IML and decoration | Innovation
Right: Canada’s Emballages
IML Plastx won a Gold award
from IMDA for this IML sauce pack with
integrated spout and handle for O Sole Mio
high cavitation moulds. “Europe is probably more advanced in terms of challenging geom- etries and designs,” he says. “But in North America, to handle the volumes you need much bigger and more technically complex systems. So in some ways, the region has leap-frogged Europe.” StackTeck’s pilot cell for IML, now
in its third generation, gets regular usage. “We are very pleased that the level of activity meant it made sense for us to buy the equipment rather than have it on loan from equipment suppliers, like we did with earlier generations,” Robertson says. Since the company installed its first IML pilot cell in
2005 (which supported many of the earliest large volume IML projects in North America), StackTeck has worked jointly with ABB and CBW Automation for robotics, Husky and Netstal for injection machines, Machines Pagès for IML automation systems, as well as other leading IML automation providers, to create new cells. StackTeck president Randy Yakimishyn says IML
Below: IML pilot cell 6-axis robot at StackTeck’s technical centre in Canada showing the mandrel held at the label loading position
technology “offers tremendous added value for injection moulded parts. For two past projects, our customers have reported sales volume increases of 12% and 23%, following the introduction of a new IML package.” StackTeck is also claiming a success with the
combination of IML and its TRIM process for making thin-walled containers. TRIM stands for Thin Recess Injection Molding. TRIM tubs have walls made up of a series of vertical panels, with ultra thin panels alternating with less thin. The ultra-thin panels can account for between 50 and 90% of the part area (including the base and walls), enabling total part weight reductions of between 20 and 40%. Polypropylene tubs typically have L:T ratios (the ratio
of flow length to average wall thickness) of between 260:1 and 300:1. In TRIM parts, the thin panels can have L:T ratios as high as 520:1. The company has a long history in thin-walling. Robertson describes a 6-oz cup it designed several years ago where the walls were almost
completely comprised of the label, which completely filled the space
between the core and cavity except for three ribs running from the base to the rim. Weighing around 2g it was “ridiculously light” but was perhaps a step too far, he says, as there were no takers in the market. The next step was take a slightly less extreme IML
part comprising a rectangular tub with the label fully covered behind by melt. “The theory was, we take a part that is already near the limit of thin-walling, and we put in panels approximately 50% thinner still,” says Robertson. “We achieved over 20% lightweighting.” While Robertson says there was a lot of initial
interest, still no customers were prepared to bite the bullet. Then last year, that changed. StackTeck had already built a mould for a 64-oz round food bucket for a customer in Thailand, Srithai Superware. The design was already very thin, with an L:T of around 320:1, but the customer wanted it lighter. StackTeck presented its TRIM concept in a version with a 90/10 rib structure (90% ultrathin) that would provide an average L:T of 520:1 (min of 300, max of 600). “It worked out extreme- ly well. We only had to change the core components, so the cost of the modification was moderate,” he says.
Surface effects Another novel technology combination is IML and Trexel’s MuCell microcellular foaming technology, which can create the look of an embossed part from a flat mould surface. Originally developed by the technology company with packaging producer Paccor for use by Unilever in Europe, Trexel now has global marketing rights to the process, which it has called Mucell 3D IML. The technology creates the look of an embossed label on the package through partial entrapment of gas between the moulding and the label. The MuCell process uses nitrogen to create a cellular structure in the part. Under normal conditions, some of this gas migrates out after moulding. And in normal IML processes, where the label becomes an integral part of the moulding, it will migrate through the label as well. But it is possible to trap the gas between the part and the label in areas where the label does not adhere to
30 INJECTION WORLD | June 2014
www.injectionworld.com
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