GB698209A - A method for the production of pressing-tools - Google Patents

Abstract

698,209. Making dies. HUSQVARNA VAPENFABRIKS AKTIEBOLAGET. April 27, 1951 [April 29, 1950], No. 9960/51. Class 83 (ii). A method of making a pressing tool or die comprises giving one side of a model a coating of an easily fusible metal such as zinc, removing the coating, electrically depositing on the cavity left by the model a layer of a metal such as copper having a higher melting point than the coating and then removing the copper shell, filling the cavities on the back thereof with a metal and finally using the shell to compact a mass of iron powder which is then sintered to form the tool. A plastic comb 1 is glued to a suitably curved metal plate 2 and sprayed with zinc until a layer 3 of between <SP>5</SP>/ 64 and # inch thick is obtained. This layer is removed, given a coat of insulating lacquer 4 on the side that was remote from the comb and on the other side is electro deposited a copper layer 5 of between 0.08 and 0.10 inch thick, after which the lacquer and the zinc are removed, the zinc, for example, being dissolved in hydrochloric acid. The copper duplicate 6 has the cavities filled in with tin 7 to increase rigidity and is used to form the bottom of a die 8 for compacting a mass of iron powder 10 which, after compacting and sintering, forms a press tool for the manufacture of plastic combs. In modifications, the first metal layer 3 may be deposited on the original by vaporizing the metal in a vacuum chamber, by cathodic atomization or chemically, as by silver plating, the thickness of the layer being increased by electroplating if necessary. If the original model is of low melting-point metal instead of plastic, the layer 3 could be obtained entirely by the electrodeposition of a higher melting- point metal, after which the model is removed by melting it out.