Non-contact measurement and analysis of machine tool spindles

Abstract

Increasing demand on the manufacturing industry to produce tighter tolerance parts means it is necessary to gain a greater understanding of machine tool capabilities and error sources. A significant source of machine tool errors is down to spindle inaccuracies and performance, leading to part scrapping. Catastrophic spindle failure brings production to a standstill until a new spindle can be procured and installed, resulting in lost production time. This project aims to assess the effect of these errors on part production, dependant on machine and operation, with a view to enabling easier spindle checks and therefore predictive maintenance. This will be achieved through investigating existing and new non-contact measurement technologies to establish which is best suited to meet all required outcomes. There are two main positional error sources investigated in this project, non-rigid and geometric. Nonrigid error sources will include investigations into spindle bearings and the cause and effect of vibration. Geometric error will look at the spindle position relative to the machine tool including radial and axial displacement. However, thermal expansion is also considered as it is the biggest cause of machine tool error, often affecting machine tool geometry. There is one sensor system currently available on the market, which is expensive and ideally only used in a clean environment due to the type of sensor technology being used. Therefore, throughout this project various non-contact measurement technologies will be reviewed for their suitability for efficiency in industry. The successful completion of this project will result in new efficient and versatile spindle measurement and analysis techniques