Improving dimensional accuracy by error modelling and its compensation for 3-axis Vertical Machining Centre

In today’s era, machining centres are very important units of manufacturing systems. Due to the structural characteristics, inaccuracy of the tool tip position is inherent. This could be a result of geometric error, thermal error, fixture dependant error and cutting force induced error. The geometric error contributes 70% of the total errors related to a machine tool. Present work focuses on improving dimensional accuracy of a 3-axis vertical machining centre (VMC). Accurate error estimation inmachine tools is possible using kinematic error model. Initially, kinematic model for an error free VMC with TTT configuration was developed using D-H convention. Subsequently, a kinematic error model was developed by same technique considering 12 geometric error components. The actual error measurement along each axis was carried out using 3D microscope and vernier depth gauge. The concept of interpolation function was used to predict error distribution in a workspace enclosure. An error compensation algorithm using predicted error was developed and was also validated experimentally.2nd International and 17th National Conference on Machines and Mechanism