Low weight and good toughness thin plate parts are widely used in modern industry, but its flexibility seriously impacts the machinability. Plenty of studies focus on the influence of machine tool and cutting tool on the machining errors. However, few researches focus on compensating machining errors through the fixture. In order to improve the machining accuracy of thin plate-shape part in face milling, this paper presents a novel method for compensating the surface errors by prebending the workpiece during the milling process. First, a machining error prediction model using finite element method is formulated, which simplifies the contacts between the workpiece and fixture with spring constraints. Milling forces calculated by the micro-unit cutting force model are loaded on the error prediction model to predict the machining error. The error prediction results are substituted into the given formulas to obtain the prebending clamping forces and clamping positions. Consequently, the workpiece is prebent in terms of the calculated clamping forces and positions during the face milling operation to reduce the machining error. Finally, simulation and experimental tests are carried out to validate the correctness and efficiency of the proposed error compensation method. The experimental measured flatness results show that the flatness improves by approximately 30 percent through this error compensation method. The proposed method not only predicts the machining errors in face milling thin plate-shape parts but also reduces the machining errors by taking full advantage of the workpiece prebending caused by fixture, meanwhile, it provides a novel idea and theoretical basis for reducing milling errors and improving the milling accuracy.

Yttria-zirconia (3Y-ZrO ₂ ) ceramics are widely used in orthopedic implants and carbon nanotubes (CNTs) attract the public attention due to their unique properties. To investigate the effect of graphene oxide (GO) concentrations on the mechanical properties and tribological behaviors of 3Y-ZrO ₂ for dental implants, 3Y-ZrO _2/ GO composites were prepared by hot-press sintering. GO was uniformly distributed in 3Y-ZrO ₂ and the composites showed good mechanical properties and tribological behaviors with suitable GO concentration. A moderate content in ZG3 and ZG2 (the ceramic with 0.15 wt.% and 0.1 wt.% GO) improved the flexural strength and fracture toughness up to 200% and 40.9%, respectively, compared to 3Y-ZrO ₂ . Microstructural surfaces presented crack deflection, crack bridging, and GO put-out in the composites. In addition, a lower or higher proportion of GO destroyed overall structures of ZG1 (the ceramic with 0.05 wt.% GO) and ZG4 (the ceramic with 0.2 wt.% GO). These not only reduced the mechanical performances, but also resulted to an increase in surface roughness. Besides, Worn surfaces showed micro-ploughing and plastic deformation were dominant wear mechanisms in the ZG0 (the ceramic without GO), however, the addition of GO transformed the wear from a severe state to mild owing to self-lubricating property. Thus, friction coefficient, wear rate and surface roughness of ZG3 were reduced to the least among all the composites.