The ultra-precision U-d-lap grinding of flat advanced ceramics

Abstract: The present study focuses on the U-d-lap grinding process and its machine-tool design aiming at ultra precision (UP) manufacturing of advanced ceramics. Impacts of three different overlapping factors on a dressing (U-d) and three abrasive grit sizes of conventional SiC grinding wheels were analyzed on flat nano metric surface finishing of dense discs of 3Y-TZP in a ductile regime of material removal. Microhardness, contact and optical profilometry, SEM-FEG, Raman spectroscopy, XRD, and confocal epi-fluorescence were applied to characterize the ceramic material. Mechanical and electric-electronic designs of the machine-tool were developed toward the UP ceramic grinding. The design methodology was successful for supporting the achievement of all design requirements of the CNC Fiocchi Lap Grinder. The machine tool and the U-d-lap grinding process were capable of manufacturing flat 3Y-TZP surfaces with nanometric finishing without introducing critical defects. The best finishing, Ra = 60.63 nm, came from the #300 grinding wheel dressed with U-d = 5. A flatness deviation of 0.308 mu m was obtained through the #800 grinding wheel and U-d = 3. Differences between theoretical and real macro and micro effects over the grinding wheels after single-point diamond dressing, epoxy bond strength, abrasive protrusion, abrasive grit size and abrasive friability play a key role in the U-d-lap grinding. There is no report of an abrasive process capable of achieving similar nanometric finishing without introducing critical defects with the same micrometric grit size and type of abrasive. The U-d-lap grinding can replace the engagement of processes such as grinding, lapping, and polishing of advanced ceramics. (C) 2016 Published by Elsevier B.V.

Author(s): Fiocchi, AA; Sanchez, LED; Lisboa, PN; Fortulan, CA

JOURNAL OF MATERIALS PROCESSING TECHNOLOGY

DOI: 10.1016/j.jmatprotec.2015.10.003