Prediction of machining accuracy based on a geometric error model in five-axis peripheral milling process

Abstract

Machining accuracy is the most critical indicator to evaluate the machining quality of parts in metal cutting industry. However, it is difficult to be identified before real cutting, because of a variety of error sources presented in a machining process system, such as assembly inaccuracy of machine tool, deformation caused by temperature variation and dynamic cutting force, tool wear, servo lag and so on. Consequently, it is difficult to determine whether a new machining process can satisfy accuracy requirements beforehand. Traditionally, a machining process is validated through the “trial and error” approach, which is time consuming and costly. If machining accuracy can be predicted to a large extent, a rational process can be planned to ensure the precision of parts and even to maximize resource utilization without trial cuts. For this purpose, this work focuses on machining accuracy prediction for five-axis peripheral milling based on the geometric errors. An error synthesis modeling method is proposed to integrate the geometric errors of the process system, including machine tool geometric error, workpiece locating error, cutting tool dimension error and setup error. From a multi-body system point of view, all these errors are synthesized to generate position error of the cutting contact point in the workpiece coordinate system. Then the machining error is obtained by projecting the position error to the workpiece normal vector, which can be measured by a coordinate measuring machine. The prediction model has been evaluated by a cutting test with our in-house-developed prototype software. The result shows that the proposed method is feasible and effective.

Integration of tool error identification and machining accuracy prediction into machining compensation in flank milling

“…Reference [33] pointed out that the radius i R can be measured by laser tool measuring system, when measuring, the tool is mounted on the spindle and rotates with it, then tool moves downward along Z axis with a distance of d, a few seconds to stay and the rotation radius can be measured.…”

“…According to the identification results of the tool errors, the machining accuracy can be predicted. In the early work, we proposed a prediction model [33] considering the influence of geometric error of machine tool and workpiece locating error. The tool contact points between the tool profile and workpiece play predominant roles in generating the milled surfaces [36], and these points can be calculated by the preexisting prediction model.…”

An investigation on modeling and compensation of synthetic geometric errors on large machine tools based on moving least squares method

“…However, the accuracy of machine tools is severely affected by a variety of error sources, such as geometric errors, thermal errors, cutting force-induced errors, servo errors, and tool wear. [1][2][3][4] And compared with conventional-sized machine tool, large machine tool shares a poorer geometric stiffness and thermal stability due to its large structure, the transverse beam would bend due to its own heavy weight and then results in significant positioning error and straightness error. 5 Furthermore, angular error would also generate significant influence on the spatial positioning accuracy due to the long translational axis.…”

Adaptive robust control of machining force and contour error with tool deflection using global task coordinate frame

“…Most attempts to control CE ignore the effects of tool deflection, which can be a significant source of error in machining applications. Attempts to correct for tool deflection typically modify the tool path before cutting according to predictions from previously identified deflection or forces [10][11][12][13] or modify the pre-finish path 14 to setup a final pass that exhibits constant cutting force and deflection. The approach used in this study embeds the tool deflection and axis dynamics in a single system for online control of both sources of CE.…”