Energy-efficient control of dust extraction for the machining of fibre-reinforced plastics

Abstract

Fibre-reinforced plastics (FRPs) are becoming increasingly important in aerospace and automotive applications. However, dry machining of FRPs generates abrasive and electrically conductive dust particles that can furthermore cause explosive dust-air mixtures in the enclosed workspace of the machine tool. In order to protect the machine operator and the machine tool, powerful extraction systems (engine power > 5 kW) are usually installed and operated with a constant flow rate, resulting in a significant increase of the machine tool’s overall energy requirement. This paper introduces a novel approach for a demand-oriented control of the flow rate to increase the energy efficiency of dust extraction systems. The objective of the developed control mechanisms is to maintain the maximum permissible dust limit with minimum energy demand. A low-cost dust sensor serves as a feedback system for the applied control mechanism. In a further stage, a force measuring platform was added to provide additional signals for an increased performance of the controlled system. To evaluate the presented approach, milling tests were carried out with carbon-fibre-reinforced plastic (CFRP). The experimental results show that the energy requirement can be reduced by up to 70%.