mouldmaking | Pallets
Austrian mouldmaker Haidlmair stretched its mould design know- how in the development of a new two-component PP/TPE pallet
Haidlmair gets a grip on TPE pallet project
Right: View of the moving half of the complex Interpallet mould in
Engel’s 3,200 tonne Duo moulding machine
Below: Image clearly shows the location of the 2mm thick TPE anti-slip elements on the pallet ribbing
Austrian mouldmaker Haidlmair worked closely with Norwegian logistics firm Interpallet to realise a new multi-component injection moulded polypropylene pallet that features integrated anti-slip zones on its upper and lower surfaces to improve load retention. PP pallets offer many advantages over traditional
wooden alternatives, according to logistics start-up company Interpallet. These include durability, mechani- cal performance, hygiene and moisture resistance. But the lower coefficient of friction of PP compared to wood has often forced logistics users to use load stability straps or opt for box-type pallet designs to eliminate the risk of load movement and spilling in transit or pallets slipping on lifting forks. This adds cost, time delays and additional labour input that ultimately reduces overall efficiency and productivity of the logistical system.
Helge Almestad, managing director of Interpallet, says the company determined that the key to the successful introduction of plastics pallets into the Scandinavian market would be the ability to produce a design
that at least matched the frictional coefficient of wood in both
wet and dry conditions. “For us the only solution in question was a
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pallet with local anti-slip strips or coatings made of injection mouldable TPE on both the product carrier side and the forklift side,” he says. Interpallet’s requirements were that the TPE should be soft and abrasion resistant over a temperature range from ambient down to -30 ° C and that it had to be firmly and permanently bonded to the structure of the pallet. The company also wanted to avoid any post treat- ment operations by using a two-component injection moulding process. “We discussed our concept drawings with several major machine manufacturers and tool makers, until we finally found the right partners in the Austrian companies Haidlmair and Engel,” says Almestad. “ Haidlmair impressed us with its already realised injection moulds for large containers and with its suggestions for transferring our pallet design in an economically viable production solution”. For Haidlmair, with its long background in produc-
tion of large moulds for the logistics industry, the basic design of the pallet mould was fairly straightforward. The grid pattern for the 1,200mm by 800mm by 150mm Euro pallet was optimised for the required 1,000kg payload using CAE simulation software and a PP grade with good low temperature impact resistance selected. A 10-nozzle hot runner system was designed to allow effective filling with the PP, which was a low MFI grade. The mould includes hydraulic cores on all four sides,
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