TECHNOLOGY | SMART FUNCTIONS
rate can be reduced. It is able to account for large viscosity changes, for example a mix of two PP types with a difference in viscosity of approximately 100g/10min. This is for use in situations where there are viscosity fluctuations between material batches, for example, plastics containing differ- ences in glass fibre content and applications where regranulate or recycled materials are used.” He says: “HiQ Melt measures the work required metering material. This software packet is an early warning signal to stop production when material discrepancies occur, possibly from an incorrect material change and thus stops the machine as early as possible, further reducing the scrap rate. Finally, HiQ Metering is a program step between end of metering and start of decompression. By using particular movements of the screw that are specific to the current melt pool properties, the check ring is depressurised and brought into the ‘closed’ position in preparation for the following injection step. This stabilises the filling times and melt cushion readings. This is because injection starts when the screw begins to move without having to firstly shut the check ring. Another benefit is that pressures within the screw are released at the end of metering without being allowed to leak into the antechamber.”
Viscosity variation Wittmann Battenfeld adds that it was recently involved with a customer in the automotive industry for safety relevant components. The company was having issues with a viscosity change in its material. The polyamide material it was using contained 40% wt glass fibre. Fluctuations in the material’s glass fibre content caused unstable viscosity deviations. Using weight as the quality reference criterion did not work due to the varying glass fibre content, resulting in fluctuating material densities. Hence, the part weight did not correlate with the correct part dimensions. Instead, the maximum cavity pressure was used as the quality parameter. HiQ Flow was able to maintain a much more consistent peak cavity pressure and could be a cost-effective replacement to having cavity sensors in every cavity. “Within the next few years, we expect to see
smart functions becoming more user friendly with single button set-ups,” adds Pearson. “Along with the ability to optimise processes and reduce waste, they could also help to achieve optimal energy usage. They would also give the user more infor- mation about what is occurring during the process, for example the melt quality, and give suggestions on how the process could be improved.”
38 INJECTION WORLD | October 2020
Above: Wittmann Battenfeld’s HiQ Flow automatically adapts the switchover point and the following holding pressure, within the same shot, to account for fluctuations in the material viscosity
According to Fanuc, smart functions can provide
an extremely high level of process control, which will have a massive impact on the injection mould- ing process. “Smart functions allow the process of controlling the melt and melt quality to be quickly and automatically adapted, which in turns allows for a more repeatable process,” says Andy Armstrong, Sales and Marketing Manager at Fanuc UK. “Not only does this help to ensure consistency of product and improve productivity by reducing the amount of scrap, but it can also increase production yields and reduce the need for human machine intervention. One of the most important factors for manufacturers, and particularly injection moulders, is uptime. Keeping equipment running for as long as possible, working effectively and efficiently, is absolutely critical to productivity, and therefore profitability. Smart functionality helps to make processes more repeatable, which reduces the amount of downtime associated with an injection moulding machine, and ultimately ensures utilisa- tion rates are greater in terms of yield.” He says: “This is where all-electric injection moulding machines, such as Fanuc’s Roboshot series, are perfectly suited to maximising the output of an injection moulding shop. Feedback from the drive elements can provide instantaneous information, allowing smart functions to deliver a better process control while increasing equipment uptime. The ability to get a mould running reliably without intervention or human input is a big benefit, and one that ultimately allows the mould- ing facility to increase its output, even in the face of potential skills shortages.” He continues: “The other way in which smart functionality can increase uptime is by predicting where issues may occur, before they cause the
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IMAGE: WITTMNAN
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