Abstract: The invention is a compact disc manufacturing mold which permits the mold to be used to produce a variety of non-standard sizes and shapes. A replaceable flat cavity ring which fits between the conventional mold pieces encloses the outer boundary of the disc and has an inner shape which defines the non-standard disc shape. The cavity ring includes a cylindrical projection extending from its surface which is in contact with the face of the mold piece. The extension is inserted into a groove in the mold face and is locked into the mold by threaded plugs screwed through the cylindrical sides of the mold piece.

Abstract: The invention is a compact disc manufacturing mold which permits the mold to be used to produce a variety of non-standard sizes and shapes. A replaceable flat cavity ring which fits between the conventional mold pieces encloses the outer boundary of the disc and has an inner shape which defines the non-standard disc shape. The cavity ring includes a cylindrical projection extending from its surface which is in contact with the face of the mold piece. The extension is inserted into a groove in the mold face and is locked into the mold by threaded plugs screwed through the cylindrical sides of the mold piece.

Abstract: The apparatus is a hub bushing, called a gate insert, for an optical disc mold in which a thermally conductive but soft metal base structure is coated with a thin film physical vapor deposition or chemical vapor deposition coating which furnishes an extremely hard coating to protect the surfaces from wear. The base structure material of the gate insert is copper, aluminum, or a copper or aluminum based alloy, and typical materials used for the physical vapor deposition or chemical vapor deposition coating are titanium nitride, titanium carbide, or titanium carbonitride. Since the coating is only a few micrometers thick it has virtually no affect on the excellent thermal conductivity of the base structure, and the high thermal conductivity of the gate insert prevents quality degradation in the optical discs produced by the mold because the mold surfaces are prevented from having too great a difference in temperatures.