Open AccessCompensation strategy for machining optical freeform surfaces by the combined on- and off-machine measurement
Author(s) -
Xiaodong Zhang,
Zhaofa Zeng,
Xianlei Liu,
Fengzhou Fang
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.024800
Subject(s) - fixture , compensation (psychology) , machining , coordinate measuring machine , machine tool , computer science , position (finance) , machine vision , numerical control , mechanical engineering , optics , artificial intelligence , engineering , physics , psychology , finance , psychoanalysis , economics
Freeform surface is promising to be the next generation optics, however it needs high form accuracy for excellent performance. The closed-loop of fabrication-measurement-compensation is necessary for the improvement of the form accuracy. It is difficult to do an off-machine measurement during the freeform machining because the remounting inaccuracy can result in significant form deviations. On the other side, on-machine measurement may hides the systematic errors of the machine because the measuring device is placed in situ on the machine. This study proposes a new compensation strategy based on the combination of on-machine and off-machine measurement. The freeform surface is measured in off-machine mode with nanometric accuracy, and the on-machine probe achieves accurate relative position between the workpiece and machine after remounting. The compensation cutting path is generated according to the calculated relative position and shape errors to avoid employing extra manual adjustment or highly accurate reference-feature fixture. Experimental results verified the effectiveness of the proposed method.