subject: Mould Of Container Cap [print this page] In accordance with the present invention there is provided a cap mould for use on an injection moulding machine, comprising a pair of mould parts which are axially movable towards and away from each other, and which in their closed position define a mould cavity, the said parts having co-operating locating surfaces which determine the relative radial positions of the mould parts, and wherein the locating surface on one of the cap mould parts is adjustable, in the radial direction, relative to the surfaces of the mould ports which border the mould cavity
In the past, in the moulding of very thin walled containers especially those with circular cross-section and near-cylindrical or frusto-conical shape, great difficulty has been encountered in maintaining the radial wall thickness. Even when the cap mould parts are made initially with sufficiently high accuracy to obtain a uniform wall thickness, it is the common experience that after a period of use, the wall thickness will vary and will be no longer uniform. Where very thin wall thicknesses are involved, this may lead to inadequate properties of the finished container.
By means of a cap mould of the type described, it has been found possible to mould consistently thin walled containers, the wall thickness being less than that possible with conventional forms of mould. For example, it has been found possible to cap mould consistently containers having a wall thickness of approximately 0.013 inches and; by maintenance of the moulding machine by adjustment of the segments of the locating ring 23, such wall thicknesses have been maintained.
