Shaping of the Fresnel lens array on roller molds by 6-axis diamond machining. (December 2022)

• Record Type: Journal Article
• Authors: Chen, Junnan; Chen, Zaozao; Zhu, Limin; Ren, Mingjun; Zhang, Xinquan
• Is Part Of: Journal of manufacturing processes. Volume 84(2022)
• Page Start: 1557
• Page End: 1567
• Publication Date: 2022-12
• Subjects: Ultra-precision turning -- 6-axis diamond shaping -- Fresnel lens array -- Roller molds; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2022.11.016
• Languages: English
• ISSNs: 1526-6125

Abstract

Abstract: The Fresnel lens arrays are rapidly developing with the increasing demand for better optical performances and capabilities. For the roll-to-roll embossing of optical films, direct diamond machining of the Fresnel lenses on roller molds has been realized by installing an additional goniometer on the 5-axis ultra-precision machine tool in the previous study. However, this method owns two shortcomings, i.e., the communication delay between the machine tool and the goniometer and the poor positioning accuracy of the goniometer. In this paper, a 6-axis diamond shaping method is proposed to fabricate the Fresnel lens array on the roller periphery by utilizing a commercial 6-axis ultra-precision machine tool. It is ensured that the side cutting edge of the diamond tool matches the Fresnel lenses profiles during shaping. Also, the tool rake face is always perpendicular to both the roller tangent plane at the cutter location point and the cutting velocity relative to the roller via the synchronized rotations of the A-, B- and C-axes to avoid the tool–workpiece interference. The process to calibrate installation errors is introduced and utilized. The tool path is generated according to the cutting tool geometry, the lens parameters and the machine tool configuration. Experiments are carried out by machining the designed Fresnel lens array on a roller mold, which consists of lenses with different feature heights. The surface qualities of the lens arrays are evaluated and the influence of the block time to run the CNC code are also analyzed. The experimental results verify that the proposed method is effective and flexible for machining of the Fresnel lens array on roller molds. Highlights: A 6-axis diamond shaping is proposed to fabricate the curved Fresnel lenses. The principle of the 6-axis diamond shaping and the error calibration are presented. The 6-axis tool path generation algorithm is introduced and validated. The complete and mirror-like Fresnel lenses on the roller periphery are fabricated. The influences of crucial machining parameters on surface qualities are investigated.