Producing a cap
Granules and, if being used, masterbatch (coloured granules) are mixed in a hopper. A reciprocating screw is then used to feed the plastic, while being heated, forwards in the injector. The plastic is then injected into the tool, which is fitted with a large heater, and the molten plastic is routed via channels to the appropriate mould cavities via nozzles that keep the plastic hot. The plastic is then injected into the cavity via the intake under extremely high pressure, which requires immense clamping force to keep the moulding tool closed.
We now have an injection-moulded component, that is, a cap. The plastic then needs cooling so that the component retains its shape. The cap is allowed to rest while cooling until it has solidified. After cooling, the moulding tool is opened and the moving half of the tool is parted from the fixed half (the latter contains the nozzles). The cap remains in the moving half. Now the threaded core, which shapes the thread, begins to rotate and a stop prevents the cap from rotating together with the threaded core. The cap is then knocked out by a puller ring, the moulding section for the bottom of the cap, and falls onto a conveyor belt for transfer to the transport packaging section, such as for boxing up.