Fluid Injection Technology - process comparison

New designs and an otherwise not attainable quality of the components are only possible by the removal of not required material from the structural core and the holding pressure from inside almost without any pressure loss by the fluid. Moreover, competitiveness is drastically improved by a massive cost reduction [saving material and cycle time]. Particularly one should not disregard the environmental concerns. With the fluid process, especially the water-based one in combination with the PME know-how, it is possible to reach a reduction of the CO2 emission by up to 80%.

The essential question is: gas versus water

In principle, these two primary processes have their specific area of application which is defined mainly by the component requirements. In the transition of the process selection, the total costs and the expected quantity decides in each individual case or even pragmatically which process equipment is already available.

There is a tendency for the usage of gas which is always preferred, when shrinkage shall be compensated, melt accumulations are not avoidable, channel cross sections are too small as well as the water cannot be removed from the component or when the size of the injector is decisive.

Water, however, is automatically used when the crosscuts and the channel length get too big in dependence of the material for the gas injection technology and when a smooth and closed surface is demanded e.g. in sanitary areas. The residual wall thickness generally plays a central role besides the low warpage. Economically seen, the considerably shorter cycle times and the non-incurred fluid costs by using water are the main focus.For large quantities this can lead to a reduction of the investment costs by up to 50% [halving of the production lines due to the increase in efficiency of each line].

For innovative new products, the already known standard procedures of the fluid injection are increasingly not sufficient enough. A greater number of special processes is therefore available, e.g the Combined Injection Technology (CIT).

For this process, water and gas injection is combined in one component. Areas with bigger crosscuts [e.g. handles] are demoulded with WIT and for the shrinkage compensation at the ribs, gas is used simultaneously. [At PME both can be combined in one controller and one formulation]. Typical applications are, for example, casings with rear ribs and handle areas, door pockets and carriers for motorbikes and scooters.

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