Injection Moulding Asia Machinery
Machinery becoming more energy efficient In a study conducted by Euromap, the European plastics and rubber machinery association, it has been determined that the industry is well-placed to cut machine-related energy consumption by around 20% by 2020.
Servo drives gaining ground ncreasing use has been made of servo drives in cyclic processes such as injection moulding, blow moulding and vacuum forming technologies for a number of years now. These allow the energy required for motion to be cut by half. Plants with a conventional, central power source and system-related line and control losses are increasingly being replaced. Servo engineering has long since made the breakthrough in such high-performance areas as packaging and medical engineering. Servo systems now also offer simple solutions for energy recuperation. In injection moulding, for example, during rapid motion of the closing units, the drives are used as generators to produce energy when braking. The same principle is also used with fast-working closing units of blow moulding machines and in thermoforming machines.
Productivity goes hand in hand r Urbanek, author of the Euromap study “Energy Efficiency: European Plastics and Rubber Machines Well Placed”, sees close links between energy efficiency and productivity. “Investing for greater productivity generally also means investing in energy efficiency,” he says. The potential savings highlighted by the study satisfy the strict criteria laid down by the European Commission to cut European energy consumption by 20% by 2020. The study looked at the main plastics and rubber processing technologies, ie. injection moulding, extrusion, blow moulding and thermoforming, which account for around 90% of the total volume processed. Looking back, the author determined that production efficiency has almost doubled in 20 years and plastics machinery’s specific energy consumption is down 30%. The study also reports that machines are now capable of a manufacturing output that would once have required twice as many machines of similar size. Developments in manufacturing technology have provided a significant performance boost. The demands made on hydraulic systems have resulted in greater efficiency and cut the energy consumption of injection moulding machines by around 40%. The throughput capacity of extrusion machines has also doubled over the same period. Machine-related energy consumption has been reduced by around 20%. The same is true in compounding: twice the amount of material is being processed with machine-related energy consumption down by 20% at the same time.
Outlook for the future ooking to the future, there is no doubt that the use of energy-saving and highly dynamic components will provide a significant boost in terms of improving energy efficiency further in the next ten years. Greater use of all-electric drives and servo-hydraulic designs instead of conventional technology will pave the way for further efficiency gains – in some cases as much as 50%. The most important part in improving machinery is played by developments in process engineering: advances in screw technology have brought a significant increase in throughput rates while at the same time improving the quality of the melt. This has allowed extruders and the injection units of injection moulding machines to become smaller and better while maintaining performance. Radiant heater systems show great potential in thermoforming machines. There is also a great deal of potential for combining several processes: this is of particular interest if residual heat from one stage in a process can be used in the following stage with a view to eliminating reheating altogether.
How the energy is used nergy consumption is estimated on the basis of the European machine population in 2010 and the average specific energy consumption per unit of processed material. This gives an annual machine-related energy consumption of 22.8 terawatt hours (TWh). Total energy consumption by the converters where these machines are used is around three times as high at 66.5 TWh. Apart from machines, this figure includes the firms’ entire production and management infrastructure, in other words such consumers of energy as heating, cooling, compressed air, etc. Furthermore, about one-third of machine-related energy consumption is a constant, which is required simply for the process of melting plastics (enthalpy). This energy consumption cannot therefore be reduced, not even by using more efficient machines.
Energy monitoring worthwhile ajor savings can also be achieved if converters finetune processes to minimise energy consumption. Monitoring the flow of energy in machines, installations and in the plant also produces results. It makes the energy requirement transparent, which in turn contributes to tailoring energy consumption to need. This will ultimately reduce operating costs, incidentally helping them meet the European Commission’s target. When applied to all machine technologies, the reduction in machine-related energy consumption achievable with these measures will make for potential savings of 4.5 TWh in 2020 as compared to 2010.
4 JANUARY / FEBRUARY 2012
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IMA Features 2012 January-February