Automatic Error Compensation for Free-Form Surfaces by Using On-Machine Measurement Data

Abstract

Currently, most computer numerical control (CNC) controllers lack the function needed to compensate machining errors for free-form surfaces. The objective of this research was to enhance the accuracy and precision of the machined free-form surfaces of a workpiece using the mirror compensation method with the on-measurement data. By mirroring the points measured after semi-finishing, a new free-form surface for finishing machining can be automatically reconstructed. The surface can then be used to generate the cutting tool path to reduce the errors during finishing machining. In this research, three different types of surfaces were used for evaluating the proposed method. The results show that the proposed method reduced the standard deviations of the three surface geometries by 61%, 61%, and 32%, respectively. We also evaluated the tool radius modification method commonly used in the industry for error compensation and found that there is no substantial reduction on standard deviation. Therefore, the effectiveness of the error compensation method proposed in this research is evident.

Decomposition of machining error for surfaces using complete ensemble empirical mode decomposition with adaptive noise

“…However, the EEMD algorithm cannot completely eliminate Gaussian white noise after signal reconstruction, as it causes reconstruction errors (Cao, Li, and Li 2019). To overcome these challenges, CEEMDAN, which can provide an exact reconstruction of the original signal and better spectral separation of the modes with a lower computational cost (Wang and Shao 2020), improves EEMD.…”

“…To use off-line inspection, because the workpiece needs to be unmounted and then carried to another location, there will be re-clamping errors. On the other hand, using on-line inspection does not need to be unmounted, will not cause re-clamping errors, and can also reduce the time and efforts for re-clamping (Lee, Lee, and Wei 2019).…”

Special Issue: Selected Papers from IEEE ICASI 2019

“…The experimental results show that the proposed scheme achieves the best matching accuracy when compared with six well-recognized cutting-edge algorithms using version 3 of the Middlebury stereo evaluation data sets. W. C. Lee et al [5] reported on "Automatic Error Compensation for Free-form Surfaces by Using On-machine Measurement Data". Currently, most computer numerical control controllers lack the function needed to compensate machining errors for free-form surfaces.…”

Geometric Measurements on a CNC Machining Device as an Element of Closed Door Technology

“…CDT is characterized by the full use of production capabilities thanks to better planning of workshop tasks and maximum reduction of human factor impact on the production process [ 3 , 4 ]. With the use of closed door machining, the operators play a different role than in the case of traditional machining methods [ 5 ].…”

“…In article [ 9 ], the authors searched for a general model to evaluate measurement repeatability for a five-axis machine in any measurement situation. In articles [ 1 , 4 ], the authors implemented on-machine measurements to gain information about machining quality and adjust the milling process. In article [ 3 ], the authors implemented measurements on a machine to calibrate the cutting process and compensate for the effect of susceptibility.…”