Abstract: It is well known that there is a lager deviation in the fatigue life of machined components even under nominally identical loading conditions. Understanding and controlling fatigue life variance are essential to enhance reliability. However, few research focus on the impact of machining processes on the fatigue life variance of machined components. In this study, surface residual stress distributions of bearing rings randomly selected from a production line by super-finishing grinding, are measured by X-ray diffraction method in cutting and feed direction, and its scatter is analyzed by statistical tools. Based on the variance prediction theories, build a simplified fatigue life variance prediction model incorporating the resultant residual stresses scatter induced by machining process. Based on the Basquin equation, the model is validated by experimental data published in literature. The predicted fatigue life agrees well with the experimental average fatigue life. Statistical analysis shows that the predicted variances of fatigue life are equal to those estimated from experimental fatigue life.
Abstract: In ceramic machining field, the ultimate goal is to keep material surface integrity, dimension precision and max material removal rate synchronously. HIPSN ceramic ring high speed grinding experiments and researches have been performed, by testing and analyzing grinding force, combining grinding motorized spindle dynamic performance with grinding surface roughness, the influences on ceramic machining quality have been discussed. The grinding parameter can be chose in precondition promising machining quality. It possesses guidance significance in low cost, high efficiency precise ceramic parts machining.
Abstract: The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives which are developed on the basis of the phase transition phenomenon caused by magnetic field. The rheological effect of FMA is the basis to achieve its finishing function, and has a great impact on the finishing capabilities and the final surface roughness. In order to get a better understanding of FMA finishing mechanism, the rheological effect models of FMA are deduced for the first time, the simulations and the experimental results are discussed as well in this paper.
Abstract: One of the most important challenging problems in modern mechanical manufacture industry is how to reload the repaired tool properly to the numerical machine. An innovation method is put forward considering the above mentioned problem. It takes account of raster sensors due to the characteristics of high accuracy, wide scope of dynamic measurement, non-contact measurement and flexible to automation and numeralization. A measurement system is constructed based on the principle of raster sensors. One operating example of raster provides quite precise results, which would be one of the solutions to the key problem of reloading machine tool.
Abstract: In order to better understand the grinding mechanism, the rough, semi-fine and fine ground silicon wafer subsurface damage models are experimentally investigated with the aid of advanced measurement methods. The results show that the rough ground wafer subsurface damage model is composed of large quantity of microcracks with complicated configurations, high density dislocations, stalk faults and elastic deformation layer. Among them microcracks, dislocations and stalk faults are dominant. Apart from the above damage, the amorphous layer and polycrystalline layer (Si-I, Si-III, Si-IV and Si-XII) exist in the semi-fine ground and fine ground wafer subsurface damage models. The amorphous layer depth firstly increases from rough grinding to semi-fine grinding and then decreases from semi-fine grinding to fine grinding. The damage model can be divided in severe damage part and elastic deformation part with high stress. When the material is removed by ductile mode two parts are all small and the ratio of second part is relatively great.
Abstract: In precision measurement, the existed error of measuring system influences surface accuracy more. This paper provides an error analysis focusing on the research effort on aspheric lens on-machine measurement for form accuracy. And the error parameters including positioning error of coordinate origin, tilt angle and radius error of probe head are investigated. It was known that it was quite difficult to obtain the parameters by detecting instruments, so the method of error separation and correction based on measuring standard parts is presented in this paper to guide the inverse solution for higher measuring accuracy. Also, a measuring experiment with Φ210mm lens is executed. Experimental results indicate that the method based on standard parts is suitable for on-machine precision measuring of aspheric lens.
Abstract: This paper reports on the wheel wear in high speed grinding silicon nitride used metal bond diamond wheels. The investigation focuses on the relation among grinding force, grinding ratio and wheel wear. Experiments have been performed to investigate the factor of wheel wear such as grinding ratio and grinding force. The results of these investigations are presented in this paper. With the application of this technology, a low cost production and high efficiency of ceramic bearing ring grinding can be realized.
Abstract: In this paper, Pulse electrochemical finishing (PECF) and pulse electrochemical compound finishing (PECCF) are introduced. The main technical parameters, including in intereletrode gap, current density, compositions of steel materials and pulse parameters on the resulting surface finish were studied. PECF and PECCF on different surface including plane and shafts surface are done. Well-pleasing experimental results is gained. Results indicate that PECF and PECCF can lead to both good smoothing efficiency and surface finish simultaneity at low costs.
Abstract: To reach high surface integrity and processing efficiency, the semi-fixed abrasive wheel (SFAW) is developed. Compacting process plays key role in adjusting the structure and machining ability of SFAW. In this paper, the manufacturing of SFAW is introduced, and the effect of compacting patterns and process parameters on the structure of SFAW is discussed with experimental results and a developed model based on particle flow method. It is found that the lower compacting velocity result into longer time to achieve a certain compacting force. It needs greater compacting force to achieve a certain compacting density with higher compacting force loading rate. The higher friction factor and contact module of grits result into greater compacting force to achieve a certain compacting density.
Abstract: In order to study the grinding technology of Isometric Polygonal Profile (IPP), NC grinding accessory of IPP is developed, which is driven by Program Logic Controller (PLC) and step-motors. On the basis of the principle of coordinate conversion and envelope curve, formative motions of IPP are discussed in detail. Because the relationship between the rotation of parts and synchronization motion in both x and y axes of coordinates frame is of the proportional transmission, and the synchronization motion is harmonic motion in both x and y axes of coordinates frame, the relationship of them is of the proportional transmission too, but the frequency of the synchronization motion is low and the displacement is small, so the eccentric mechanism is used in the grinding accessory. The grinding process of three axes linkage of IPP can be translated into process of two axes linkage between three coordinates on machine tools by means of combination of PLC and the eccentric mechanism. It has been found by grinding experiment that the NC grinding accessory is available used for grinding IPP and other polygonal profile.