Open AccessFiducial-aided on-machine positioning method for precision manufacturing of optical freeform surfaces
Author(s) -
Shixiang Wang,
Chi Fai Cheung,
Mengye Ren,
Mingyu Liu
Publication year - 2018
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.26.018928
Subject(s) - fiducial marker , coordinate measuring machine , machining , compensation (psychology) , machine tool , computer science , position (finance) , cad , precision engineering , computer aided design , computer vision , optics , mechanical engineering , engineering drawing , materials science , engineering , physics , psychology , miniaturization , finance , psychoanalysis , economics , nanotechnology , operating system
There are still significant challenges in the accurate positioning of optical freeform surfaces on the machine tool and the measurement instrument due to the high accuracy requirement and their complex shapes. This paper proposes a Fiducial-aided On-machine Positioning method (FAOPM) that combines on-machine measurement and off-machine measurement to precisely position optical freeform surfaces during the precision manufacturing cycle including rough machining, fine machining, measurement, and error compensation. The FAOPM makes use of fiducials which are firstly measured on a coordinate measuring machine with nanometric accuracy to generate a Fiducial-aided Computer Aided Design (FA-CAD) of the designed optical surface, then the developed on-machine measuring device obtains the accurate positions of the fiducials after remounting in the machining coordinate system. Finally the relative position of the workpiece is identified so that the associated cutting paths and compensation tool path can be easily generated. Several optical freeform surfaces were experimentally machined to prove the capability of the proposed method. The results indicate that the positions of the workpiece during the precision manufacturing and measurement cycle were precisely achieved and the form accuracy of the optical freeform surfaces was remarkable improved based on the FAOPM.