Abstract: A mould for manufacturing disc-like objects including at least two mould parts which are mutually movable between a closed position in which they bound a mould cavity, which mould cavity is connected to an injection conduit for admitting heated, plasticized plastic under pressure into said mould cavity, and an opened position in which a disc-like object can be removed. The mould also has a device for removing a central portion from a disc-like object to form a central hole present therein, which device comprises a cylindrical part which is movable in axial direction in the closed situation of the mould cavity. The mould has the feature that at least one of the two mould parts is tempered only in the middle zone of the mould cavity for tempering the inflowing plastic during the inflow thereof via the pressure line and thus during the filling of the mould cavity.

Abstract: An injection moulding unit includes at least two injection moulds for manufacturing disc-like objects. The injection moulds each further include two mould parts which are mutually displaceable between a closed position in which they bound a mould cavity and an opened position in which the disc-like object can be removed. The mould cavity is connected to a pressure line for carrying heated plastic into the mould cavity. A punching means is provided for punching a central hole through the disc-like object. The punching means includes a cylindrical part forming a portion of one of the mould parts and has a leading peripheral edge. The respective pressure lines of the injection moulds are branches of a feed line and together therewith form part of a collective multiple hot runner. The outlet zone of each feed line is configured to couple to an infeed of an injection bush. An outfeed of the injection bush debouches directly into the mould cavity.

Abstract: An injection mould for manufacturing plastic objects generally includes: two mould parts mutually movable between a closed position and an open position, which mould parts bound in closed position a mould cavity into which in the closed position heated plasticized plastic can be injected by means of supply means, wherein one flat end surface of the mould cavity carries a mechanical pattern, which pattern corresponds with the information for arranging on an information carrier to be manufactured, wherein at least a part of the surfaces is provided with a coating not containing TiN and which reduces a coefficient of friction of the relevant surface to a value which amounts to a maximum of 60% of the value obtainable a coating of TiN; wherein at least one of the cylindrical inner surface and the cylindrical outer surface is provided with the coating.