Update | thin wall GWK looks to CO2 for better quality
German mould temperature control specialist GWK has developed a variotherm (heat-cool) moulding technol- ogy suitable for production of demanding thin wall parts that uses CO2 in place of water to offer claimed savings in energy use and cycle time. CO2 has been used in the
past as a plastics cooling medium, particularly where it is necessary to cool complex thin wall geometries in injection moulded compo- nents, according to GWK. The company says the high enthalpy of evaporation of the injected fluid at a temperature of -76°C offers extremely efficient heat transfer. But the company says its Vario GT system extends the potential
from an economical and from an ecological point of view,” says GWK development manager Guido Peters. “In addition, this type of tempera- ture control – unlike other processes – does not impose any challenging requirements regarding water quality, temperature, pressure or volume flow. The use of waterless injection moulds in clean rooms is thus within reach.” The Vario GT system is
by using CO2 both as a cooling and heating medium. The Vario GT system
compresses the CO2 gas to a suitable pressure and heats it close to the mould cavity. GWK says that, unlike water or hot steam, the CO2 medium
remains in an uncritical state even at high temperatures. Users also benefit from complete elimination of the risk of cooling channel blocking. “Temperature control using CO2 is a sound choice, both
intended for use with GWK’s Integrat 4D close-to-the-cavity mould cooling channel technology. This allows the fastest and vmost precise thermal transfer to be achieved. ❙
www.gwk.com
Roctool claims thin wall gains in electronics
French moulding technology company Roctool says that Taiwanese electronics industry moulder Ju Teng has adopted its mould temperature control for its latest thermoplastic composite smartphone and tablet casing production unit in China.
With more than 100 Roctool-equipped production
lines, the new $10m facility is claimed to be the largest of its type in the world. Smartphone and tablet casing components less than 0.5mm thick are produced in thermoplastic composites using glass and carbon reinforcements, according to Roctool. “Ju Teng has not only
developed an expertise on
complex part designs that are removed directly from the mould, but also the finish which is essential to the touch and perceived quality. This is an unavoidable requirement in consumer electronic,” says Ju Teng International CEO Li-Yu Cheng. Roctool CEO Alexandre
Guichard says Ju Teng, which claims to have a 30% share of the global notebook casing market, produced more than one million smartphone parts in the final quarter of 2013 using its rapid moulding technologies. The electronics industry supplier aims to increase this to one million parts per month. During the K show last
year, Roctool demonstrated
www.injectionworld.com
two examples of production of thin wall electronic casings us- ing its moulding technology. The first demonstration was a hybrid part comprised of pre-formed thermoplastic carbon fibre composite overmoulded on an Engel machine at a rate of more than 400 parts per day. The second example was an
electronic tablet casing (pictured) with a 0.8mm wall thickness produced in a glass reinforced PC/ABS. “We are currently the only company capable of producing electron- ic housings using engineering plastics with fibre contents that do not require painting and their thickness is less than 1mm” says Guichard. ❙
www.roctool.com
March 2014 | INJECTION WORLD 47
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