Technology Ways to increase the energy efficiency of cutting processes
Energy is constantly becoming more expensive. By analysing the energy consumption of cutting machine tools and the cutting processes, concrete leverage points for raising energy efficiency can be identified, according to Eckehard Kalhöfer and Jochen Kress.*
The use of energy is indispensable in modern production and industry. The global growth of populations, the rising standard of living and economic growth are forces pushing energy consumption ever higher.
Conversely, the world faces the limited availability of energy sources such as coal, oil or also bio-fuels. The rising demand for energy along with its simultaneous limitation is leading to higher energy prices in the long term. Against this background, the energy efficiency of production processes is a driving force for technology which will enable modern production in the future as well. But how, and with which adjustment screws, can concrete improvements in energy efficiency in cutting production be achieved?
If one takes into consideration the energy consumption of the machine tool, including the lubrication system, differing approaches for boosting the energy efficiency could be defined:
- The optimisation of the machine tool and its components with respect to energy consumption.
- The minimising of the running time by switching off during non-production.
- The optimisation of cutting and the tools used for it.
Variable-speed pumps cut energy consumption of CLS unit
The energy consumption of production machines themselves typically has a share of 80% of the total consumption in predominantly cutting-based large-scale series production. The cooling lubricant system supply has an over 50% share in this. Further large shares in the energy consumption are due to the machine cooling, the drive train and the hydraulics.
The energy consumption of the cooling lubricant unit can be reduced above all by a needs-oriented supply of cooling lubricant – i.e., by using variable speed pumps. As a result, the energy consumption of the cooling lubricant unit can in some cases be lowered by 60%. The energy requirements of the entire machine can be lowered in this example by 30% alone merely by optimising the cooling lubrication.
Cutting machine tools are typically on main time only a third of the time or less. The remaining machine running time is waiting time and time for adjustments and tool changes. Two conclusions can be drawn from this for energy efficiency. During these non-productive times, non-essential components with high energy consumption should be switched off by automatic standby-managers. In some cases, these measures can enable saving of over 20% of the total energy of the machine tool.