Melt push back process

First of all, the cavity is filled completely with melt [analogously compact - injection moulding] and then opens the overflow prior to the fluid injection. The fluid displaces the still liquid melt core directly back to the space in front of the screw of the injection moulding machine [IMM]. The pushed back material that is situated in front of the screw generates directly in the next cycle the outer skin of the following component. This prevents a semi-stable mixture of repeatedly reused material, e.g. recycling of residual materials from the overflow process.

By the special hot runner systems, developed by PME, the thermal and mechanical material reduction is stopped. Multi cavity applications share the same screw chamber.

 

If one uses gas as fluid, it is extremely difficult because of the missing volume control of the gas and the complex process balance. The PMEfluidtec water injection technology with integrated pressure-dependent control of the volume flow rate, regulates the respective cavity during the blow-out process of the melt.

High reproducibility, highest process ability, lowest material input as well as low energy costs make the melt push back process the favourite choice.

Suitability:
Typical application examples are roof rails, pipes, bigger handles but also very complex components like the Lasher wheelbarrow frame.

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