Parker drives help cut energy consumption by half

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Parker SSD and NRG have worked together to develop a system that can be used to cut the energy consumption of injection moulding machines by over 50 per cent.

Parker drives help cut energy consumption by halfA partnership between Parker SSD and NRG, a firm of energy management specialists, looks set to help injection moulding companies cut the power consumption of moulding machines by more than half without affecting machine performance.

With technical and product support from Parker SSD, NRG has developed an innovative system for managing the energy used by motors that control the hydraulic functions in injection moulding machines. This system is based on a combination of comprehensive analyses of individual machine characteristics, with the ability to implement predictive and precise control of motors and associated devices using a specially developed SyncroSpeed system, which incorporates the latest Parker drive technology.

Rob Parkes, Business Development Manager at NRG, explains: "Energy consumption is one of the biggest costs for injection moulding companies, with speed and pressure requirements often fluctuating considerably throughout each machine cycle; for example, high pressures during tonnage build-up, hold on injection and cooling phases, while lower yet still variable pressures are needed for all other phases of the moulding cycle. These frequent changes in power demand during each machine cycle are especially noticeable in jobs with cycle times of over 30 seconds or where thicker wall sections require extended hold and cool sequences."

Drawbacks of unsophisticated controls

In most injection moulding machines the control mechanisms, although accurate, are generally unsophisticated. As a result, the systems on each machine that consume most power are often set to deliver maximum pressure or flow regardless of the actual process requirements at any moment in time. Rob Parkes adds: "The most common power units are AC induction motors coupled with fixed-delivery hydraulic vane pumps; these offer low capital cost and reliability but are only capable (with normal machine control systems) of delivering fixed outputs, irrespective of the operating conditions."

In comparison, the SyncroSpeed system offers maximum energy savings while retaining the full performance of the injection moulding machine, and can reduce the power consumption of drive motors by over 50 per cent. In essence, the system provides infinitely variable control of all motor functions, regulating control of speed and thus flow, pressure and volume to match instantaneous demand at the source point of the prime motor rather than elsewhere in the system. The SyncroSpeed system can be retrofitted to existing injection moulding machines and, once installed and setup, is effectively transparent to machine operation.

Key to the functionality and performance gains offered by the SynchroSpeed system is its use of Parker SSD drive technology. Rob Parkes is keen to stress the strong relationship between the two companies: "We see Parker SSD as the experts in drive technology, and they have worked closely with us in NRG's development of a dedicated microprocessor-based AC inverter system based on their proven 650V series products. These are supplied as integrated units, pre-tested and ready for us simply to plug in and set up. Just as importantly, Parker SSD have spent considerable time with our product development team and have provided considerable technical support to help us gain the maximum benefit from their drive technology".

The 650V drives have been developed specifically for use with open-loop AC motors, are quick and simple to configure and test on-site, and incorporate a wide range of features including IMC filters, 150 per cent overload protection, analogue, digital and motor thermistor inputs and a six-button, password-protected operator keypad with backlit LCD.

Rob Parkes concludes: "The 650V drives have proven themselves to be extremely tough and reliable, with considerable performance and functionality. In addition, they are supported throughout the world by Parker's network of manufacturing and sales resources, enabling us to ensure that we can provide our customers with the technical backup wherever their injection moulding operation is located."

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