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

04.09.2023

It is almost time for the Fakuma 2023 trade fair. Trade visitors to Arburg’s stand, 3101 in Hall A3, will discover nine exciting exhibits together with all they need to know about the topics of sustainability, digitalisation and automation in the world of plastics. An electric Allrounder 720 A "Ultimate" will be demonstrating that high-quality injection moulding technology can be an alternative to thermoforming. The exhibit will use injection compression moulding to produce thin-walled IML cups that can be easily recycled after use.

Energy- and resource-saving alternative to thermoforming: An electric Allrounder 720 A "Ultimate" produces thin-walled IML cups at Fakuma 2023 using the injection compression moulding process. Photo: Arburg

• Powerful: Electric Allrounder "Ultimate"
• Energy-efficient: Injection compression moulding as an alternative to thermoforming
• Comprehensive: Arburg presents a great many sustainable, digital and automated solutions

The directly driven high-performance machine with a clamping force of 2,900 kN is equipped with a size 1300 injection unit that is specifically optimised for high performance.

Thanks to high-precision servo motors from Arburg's sister company AMKmotion, very high injection volume flows and injection speeds of up to 400 millimetres per second can be achieved.

IML cups only 0.37 millimetres thick

The recyclable IML round cups made of PP monomer material have a wall thickness of only 0.37 millimetres. Photo: Arburg

The exhibit uses a 4-cavity mould from Brink to produce thin-walled IML round cups from polypropylene (PP) using the injection compression moulding process. The flowpath/wall thickness ratio is 380:1. For process monitoring, the mould is equipped with six high-resolution inductive position measuring and embossing sensors. Four moulded parts, each weighing 10.8 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 10.8 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.

Further information about Arburg can be found at www.arburg.com