness, making it challenging to grind to precise dimensions. Second, the surface of alumina ceramic tends to absorb light, making it difficult to achieve a mirror finish with ordinary polishing methods. These factors significantly increase the difficulty of polishing alumina ceramics, but our company has successfully resolved this issue.
