ALLROUNDER 720 A: Efficient injection compression moulding of IML thin-walled cups

An electric ALLROUNDER 720 A in the "Ultimate" performance variant demonstrates at NPE 2024 that high-quality injection moulding technology can be an alternative to thermoforming. The exhibit uses injection compression moulding to produce thin-walled IML cups that can be easily recycled after use.

IML cups only 0.37 millimetres thick

The exhibit uses a 4-cavity mould from Brink to produce thin-walled IML round cups from polypropylene (PP) using compression moulding at an injection pressure of just 23,000 psi (1,600 bar). For process monitoring, the mould is equipped with six high-resolution inductive position measuring and embossing sensors. Four moulded parts, each weighing 10.4 grams and with a wall thickness of only 0.37 millimetres, are produced in a cycle time of 3.95 seconds. The plastic has a biomass footprint and ISCC-certified. Also integrated into the production cell is a side-entry robot from Brink that inserts the labels, removes the finished cups and stacks them on a conveyor belt.

Resource-saving and recyclable

In this particularly resource-saving application for the packaging industry, special emphasis was placed on energy efficiency and on a part design that saves materials. Thanks to the all-electric packaging machine in combination with injection compression moulding, the energy footprint is improved by 20 per cent with a significant reduction in part weight from 13 to 10.4 grams. Meanwhile, the flowpath/wall thickness ratio is 380:1. Normally, this would require a very high level of injection pressure – at the expense of energy requirements and mould wear. This is why injection compression moulding is used for this application. Compared to classic injection moulding, this process requires significantly less injection pressure and it is possible to work with mould temperatures of 20 instead of 12 degrees Celsius. The special "Next Cycle IML" label can be completely separated from the PP of the cup during recycling, so that the product can be recycled by type after use. In contrast to thermoforming, no pre-produced foils are used and no stamping waste is produced

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