Papers by Author: Jun Cheng

Abstract: Micro-grinding is an important processing method in micro-manufacturing field. The influence factors of surface quality in micro-grinding are discussed in the article. The models of finite element analysis (FEA) in micro-grinding H62 with electroplated CBN micro-grinding tool were established. The influence of different grinding factors on the surface quality of the work-piece was discussed by FEA. Different grains sizes were considered to reveal the influence rules on surface roughness in grinding experiments. The results show that the surface roughness decreases with the decreasing of the feed speed and the increasing of the grinding speed. A better surface quality can be achieved with smaller grains sizes. The minimum surface roughness can reach 481nm in side grinding H62.

Abstract: Micro-grinding is an important processing method in micro-manufacturing field. A series of micro-grinding experiments were done with several kinds of commonly used metal materials in the paper, and the influence of different grinding factors on the surface quality of the work-piece was discussed. The surface roughness and surface microstructure of each material were analyzed in micro-grinding. The general developmental law of the surface roughness in micro-grinding was got with different grinding parameters. The surface roughness model proposed by is accurately confirmed according to the experimental results. It provides significant results for the quality of micro-grinding and intense research for the development of micro-grinding.

Abstract: There is a vitrified bond CBN point grinding wheel with coarse grinding area slope angle θ. This new grinding wheel has higher removing rate and better machining accuracy than conventional wheels. The design and manufacture principle of the new grinding wheels are studied in this paper. These wheels with different coarse grinding area slope angle θ are used to grind the stepped shaft of QT700 with a series of grinding parameters.VHX-1000E microscopic system and Micromeasure system are used to measure the surface quality of workpiece. In the same group of grinding parameters, compare the effect of these different wheels on surface roughness. The effect of deflection angle α on surface roughness is generalized.

Abstract: The thermocouple temperature measurement method was adopted to measure the surface temperature in micro-grinding experiment. According to the different grinding depth, the appropriate processing parameters were chosen to find out the temperature field distribution on the surface and in different depth of subsurface. It provided a reference basis in order to prevent the grinding burn. It proves that the method combining the finite element theory with experiment method is correct and feasible. It is a basis of the factors of the grinding temperature and surface integrity of the parts. Further more, it is of great significance that grinding mechanism and surface quality improving of the parts be discussed thoroughly.

Abstract: Micro mechanical processing is the effective method for machining micro scale parts. Micro mill-grinding technology is presented based on micro milling and micro grinding processes. The machining principle of micro mill-grinding is studied, and compound tools for micro mill-grinding are fabricated based on spraying technology. Experiments are performed on Al 6061-T6 with the three-dimensional micro machining system. The results show that submicron surface roughness can be obtained by micro mill-grinding. Abrasive grains of mill-grinding tools fabricated by spraying method shed easily. Smaller abrasive particle size improves the surface quality and increases the tool life.

Abstract: This paper presents a micro-grinding experiment on soda-lime glass to study the surface quality effective factors during micro grinding on hard brittle materials. The process of micro-grinding on soda-lime glass is showed in this paper and micro-grinding equipments are designed, fz(feed rate), ap (grinding depth), vg(Grinding speed) in micro-grinding brittle materials and their effects to surface quality have been discussed by experiments which were carried out on a desktop micro machine developed by NEU. Results proved that fz is the most important factor to the surface quality, and low surface roughness could be achieved by high vg and low fz in micro-grinding soda-lime glass.

Abstract: This paper presents a novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, and a micro-grinding experiment is carried out to study micro grinding principle of the fabricated tools. The manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness accomplished in the experiment is about 0.086μm.

Abstract: This paper presents a micro-grinding experiment on AISI 1020 steel to study micro grinding principle. A novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, the manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness of AISI 1020 steel accomplished in the experiment is about 0.086 μm.

Abstract: This paper presents a novel model of lay out of cutter head of TBM(tunnel boring machine). Rock-broken mechanism during the operation of the cutter head is analyzed to study the layout of cutters. A model of the cutters under the action of forces during TBM’s working has therefore been developed, thus proposing a scheme to improve the rock breakability of TBM’s cutter head on which the cutters are lay out. Then, a nonlinear multi-objective mathematical model with complex constraints is developed, with an optimization program provided via an intelligent algorithm for the layout design of cutters on the cutter head of a TBM. The cutter head of an EPB6.28 TBM, an optimized design is given to set up a prototype with digitized cutter head, to which a simulation is done for the verification of equilibrium of forces. Comparing analytically the cutter wear and equilibrium of forces between a previous and a newly designed cutter heads, the results shows digitally that the new one is more practicable than the previous one.

Abstract: This study presents a practical requirement and realizes one new virtual construction interactive system for tunnel boring machine. One type of TBM(tunnel boring machine)’s virtual prototype has been built. Software PROE is used to build the shield machine model. Application program of virtual assembly system base on virtual reality is developed by using Division, The author also study on key technologies of constructing virtual assembly system of shield machine, such as interference detection in virtual environment. Application program of virtual simulation system base on virtual reality is developed by using C++. The result shows that the work station can be simulated well, and this virtual simulation system can be extended in virtual training and manipulation, virtual construction and so on.