The installation of in-house and purpose designed machines for producing polished stainless steel belts is paying off for Sandvik, as applications and demand for new types of plastic film continue to increase. Sandvik has met the needs of the film and photo market in two ways. First, a high-grade surface finish or “super finish” relies on the use of steel with low and controlled inclusion levels. Sandvik employs steel making techniques involving several remeltings of the steel using electro slag remelting and vacuum arc remelting practices. Second, Sandvik has designed and installed special polishing machines at its manufacturing plant at Sandvik Japan, capable of producing the highest quality, mirror finish belts. The Sandvik polished belt range has four austenitic stainless steel grades and two martensitic grades available in a range of belt thicknesses and widths for producing different types of plastic film. There are five different grades of polished belt available ranging from a standard surface specification for packaging films to the highest specification surface finish for LCD films. Inspection of polished belts is a stringent and demanding operation involving both automated equipment and close visual inspection. The Sandvik manufacturing process ensures that the specification limits are carefully controlled and checked, both during and after the polishing process.
