Speed-regulated pump drive

Speed-regulated smartDrive pump drive increases energy efficiency
Sumitomo (SHI) Demag's speed-regulated smartDrive pump drive provides clear proof that the energy efficiency of hydraulic injection moulding machines can be increased. It produces optimum levels of effectiveness and energy savings of up to 40 per cent. The dynamic performance adjustment of the pump drive motor, allowing every cycle phase to be individually adjusted, helps contribute to these benefits.
Sumitomo (SHI) Demag integrates smartDrive into hydraulic injection moulding machines in the Egotech series within its retrofit operating programme. Refitting the machine with the speed-regulated pump drive is the simplest way to achieve considerably lower energy consumption and, consequently, more cost-effectiveness. All that is required is the installation of a frequency converter in front of the asynchronous pump drive motor to be able to regulate the speed of the latter. If an operator decided to equip the drive of their injection moulding machine with a dynamic servomotor and a fixed displacement pump instead of a converter, they would need to invest a considerably higher amount.
Frequency converters can be adjusted to each processing phase
The functions of the smartDrive can be operated via the NC4-control of the machine. The machine is switched from standard operating to energy-saving mode by operating a switch point. Every machine axle or every processing phase can then be flexibly switched into or out of the smartDrive energy-saving function by the operator. During the injection moulding process, for example, the injection phase can be operated in standard mode, but the hold pressure process can be operated in energy-saving mode. The "High Dynamics" function allows the dynamic speed of the pump drive to be increased in good time before a machine axle actually starts up. The time readings displayed for at-rest and active smartDrive phases, referenced to the overall cycle time, allow the operator to obtain a precise energy
analysis for the cycle. As the user can flexibly allocate the energy saving function to the individual machine axles and process phases and does not have to let the entire cycle be affected, the smartDrive solution wins out over frequency converters working according to other designs. This is especially true, as there are functions for which converters would react too slowly and thus, for example, the cycle time, processing reliability or product quality could be neglected. If an operator would like to manufacture certain parts on their injection moulding machine with the energy saving mode switched off, then this is also possible without any restrictions.
Corresponding to the respective setting of the converter control which can be operated, smartDrive automatically matches the motor speed to the requirements determined by the cycle and ensures just that level of performance which the machine requires for every cycle sequence. This dynamic coordination with all phases of the injection moulding cycle means that Sumitomo (SHI) Demag can achieve optimum effectiveness levels with minimum losses. This is especially true for partial load and idle speed operation as well as for tooling, equipping and installing procedures. The overall consumption also drops during a longer turning phase in the cycle, as greater percentage savings can be made in this stage. The benefits derived from smartDrive also include low mechanical wear of the pump drive motor and of the pumps, which is due to the fact that the motor runs at a lower speed in many phases. In addition, the hydraulics system requires less oil cooling due to the pumping pressure generally being lower.
Saving potential of up to 40 per cent
The saving potential enabled with smartDrive is considerable. In an automotive use with a cycle time of 61 seconds, for example, 18 per cent in energy savings can be made in relation to the overall consumption by the motor. Savings of even 26 per cent are possible in consumer production at a cycle of 30 seconds. The differences are based on the fact that the savings potential and the return on investment of relevance to the customer strongly depend on the cycle or process. At very high pressures, therefore, the speed cannot be reduced in the phase concerned. The savings potential, which varies between 15 and 40 per
cent in Sumitomo (SHI) Demag's experience, is consequently smaller in such a case. Cycles of 15 seconds and upwards duration usually offer adequate savings potential to justify fitting the smartDrive system.
Using the EnergyCheck service offered by Sumitomo (SHI) Demag enables the energy consumption of an injection moulding process and its cycle phases to be measured prior to any decision being taken as regards smartDrive. This results in the user receiving information as regards the actual consumption of energy for their individual production parts. In addition, they can already work out beforehand how much energy they would save by installing the speed-regulated pump drive.
Tried and tested in tough practical deployments
The smartDrive system has in the meantime been tried and tested to great effect by many users in demanding practical deployments. An example of this is provided by Mann+Hummel, development partners and serial suppliers to the international automobile and engine construction industry. The manufacturer, which focuses on the production of filtering systems, operates an ‘Egotech 500’ injection moulding machine system, which has 5,000 kN clamping force and is equipped with an NC4-control. The company had a smartDrive installed in their machine as part of their in-house ‘energy efficiency’ project, aimed at reducing CO2 emissions. Dr.-Ing. Alrun Spennemann, Mann+Hummel GmbH, Ludwigsburg, Project Director in the Injection Moulding and Welding Steering Group, is happy with the results of the modernising measure: "The retrofit has worked very well. Sumitomo (SHI) Demag completely retrofitted the injection moulding machine within one day. This dynamic performance adjustment enabled us to reduce energy consumption by the motor by 18 per cent on one of our continuous runs. Further benefits are provided by the lower production downtimes and smoother work-runs. We are very satisfied with the solution and have therefore already had a second Ergotech, with an 8,000 kN clamping force, retrofitted with a smartDrive."
A pioneering solution
With an eye to the future, operators benefit from the fact that Sumitomo (SHI) Demag install the frequency converter in an external switch cabinet when carrying out the retrofit. This means that the switch cabinet and the converter can be used on the next model, once it no longer makes economic sense to extend the period of use of the machine in question. Given these facts, it is also likely to be financially worth-while to retrofit older machines, even if no pay-off on the investment in relation to this machine can be expected due to a probably short remaining running time. Apart from this, there are also government support programmes which can be accessed.
Sumitomo (SHI) Demag provides its customers with important operating tools in the form of the smartDrive and the higher energy efficiency resulting from its use. This enables them to counter the negative financial effects which have hit their production costs in the last ten years due to the doubling in energy costs. Moreover, smartDrive is in tune with the growing awareness of environmental issues which can be detected within society. The low noise emissions by machines equipped with the speed-regulated pump drive also contribute towards this as well.
Sumitomo (SHI) Demag has, after all, for years now already been making a considerable contribution to energy saving and to economical production means by the company continuously developing its injection moulding machines further. This commitment has been shown by numerous steps forward in development. These include the all-electric drive for dosing units, the hydro-mechanical closure system of the El-Exis hybrid injection moulding machine, which operates with a combination of electric and hydraulic drives, as well as the re-cycling of braking energy and the deployment of energy-efficient regulating pumps.
Supplementary measures against too high electricity consumption
Even further provisions for consuming less electricity can be made during a retrofit. Reduced electricity load peaks can especially be cited as an example of this. To this can be added the insulation of the cylinder heating, a power factor correction and lower electricity load during oil preheating. In addition, it is also possible to warm up with a shorter switching on period, to drop down in two stages after a cycle interruption during automatic operation and to install an interface for an external electricity load monitoring device.
Sumitomo (SHI) Demag's hydraulic machines contribute towards cost-effective injection moulding in just the same way as hybrids do, as they can both be configured in an optimum way. This means the processors are in a position to show their production requirements even more precisely and to achieve a more favourable price-performance ratio.

Main Menu

See Also

Main Menu