It seems there ain't no mountain high enough to miss out on Sumitomo (SHI) Demag's injection moulding expertise, as the plastics processing giant plays a crucial role in producing high-performance ski boots.
Sumitomo
Ever since the first winter holiday 150 years ago, ski boot technology has been evolving and for Plastor SA, which produces component parts and bindings for the Salomon and Atomic ski boot ranges, precision is paramount.
Two decades of performance
The Romanian manufacturer counts on the technological prowess of Sumitomo (SHI) Demag and a fleet of injection moulding systems to maintain the high performance characteristics and biomechanics of the leading downhill ski boot brands.
For over two decades Plastor has collaborated with the French-based sports manufacturer Salomon and with Atomic since the turn of the 21st Century. Starting with just one injection moulding machine from Sumitomo (SHI) Demag in 1993, the Romanian production facility now has over 10 of their hydraulic systems - with clamping forces of between 1,000 and 4,200 kN - in
operation. Reliably producing components for the sporty alpine boots, Plastor more recently enhanced its plastic moulding capabilities, investing in a fully-electric IntElect 100-430 machine.
As well as favouring the lower energy consumption of its latest IntElect installation, Plastor’s Managing Director Ion Sereş was drawn towards the machine’s high speed and precision, and ability to produce multiple components for inherently complex products.
"When producing components for high performance ski boots, it is necessary to have simultaneous movement of moulds and core pulling," Seres said.
"These plasticising units are suitable for processing a wide range of thermoplastics and create a high quality melt. For instance, we get excellent results when we work with transparent and translucent TPUs coloured with liquid dyes."
He continued: "The machines are also characterised by a highly precise repeatability. The five-point twin toggle system makes for highly precise tool movements. Furthermore, the NC4 and NC5 machine control systems are very user-friendly, as the parameters for the detail controls are grouped."
Maintaining stability
Aside from developing and moulding the end products, Plastor also undertakes the surface decoration, employing techniques such as screen and pad printing and hot stamping.
Dave Raine, Technical Sales Manager at Sumitomo (SHI) Demag, explained: "Part stability is key in ensuring consistent transfer of the decoration onto the moulded part, whether it be pad printed or hot foiled. Achieving and maintaining a consistent stable process on the moulding machine is essential when employing post moulding decorative processes."
The complex process involves moulding small insert pieces from TPE, which must pass high precision quality tests. They are then reworked and inserted into bigger 2-component or 3-component parts made of translucent TPU in larger injection moulds. Production is semi-automated on moulds with two or four cavities; fully automated on others, achieving cycle times of less than 50 seconds.
What’s more, the IntElect machine is equipped with a dust extractor and a gravimetric dosing device, which can dose up to four different components.
Sumitomo
"The general aesthetics of ski boots has become an important consideration in design. Even and consistent dispersion of the complex translucent colorants is essential," said Raine. "Another issue with foil and printed decoration processes is contamination of the surface. Any imperfections or contaminants on the moulding will be highlighted on the decorated area. Dust particles under the foil show up as uneven or incomplete printing, and compromise the visual impact, which to some customers, can be just as important as the boots’ technical performance!"
Lower noise emissions are another feature of the all-electric machine. Seres noted: "We also benefit from the many opportunities for fine adjustments, i.e. during opening and closing of the mould, the ejection movement or during venting of the mould."
In addition to ski boots, Plastor is one of the leading suppliers of plastic components for the automotive and electronics sectors, as well as household appliances, sports and gardening equipment. The team of 750 employees also produce tools for the polymer processing industry - which is quite a different product portfolio to when they were founded a century ago, manufacturing hairpins and combs from natural raw materials.