Papers by Author: Yan Li

Abstract: The graphite-like carbon (GLC) coating was deposited onto high-speed steel (HSS) twist drills by magnetron sputter ion plating technique. The drilling tests were performed on the ferrous metal under dry cutting conditions. By the analysis and comparison of the flank wear and the drilling forces on drills, the cutting performance of GLC coated HSS tools was researched. The results show that GLC coating with high hardness and low friction coefficient, due to its good adhesion and match with HSS substrate, can significantly improve the cutting performance of HSS twist drills, prolong the tool life, decrease the drilling forces in drilling the ferrous metal. And its cutting performance is better than the hard coated drills in the lower speed, but its thermal stability is inferior to the hard coated drills in the higher speed.

Abstract: The Shape from Shading (SFS) method is adopted to detect the micro-topography and roughness parameter of machining surface based on computer micro-vision in this paper. According to the reflection features of micro metal surface, the illumination model is improved by the weighting superposition of the diffuse component of the simplified Oren-Nayar model and the specular component of the Torrance-Sparrow model. The minimized calculation method of SFS is given based on the improved illumination model. The 3D topography reconstruction and the roughness parameter detection of the turning surface are accomplished. The experimental results show that this method can rapidly realize the accurate detection of surface roughness parameter, and provides new ideas and methods for detection the roughness on-line in machining process.

Abstract: Lead screw high-speed cold roll-beating is a new single-point incremental forming technology which is die-free and unconstrained. The principle of the forming process is analyzed. Modeling, meshing and parameter selecting for forming process simulation with ABAQUS are discussed. The lead screw cold roll-beating forming process simulation is carried out; stress & strain changes and metal flowing law are analyzed. Experiments are carried out with the self-developed experimental equipment. The experimental results are consistent with the simulation results, thus the validity of the simulation and feasibility of the forming process are verified.

Abstract: Establishing effective network manufacturing alliance is the top priority of carrying out network manufacturing. Under circumstance of realizing resource sharing in network manufacturing, a method of network manufacturing alliance establishing based on service resource matching is put forward. Based on model of resource description framework, manufacturing service resource description model and matching strategy are established. According to describing feature of resource properties, matching of manufacturing resource and service resource is further transferred into corresponding qualitative and quantitative matching, similarity measuring methods of qualitative and quantitative properties in the matching process are presented respectively so as to accurately evaluate matching degree between manufacturing resource and service request. Availability of the model and its matching algorithm is verified by means of practical instances.

Abstract: The high-speed cold roll-beating technology is adopted to realize the single-point accumulation forming of involute spline. Firstly, the principle of the forming technology is analyzed. Then the FEA model of the cold roll-beating of involute spline is built, the forming process simulation is finished with the ANSYS/LS-DYNA software to obtain the stress, strain and the metal flowing law of the forming process. Finally the experiments are carried out to verify the feasibility of the simulative results. This study can provide guidance for further study of the forming mechanism and practical application of the single-point accumulation forming technology.

Abstract: The experiment that WXD170-type reciprocating rotating diamond wire saw cuts SiC wafer was studied using orthogonal test method in this paper. The influence of cutting speed of diamond wire saw, work-piece feed speed and rotating speed of work-piece on cutting process were analyzed. The optimized cutting parameters which can improve surface quality of slices and reduce tangential force were obtained. The results show that: the surface quality of slices which was cloud-shaped can be improved significantly due to the increase of the work-piece rotation. The work-piece feed speed and the rotation speed have greater impact on the tangential force than the saw wire speed; the work-piece feed speed and the work-piece rotation speed have greater impact on surface roughness than the saw wire speed. An important way to be obtained the smaller tangential force and better surface quality of slices is considering of a reasonable match among cutting speed of diamond wire saw, work-piece feed speed and rotating speed of work-piece comprehensively.

Abstract: To optimize the process parameters of cold rolling the finite element model of metal plastic flow in cold rolling was carried out based on the cold forming principle of ballscrew and rigid-plastic finite element theory. The adaptive mesh refinement was utilized to improve calculation accuracy in large plastic deformation zone. Using lagrangian algorithm the processing of cold rolling is numerically simulated by DEFORM-3D. The appropriate revolution speed is got by analyzing different simulation results such as the maximum stress and maximum strain and flow velocity etc. under different revolution speeds. The appropriate transmission ratio is got by analyzing different simulation results such as the maximum stress and maximum strain and flow velocity etc. under different transmission ratios. The research results provide evidence for process parameters optimization. At the same time those research results lay a foundation of further study of forming mechanism.

Abstract: 6σ has proved numerous times that it can help any business to deliver products to meet or even exceed customer expectations. DMAIC (Define – Measure – Analyze – Improve - Control) is one of the Six Sigma methodologies used for a 6σ project that aims to improve and control quality of exiting products. Aiming at the drawbacks existed in the problem selection in definition stage, considering the fuzziness and uncertainty of problem analyzing, a method integrating fuzzy QFD (Quality Function Deployment), frequency-cost FMEA (Failure Mode Effect Analysis) and gray relation analysis is presented, in which the customer requirements, occurring frequencies and the relative costs of the problems are taken into account comprehensively. Thus the key quality characteristics or process features to be improved are determined, which can provide decision support for key problem selection. An example is given to illustrate the effectiveness of the proposed method.

Abstract: The basic principle of three-dimensional surface roughness laser triangulation has been analyzed in this paper, Light-path diagram and optical geometric relationship of direct-type and symmetric oblique-type triangulation measurement is studied, the mathematical model of Surface micro-height information analysis is given. Resolution of direct-type and symmetric oblique-type triangulation measurement is compared both qualitatively and quantitatively. At last, the Application of laser triangulation method in Three-dimensional surface roughness measurement is analyzed.

Abstract: According to the kinematics theory of part surface forming motion and engagement principle, shaping movement of ballscrew manufactured by cold rolling has been investigated. The motion relationship and mathematical model of ballscrew have been built. By means of ADAMS and MATLAB the motion simulation and numerical calculation of cold rolling have been done. From analysis results, motion relationships between roller and workpiece and forming principle of cold rolling have been revealed. These studies will provide quantitative basis for technologic research of cold rolling and promote the study of ballscrew’s cold rolling forming mechanism.