| Enhancing the accuracy of Computer Numerically Controlled machine tools is a common goal of machine tool builders and end users. The use of higher accuracy machine tools directly translates to higher quality products that cost less because scrap and rework costs are reduced. One way to improve the accuracy of machine tools, which was the focus of this research, was to characterize the quasistatic errors of the machine and use a software compensation scheme to reduce or eliminate most of these error components before and during the machining process. This study presents the application of the ASME B5.54 Standard as a methodology for collecting parametric error data which was subsequently used in a kinematic model of a machine tool. The kinematic model was used to predict the error associated with any (x,y,z,b) orientation in the work envelope of a machine tool. The error predictions were used with a software compensation scheme to modify the numerical control program that drives the machine tool and to calculate part alignment errors during machining through the use of on-machining probing. Cutting tests using both compensated and non-compensated numerical control programs were performed to verify the extent of accuracy improvement. |
