PRODUCTION - PLASTIC

Injection moulding:

Injection moulding is a primary forming process that is mainly used in plastic processing. This process enables directly usable shaped parts to be economically produced in large quantities.  To achieve this, an injection moulding machine is used to plasticise the respective plastic in an injection unit, after which it is injected into an injection mould. The mould's cavity determines the shape and surface texture of the finished part.

Injection moulding can be used to produce highly accurate objects, such as for precision engineering and / or mass-produced items, within a short period. The component's surface can be selected almost freely. Smooth surfaces for visual applications, grainy textures to facilitate contact, patterns and engravings can all be created.

The injection moulding process is economically appropriate (almost only) for larger quantities. The costs of the mould account for a major proportion of the necessary investment. Consequently, even in the case of simple moulds, at least a few thousand units must be produced for it to be economically feasible. On the other hand, the moulds can then be used to make up to a few million parts.

Injection mould:

An injection mould is a mould consisting of several subassemblies and various individual parts, primarily steel, and is used to manufacture large volumes of plastic parts. An injection mould can have one or two separation planes and several cavities with mould cores per separation plane, thereby allowing several plastic parts to be produced simultaneously in one mould. The cylinder of the injection moulding machine injects the plastic into the mould cavities at high pressure through the feed channels, with the result that the air escapes. Special venting channels in the mould part result in cooling via a cooling cycle until the parts can be ejected from the mould.

The duration of the cycle (time between two mould ejection operations) depends on the workpiece size and the cooling duration. Ejection from the mould is performed by ejectors, and ejection robots can be used to remove the moulded parts. The service life of the injection mould depends on various parameters of the injection cycle, such as temperature and temperature differences, or the injection pressure.

A distinction is made between, among other things, cold runner moulds and hot runner moulds. In the case of cold runner systems, the plastic hardens in the gate and is separated after the moulded part has been ejected. Hot runner systems can have needle closure systems, with which the injection nozzle is closed by a closing needle immediately after the dwell pressure.

Mould making is a highly specialised field of mechanical engineering that deals with, among other things, the manufacture of injection moulding machines.

"(Source: Wikipedia)"