Industrial production inevitably results in an environmental impact. Energy consumption is responsible for a substantial part of this impact. Currently, machine designers spend little attention to minimising the energy consumption, since their primary focus is on the well-functioning of the machine. This paper indicates the potential for energy improvement measures. According to Gutowski et al [1], a major part of the total energy consumption of a machine does not depend on the production rate, but is fixed. This paper searches for possible measures to reduce this independent fraction. Another aspect is the importance of the machine occupancy: in a lean manufacturing approach, machines only operate when a product order is released. This implies a constant availability of the machine in a stand-by mode, since high flexibility is required, while the actual processing time may be limited. This paper audits these energy aspects for two discrete part producing machines types: a press brake and a multi-axis milling machine, and proposes initial design improvements to reduce the overall energy consumption. The possible economical and environmental impact of such energy saving measures from a life cycle perspective is quantified in order to allow cost-benefit analysis.
