The construction of the presses for injection moulding began in 1923 in Germany with manual models. Today, injection moulding is one of the most widely used technologies for the processing of plastics and mostly in the aerospace and automotive industries where plastic articles using this technology are produced. In addition to this, we can mention applications in the field of furnishing, professional and consumer electronics, pottery. The injection moulding process consists of various phases:
- Design. The product has a precise shape, therefore is initially designed by a designer or an industrial engineer; then, technical solutions, mathematics 3D and related construction drawings are developed.
- Prototyping. A manufacturer of moulds makes the custom-made mould, generally in steel or aluminium, considering the characteristics of the product itself and the properties of the machinery for injection moulding.
- Injection. The mould is inserted into the injection press and it is locked by the moulding machine; the plastic granule material is inserted in the injection press moulding machine; it is heated until it reaches the liquid form and is injected into the mould.
- Cooling and extraction. Once reached the solid form, the extractors push the cooled product out of the press as a finished product, completing the process.
- Quality control. In order to grant continuity in customer satisfaction, activities for the control of the manufacturing process, such as the monitoring of scraps, suppliers and others, are necessary.
Gas co-injection: one type of injection moulding
The gas co-injection is a type of injection moulding that can be used with all major types of amorphous and semi crystalline thermoplastic materials that bear different thicknesses, depending on their characteristics. Particularly, gas assisted injection moulding is a process that involves the injection of an inert gas inside a mould and then inside the molten mass through nozzles or needles; then, a bubble connected to the point of injection of the gas, which pushes the plastic material until the complete filling of the mould cavity is formed. The pressure on the gas is maintained until reaching the extraction temperature of the workpiece that is compressed against the walls of the mould. The opening of the mould and the extraction of the finished product take place at the end of this process, along with the decompression of the bubble. This technology consents the use of thermoplastic polymers in areas of application related to the production of special articles, for example those shapes with complex geometry or carrying very small dimensions; being areas usually reserved to the application of other materials, the co-injection of gas exceeds in this manner the limits of traditional injection moulding.
The advantages of the injection moulding of plastics
Injection moulding provides some advantages for the plastic processing, among which:
- This is a quick process, both from the production and marketing point of view, due to the collaboration with specialized partners in equipments that reduce delivery times.
- It facilitates high volume production while maintaining low operating costs.
- It grants the production of plastic articles in different colours and materials.
- The final product, after the process is concluded, has little need of finishes.
The highest achievement Fisem holds in injection moulding arises from its experience and competence, and to its technicians that are reachable to assess projects and building solutions to foster customer’s success.