European Guidelines on Energy Efficiency of Moulding Machinery Open to Manipulation?
Europe’s association for plastics and rubber machinery manufacturers, Euromap, has revised its guidelines for comparing energy efficiency between various injection moulding machines. They now separate the guidelines into two parts—machine- and product-related consumption. Euromap’s statement on the revision is as follows.
Energy efficiency has been an issue for the plastics and rubber machinery industry for quite some time. The EU Ecodesign Directive and, not least, customer demand for transparent and comparable energy consumption figures have brought fresh impetus to the subject.
The existing Euromap 60 on the determination of the energy consumption of injection moulding machines was itself an important step forward in open debate on the subject but, despite the intensive measurement effort made, failed to provide the sought after comparability because factors such as the measurement parameters were not adequately defined. For that reason, the recommendation has now been thoroughly revised. In response to calls for comparable measurement results on the one hand and to take account of the variability of machines on the other, the recommendation has now been divided into two parts 60.1 and 60.2.
Machine-related consumption: The new version gives customers an opportunity to compare machines from different manufacturers on the basis of uniform parameters. It introduces an energy efficiency classification based on two test cycles that take the particular characteristics of fast running machinery and very small machines into account. Keeping the measurement effort required to a level acceptable to machinery manufacturers without the results losing any of their information value is an important consideration here. The efficiency classes identified serve as benchmarks allowing customers to make a pre-selection. Not least, the uniform classification enables increases in efficiency to be put across clearly, including to the political decision-makers.
Product-related consumption: In addition to the rough classification of injection moulding machines, the second part of the new recommendation offers the possibility of transparency in product-related energy consumption for the manufacture of individual injection-moulded parts to customer specifications (with specified materials, tools and machinery). The key parameter here is the specific energy consumption in kilowatt-hours per kilogram (kwh/kg) of plastic processed. To this end, a method of measurement with defined terms of reference is provided, together with a model for documenting the results. This will allow customers to include energy consumption in the machine’s life cycle cost calculation at the tendering stage.
Comment: Medical Plastics News asked a selection of leading injection moulding machine manufacturers and experts to comment on the revised guidelines. Dr Karlheinz Bourdon, vice president of injection moulding technologies at Germany’s KraussMaffei Group, owner of the KraussMaffei and Netstal brands, said: “For a long time, we have pushed for the EM60 to be made more user-friendly. We have been heavily involved in the update and we will continue to support this guideline. In particular, the new two-stage configuration based on machine classification and defined specifications for product-related use with moulds meets the desire to have more objective comparability.”
But UK-based independent injection moulding engineering consultant Robin Kent of Tangram Technology still sees potential shortcomings, which could make the guidelines open to manipulation by machine manufacturers. He said: “While the revised guidelines are a step in the right direction they assume that for screw diameters of greater than or equal to 25 mm the specific energy consumption (SEC) in kWh/kg is constant for all production rates and this can be used to rate the machine. Results from our own experiments on energy efficiency show the SEC is dependent on the production rate (kg/h), especially for small machines.” He added: “These concerns could potentially open the standard up to manipulation whereby mmachines could be tested at high production rates to gain better ratings.”
Daniel Heinzelmann of German manufacturer Arburg echoed these comments, saying overall the revision is a positive step but there are still areas for improvement. “The definition of a brochure value is problematic because too many factors can influence a machine’s energy requirements and these cannot be recorded in a single value,” he said. Daniel added: “Although customers can compare machines from different manufacturers, it is not possible to determine the actual energy requirements of a specific process. It is almost impossible to compare different machine technologies. For example, the Arburg energy-saving system for hydraulic machines or servo-hydraulic systems can save more energy with longer cooling times than with short cycle times.”
Daniel went on to say: “We welcome the introduction of efficiency classes as a first step in offering customers greater transparency. In this context, however, it is important to emphasise that energy requirements largely depend on the process. The energy efficiency classes only allow machines with the same machine technology to be compared. It is important to indicate the pump and motor outputs. When dealing with different machine technologies, energy requirements need to be determined on a process-specific basis in order to obtain meaningful results.”
On March 12, 2013, Arburg announced the winner of its fifth energy efficiency award, German manufacturer of motors and drives AMK. Demonstrating Arburg’s commitment to energy efficiency, the award is given to one of Arburg’s suppliers each year and began in 2008.
Medical Plastics News welcomes comments to the editor at sam.a@rapidnews.com.