Teldec Telefunken-decca Schallplatten Gmbh

Teldec Schallplatten Gmbh

Klaus Roschmann

Herbert Knothe

Horst Redlich

Emanuel Pfeil

Process for producing a cutting base

Process for manufacturing a record carrier having a cuttable copper layer, wherein a copper layer is precipitated onto a substrate in an electrochemical bath and a desired Vickers hardness in the precipitated copper layer is obtained by controlling the concentration of brightener additives. The copper layer is precipitated in a recrystallizable phase, and the recording is cut while the copper layer is in its recrystallizable phase.

Method for producing a record carrier

In an apparatus for forming a groove which is modulated to present an information track in a signal record carrier having a copper surface portion by cutting such groove into the copper surface portion by means of a cutting stylus, the stylus is formed to present, during cutting, a rake angle of between 10.degree. and 20.degree., and the copper constituting the surface portion into which the groove is cut has a Vickers hardness of between 110 and 300, and preferably between 120-220.

Mechanical record cutting method

A process for producing and operating an electroplating bath in which there appears NH.sub.4.sup.+ ions which impair the quality of the bath comprising adding salts of a hexanitrocobaltate-III complex to the bath to bring about precipitation of the NH.sub.4.sup.+ ions.

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Schulp, Germany

Klaus Roschmann