An accurate characterization method to tracing the geometric defect of the machined surface for complex five-axis machine tools

Abstract

Geometric error is the main error that affects the machining accuracy of complex five-axis machine tool. Therefore, tracing analysis of error influence for a complex machine tool has been carried out based on an S-shaped workpiece in this study. A method of judging the error parameters which is the biggest influence on machining errors is established. In this method, the machining error of S-shaped workpiece and shaping motions of complex machine tool are comprehensively considered. Cubic B-splines surface has been applied to characterization of the curved surface. The actual position of tool center can be deduced by projecting the B-splines surface in its normal direction. The mapping relationship between the actual tool position and the actual machining curve has established. The machining errors generation model has established. The error expression equation has been deduced. Those five key parameters that have great influence on machining errors are determined according to the contribution which have been computed using the sensitivity and measured values of error parameters. Experimental results show that the error of each point is not more than ±1.5 μm by comparing the five error parameters and all parameters under the action of at the same time. The biggest errors which influence on the machining errors are ${\varepsilon}_{yC_1}$, δ _z (B), ε _y (C ₁), ε _x (C ₁), and ${\varepsilon}_{x_1{C}_1}$.