Quality inspection of metal surfaces by diffractive optical element-based glossmeter

Planar, convex and concave metal surfaces were produced by utilizing finishing processes that are exploited in the production of tools for plastics injection molding. A novel glossmeter, the so-called diffractive optical element-based glossmeter (DOG), was used for the inspection of the gloss of the surfaces. The Society of the Plastics Industry (SPI) A1 standard, which has the lowest surface roughness of such standards, served as a reference for the success of the finishing process. The results show that by using DOG we can gain local microscopic and macroscopic information on the gloss and its variation. The DOG is sufficiently sensitive to detect small gloss variation as well as the texture of the surface, e.g. anisotropy in surface marks. Some of the surfaces in this study have a higher surface quality than the A1 surface.