title: Optical inspection of punches: flat surfaces.
abstract: Optical inspection techniques for estimation of surface roughness and surface quality of flat punches, which are used in the pharmaceutical industry for tablet compression, were studied. It was observed that a simple specular reflection technique is useful for surface roughness assessment of flat punches. A diffractive element based sensor was used for the surface quality detection, such as mirror property or flatness, with the aid of image information of a test pattern. It was observed that a new punch may have a poorer surface quality than a used one.
authors.affiliation: Department of Physics, University of Joensuu, Joensuu, Finland.
authors.forename: V
authors.initials: V
authors.lastname: Hyvärinen
authors.forename: K
authors.initials: K
authors.lastname: Peiponen
authors.forename: R
authors.initials: R
authors.lastname: Silvennoinen
authors.forename: P
authors.initials: P
authors.lastname: Raatikainen
authors.forename: P
authors.initials: P
authors.lastname: Paronen
authors.forename: T
authors.initials: T
authors.lastname: Niskanen
mesh_terms: D055095:Optics and Photonics / Q000295:instrumentation*; D013607:Tablets; D013678:Technology, Pharmaceutical / Q000295:instrumentation*
chemical_list: D013607:Tablets