INNOVATION | MEDICAL
Below: A model in
Sumitomo (SHI) Demag’s Super High Response machine range
and they see synergies of working together and cooperating to develop their businesses. MHT will bring in its leading expertise for BCT injection moulds and PET hot runners, while Kebo will bring in its expertise for medical injection moulds and hot runner solutions. Both companies will expand their businesses by providing comprehensive BCT solutions to their customers. Kebo and MHT can offer reliable system solutions “for the complete BCT product portfolio like test tubes, caps, rubber plugs, tube holders, luer adapters, needle hubs and protective caps,” says Ralf Berthold, Head of Projects at Kebo. Sipa, the Italian PET container machinery and mould maker, has developed a special cold-half core-centering technology for BCTs that makes it possible to adjust the core alignment from the front face of the tooling’s cold half, in contrast to competing solutions that require access to the back of the core plate. Sipa’s patent pending development makes any adjustment easier and faster to carry out during production. The new injection mould tooling solution, specifically for medical applications, encompasses applications from wide cell culture containers to deep and narrow BCTs. According to the company, production of high-quality BCTs requires that the wall thickness around the circumference is within very tight tolerances. The company says that “while such criteria also apply to more common PET products like bottle preforms, consistently high performance over long-term production is more difficult to ensure with BCTs”. This is because BCTs have a diameter much smaller than regular preforms, and the various components of the mould also have reduced dimensions. For example, the cores for a BCT mould have a small diameter and hence less stiffness than preform cores. “As a result, they are more likely to flex under the pressure of the PET melt if the wave front during injection is not perfectly symmetrical,” says Sipa. Injection pres- sures used in BCT moulding need to be higher than in preform production, due to the higher length and thickness ratios of the BCTs. This puts
IMAGE: SUMITOMO (SHI) DEMAG
the mould components under greater stress and increases the potential for deflection of the cores. The cold-half core-centering technology from
Sipa makes it easier to fine-tune the positions of the cores, correcting the slightest deviation from the set value. The processor can make adjustments to the mould while it is still in the machine by accessing the front face, moving half of the mould. Competing operations that require access to the back of the mould also require that at least part of the mould be taken out of the injection moulding machine, disassembled, adjusted, reassembled, and then refitted to the machine. Sumitomo (SHI) Demag’s North American
debut of its Super High Response (SHR) injection machine model at this year’s MD&M West show involved moulding 48 mm long, 255 g carbon- black enhanced electrically conductive pipette tips for capacitive liquid level sensing in a 64-cavity tool in a 6 s cycle time. The SE130EV-A-SHR model, part of the com-
pany’s SE-EV-A all-electric product line, features increased acceleration/deceleration capabilities from the injection unit and increased filling speed from the ultra-high-pressure screw, which offers a 30% increase in maximum injection pressure compared to the standard specification. The unit delivers a maximum injection speed of 1,000 mm, where 100% shot weight can be injected in 0.1 s. The SE130EV-A-SHR model also features a high-precision clamp motion control and a multi-toggle clamp force control offered in a high-cycle mode in which filling begins during clamping, for improved cycle time, or a gas-release mode in which filling begins during low-pressure clamping for improved part quality, says Bob Brady, North America Business Development Manager. The medical application demonstration was designed to showcase the machine’s capabili- ties for thin-wall high precision applications. Brady also says that clients making products for the medical industry are increasingly activating the company’s Flow Front Control (FFC) technology in its machines to prevent the production of flash and short shots that can occur in different cavities of a multi-cavity tool. FFC can be programmed to pause the injection stroke for a few milliseconds, giving any air trapped inside a mould cavity the chance to be evacuated, rather than
burning the flow front of material entering a mould cavity. The milliseconds used by FFC to achieve more uniform filling in each cavity
46 INJECTION WORLD | September 2023
www.injectionworld.com
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