Advances in Materials Manufacturing Science and Technology II

Abstract: Polishing with Flotative Abrasive Balls(FABs) is a kind of soft contact polishing means， and the conventional polishing plate and pad are not needed in this case. The pressure of polishing is the flotage which is the upward force that a fluid exerts on the FABs, but the movement of work piece is similar to that in conventional polishing, the removal rate and quality of polishing is influenced by FAB and its flotage. An experiment device is built up and two kinds of FAB are designed and produced. Some primary experiments are carried out in order to investigate the influences of the size of FABs on the removal rate and surface roughness in polishing with FABs. It is found from the experiments that the grain size and the layers of FAB may have great influence on the removal rate of polishing; the surface roughness is mainly decided by the ball diameter and the layers of FAB. The results of experiments are discussed and analyzed, it indicates that the efficiency and quality depend on flotage and the number of active grains when the velocity of workpiece is assigned.

Abstract: The saw tooth grooves of blazed grating ruled by ruling engine are formed by diamond tool which presses on the aluminum film evaporated on the substrate of optical glass or metal. The real shape of ruled saw tooth groove is different from that of the ideal groove and the ruling process indicates that there are the zero order planes, similar to the flat tops, on the grating grooves. The results of Fourier analysis for the real ruled grating featuring the zero order plane structure shows that the flat top width is an important factor for grating efficiency. Additionally, bigger pressure value loaded on the diamond tool and bigger lateral pressure value on the aluminum film will be benefit to the improvement of grating diffraction efficiency. Based on the grating interferometer, the high precision positioning control system of ruling engine guarantees the accuracy of the grooves space. High density blazed grating whose space is 0.83μm is manufactured and its’ grooves spaces are very equidistant and uniform under the view field of AFM. And the infrared blazed grating, whose diffraction efficiency in the first order is up to 97 percent, is ruled successfully also.

Abstract: This research utilizes an image-vision-system to measure the size of the product-burr. The relational expression was established between the clearance of micro punching die and burr size after blanking the composite material via a neural network. This can help to anticipate the burr size under any clearance and used cycles of punching die. The purposes of this research are: (1) it can predict the used cycles of punching die at any clearance between the punch and die, the engineer can change the punching dies at right moment to prevent the bad product from producing; (2) it can utilize this research to find out the optimum clearance condition which can avoid bad design of the punching die, which will take long time to repaired the punching die.

Abstract: This paper carries out grinding efficiency experiments on various formulas composed of long carbon chain alcohol and halogenated hydrocarbons with the first principle of grinding fluid as main evaluating index and finds via infrared spectrum testing that the conjugating ways of lubricating films between alcohol-type grinding fluid and ceramics is based on chemical adsorption or hydrogen bonding adsorption and generates alkoxy silane or polyalkoxy silane with perfect anti-friction action under the condition of grinding high temperature. With adding of halogenated hydrocarbons, it can further make grinding fluid with perfect extreme pressure property and improves grinding efficiency. Furthermore, this dissertation firstly introduces heat capacity as analysis means and discusses the influential factors on the removal rate of ceramics materials when using abovementioned grinding fluid. It is shown from the result that the material removal rate when silicon nitride ceramics grinding will increase with the augmentation of heat capacity.

Abstract: Using Mo powder, B-Fe alloy powder and Fe powder as raw materials, adding Ni and Cr respectively, with proper forming additives, the green body is formed by coining. The ternary boride hard alloy material is fabricated by liquid phase sintering technology. The influence of different content of Cr and Ni on mechanical properties is studied respectively. The optimal content of Cr and Ni and the optimal temperature are found.

Abstract: Through combining turning experiments and FE simulations, this paper studied the effects of force, temperature and residual stress of machined surface on high speed hard turning GCr15 bearing steel hardened to HRC60-62 with three kinds of ordinary edge preparation (sharp-edge, hone and chamfer). The experiment and simulation results indicated that the diathermanous proportion of chamfered edge preparation to tool and machined surface is less, and this distribution of cutting temperatures is useful for tool life and machined surface quality. The simulation results showed that cutting force had a descending tendency with increasing of cutting speed, which is in accordance with the change rules of machining general rigidity material, and it proved that FE simulations have good precision. The simulation results of residual stress of machined surface showed that residual tensile stress existed in machined surface using both honed and chamfered tools, and a highest compressive stress (about -200MPa) existed among 150-200μm of the depth into the workpiece surface. The difference was that the depth of superficial harden layer with honed tools is larger than that with chamfered tools.

Abstract: In the present study, surface roughness after grinding with different mesh size diamond wheels were measured to study the surface roughness characteristics of engineering ceramics. According to the surface behaviours and measured surface roughness, the relation between the surface roughness and the properties of these brittle materials was described. Coupled with the micro-observation of ground surfaces, it was concluded that the grinding condition and material properties led to the differences of surface roughness characteristics of brittle materials. The silicon nitride ceramic was the most easily machined to ductile surface among these ceramics.

Abstract: The scale structure and the experiment equipment are designed on the nano ferrofluidic scale the string axle of the big length to radius, according to the principle of the nano ferrofluidic scale. The experiment study is made on the problems of the scale performance relation associated with this string axle, the rotational speed and the excitation current big or small. The reliability of the nano ferrofluidic scale the string axle of the big length to radius is proved.

Abstract: Rapid prototyping full compacted metal parts has becoming the focus of attention in the domain of rapid prototyping. In this paper, the method of forming full compacted metal parts by selective laser melting has been put out and the experimental researches on it have been carried out. The surface quality and the inner microstructure of the parts formed by selective laser melting were analyzed. The full compacted metal parts without any micro-cracks have been attained. The test results show that the tensile strengthen of 316L stainless steel parts formed by selective laser melting is greater than that of casting 316L stainless steel parts.