An antistatic device to decrease friction induced electrostatic charge in precision machining processes

摘要

The increasing functionalization of surfaces and the need for function integrated components demands for highly efficient and precise machining processes. Processes are for example micro milling and high speed cutting. These processes are highly flexible and can be used to machine a nearly unlimited variety of workpiece materials. Nevertheless, they are characterized by high friction in the contact zone due to the low undeformed chip thicknesses. This friction creates a potential difference and thus a static charge. To reduce this static charge for air bearing axes and spindles, a non-contact grounding is needed. This was achieved in this research by an antistatic device, which creates ionized air and injects it near the contact zone between tool and workpiece. The air ionizes dust, tool and workpiece equally and thus compensates the potential difference. The suitability of the antistatic device was tested by micro and high speed machining. As a result, the ionized air reduced the spark discharge just like a mechanical contact. This helps to enhance the efficiency of micro and high speed milling processes due to the possibility to use high speed air bearing spindles. This ultimately leads to the possibility to produce even greater and more function integrated surfaces and components in a smaller period of time.