Study on grinding deformation of Al2O3-TiC slender bar
The deformation of brittle and hard material slender bar has great significance in contour grinding process. In this paper, the grinding deformation for Al2O3-TiC slender bar was studied. Diamond lapping film and adhesive mounting method were applied in the experiments. The influences of grinding pressure, grinding speed and stress on deformation were discussed in detail based on the theoretical analysis and the measurement of straightness in different conditions. The bend deformation goes up with the increase of grinding pressure and speed. The internal stress will bring large deformation after grinding. Releasing the stress will improve the deformation. Experiments shown that releasing the stress two-thirds at a proper condition before final grinding can achieve the deformation below 1000nm. Employing lapping film and adhesive mounting method in optimal condition, the Al2O3-TiC slender bar deformation in grinding can be controlled.
Warp in High Precision Cut-Off Grinding of Al2O3-TiC Ceramic Thin Plate
Abstract High precision cut-off grinding has been carried out on Al 2 O 3 -TiC ceramic thin plates with metal bond thin diamond wheels. The warp of the cut-part as well as the flatness of work surface, i.e. deflection of wheel, was precisely measured and thus, the warp generation mechanism was analyzed and the optimum slicing condition was investigated. Grinding forces were measured for discussing the warp. Also, the effect of V-shaped guide groove for depressing the deflection was studied. It is evident that the warp of workpiece and the wheel deflection largely depend on grinding type and pre-processing conditions. The high feed cut-off grinding is most effective for restraining the deflection, and the use of a V-shaped groove is a useful way to depress the deflection
Properties of a monopivot centrifugal blood pump manufactured by 3D printing
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.