Abstract:
Bei dem Verfahren zur Fertigung von Brillengläsern (32) werden in der Rezept- bzw. Individual-Rezeptfertigung Kunststoffrohlinge (1), in Form von flachen, runden Scheiben benutzt. Die verwendeten Kunststoffrohlinge (1) werden am äusseren Rand gespannt und danach die gewünschte endgültige Oberflächengeometrie und Oberflächenqualität der Linsenvorderseite (19) und Linsenrückseite (27) durch Zerspanen mit Fräs- und/oder Drehwerkzeugen sowie durch Feinschleifen und ggf. Polieren hergestellt. Bei der Bearbeitung bleibt ein ringförmiger Bereich (30) am äusseren Umfang des Werkstücks (16) in grösserer Dicke (33) erhalten. Dieser ringförmige Bereich (30) dient bei allen Bearbeitungs- und Transportvorgängen zum Spannen oder Ablegen des Werkstücks (16). Ausserdem stützt und stabilisiert er das eigentliche Brillenglas (32) für die weitere Bearbeitung. An dem ringförmigen Bereich (30) werden Formgebungen angebracht, welche zur Identifikation der Bearbeitungsachsen dienen. An dem eigentlichen Brillenglas (32) werden feine Markierungen zur Kennzeichnung des erzeugten Brillenglases (32) angebracht. Anschliessend wird das Brillenglas (32) von dem ringförmigen Bereich (30) abgetrennt.
Abstract:
For manufacturing ophthalmic lenses and other optical form bodies made of plastic material, plastic form parts are used which are made by non-cutting shaping and are then further worked by mechanical production steps. Said plastic form parts are circular blanks (1) made of two different plastic materials which are firmly joined to each other. Thereby, an interior lens element (2) that consists of a high-quality material is concentrically surrounded by a ring fixture (3) which consists of a low priced material. Either surface of the lens element (2) may feature any given geometry. During mechanical working, the ring fixture (3) is used for mounting as well as for depositing and, in addition, for stabilizing the workpiece (9). For this reason it is partially maintained throughout the mechanical working and is cut off at the end only.
Abstract:
A raster cutting apparatus and method for producing accurately formed, aspheric ophthalmic lenses having a good quality surface finish. The accurate form and good surface finish are obtained by using a substantially spherically shaped cutting tool having a large radius. The methods include utilizing a cutting path which provides substantially constant cutting-force, such as a constant surface-cutting-speed raster pattern.
Abstract:
For manufacturing ophthalmic lenses and other optical form bodies made of plastic material, plastic form parts are used which are made by non-cutting shaping and are then further worked by mechanical production steps. Said plastic form parts are circular blanks (1) made of two different plastic materials which are firmly joined to each other. Thereby, an interior lens element (2) that consists of a high-quality material is concentrically surrounded by a ring fixture (3) which consists of a low priced material. Either surface of the lens element (2) may feature any given geometry. During mechanical working, the ring fixture (3) is used for mounting as well as for depositing and, in addition, for stabilizing the workpiece (9). For this reason it is partially maintained throughout the mechanical working and is cut off at the end only.