Papers by Author: Xian Li Liu

Abstract: Based on actual working condition, this paper takes the mold materials Cr12MoVwhich is widely used in car cover as research object, and uses the finite element software Deform 3D to establish three-dimensional finite element simulation model of milling hardened steel Cr12MoV process. Reliable material model, chip separation criterion and appropriate boundary conditions are applied. The finite element simulation of milling hardened steel is built with different tilt angles. Milling force of simulation results are verified through experiments.Changes in the milling force with tilt angle are discussed, which can provide certain reference for cutting parameters optimization of milling process and 3D finite element modelling in milling.

Abstract: This paper focus on automobile panel dies and moulds, studying the sliding friction phenomenon between tools and workpiece caused by inadequate margin adopted during finishing. Based on this, the forecasting model of the limit milling depth is built with the consideration of tool deformation. Further on, the model built is tested by milling experiments with different radii of curvature, and providing the evidence for adoption and optimization of margin of steel finishing.

Abstract: In traditional model of high-speed cutting, each modeling or modify process, material parameters input, boundary conditions set take up a lot of time, the solution process has blindness and not easy to operate. this article uses the python language, based on ABAQUS to secondary development of cutting simulation model in pre-treatment, establish exclusive two-dimensional cutting simulation interface, realization the parametric settings of tool angle, the size of the tool and the workpiece, cutting parameters, parametric design can shorten the time of modeling, and lay the foundation for the establishment of the high efficiency and high accuracy of the simulation model.

Abstract: In this paper, a new kind of ellipsoid end mill is proposed in order to improve the quality and efficiency in machining the sculptured surface. An integral ellipsoid end mill parameter optimization system architecture is developed to make the parametric design automatically and efficiently. Then, the mathematical model of continuous blade curve with constant helix angle and normal helix cutting edge of ellipsoid end mill is presented, as well as the cutting edge on the cylinder of cylindrical ellipsoid end mill. And then, all curves are simulated based on MATLAB software. Finally, the ellipsoid end mill is manufactured using a SAACKE UWIF CNC grinding machine to verify the feasibility of ellipsoid end mill.

Abstract: High speed cutting technology has become one of the most important technology in manufacturing of automobile panel dies. The range of each motion axis of numerical control equipment is large and the entire process system exist certain differences of the dynamic characteristic cause of the large type surface size of automobile panel dies. And affect the stability of the processing conditions directly. In this paper, different locations dynamics of large CNC machining equipment was analysed, then getting the influence of processing on the dynamics of the processing position. Simulation results show the machine dynamic characteristic mainly affected by the working position of the spindle box, and the location of the workbench has smaller impact. In the low speed mode, the stiffness characteristics of the spindle box in the operating position on both sides is better and in the high-speed mode the stiffness characteristics is better in the right side of the spindle box. When the table near the right end position in X, Y have weak stiffness near 90Hz.It has weak stiffness in the left side of table near 80Hz and in middle position it has weak stiffness near 80Hz or 140Hz . In the cutting process to provide guidance for the selection of appropriate processing location and process parameters.

Abstract: Take commonly used materials Cr12MoV for automobile panel mold as object of study, using the finite element simulation software ABAQUS, take the node displacement direction as the criterion of the chip formation, determine the minimum cutting thickness of Cr12MoV materials under different tool edge radius values, this value is determined to selection and optimization of mold steel milling finishing machining allowance provides a theoretical basis.

Abstract: Today’s cutting tool, characterized by specialization trend, require flexibility, adaptive and integrating of the cutting tool design. Targeting those goals, this paper presents a new approach, cutting tool “shape-performance-application” integrating design (CTSPAID), which considers the tool shape, performance and applications together, and builds the relationships between them, and achieve the combines between cutting tools and their applications. Also, the system architecture with three layers and two steps is put forward and IDEF0 are selected as the modelling method, as well as some rulers for this system.

Abstract: Hard cutting process is easy to produce serrated chip. Hardened steel GCr15 as the object for the study, chip morphology was studied on hard cutting test and chip cross-sectional microscopic analysis methods. The boundaries of ribbon cuttings to serrated chips cutting was determined, under certain conditions of PCBN cutting tool cutting precision hardened steel GCr15, and form a quantitative description of the chip. With the increase in the amount of cutting, serrated chips have the degree of improved trend, in which the most significant impact of cutting speed, while the hardness increases, the degree of sawtooth also increases. Hard cutting research will enrich the theory provides a theoretical basis for the choice of cutting parameters.

Abstract: Dynamic cutting force will induce vibrations in hardened steel precision turning process. The dynamic cutting force in the process of turning was studied, and the dynamic cutting force model of hardened steel precision turning system was set; Based on DEFORM-3D software, a three-dimensional model of hardened steel turning was established by pre-set some fluctuations workpiece geometry; the turning test of hardened steel GCr15 in CAK6150DI lathe by using PCBN cutting tools, simulation and experimental results show that the high-speed precision turning will produce strip and sawtooth chip morphology; the maximum cutting force of hardened steel precision turning is the radial cutting force, which is greater than the main cutting force; cutting forces have a larger amount of fluctuation, which can reach 30% -55%. This research will provide a theoretical basis for related study on the vibration of the hardened steel turning process

Abstract: The flutter in the hard cutting has a significant impact on the efficiency of production, the quality processed, the environment in processing, the cost, and the life of the machines and tools . However, the application of the method named numerical simulation in MatLab predicted the stability limitation of the hard cutting system, analyzed the influence of cutting system dynamics parameters on the stability limitation of system, at the same time, an experimental verification of hard cutting had been carried out. And the results of analysis showed that improving the system stiffness K and cutting system damping ratio ζ, cutting the stiffness coefficient K_c and the direction coefficient , adjusting the cutting speed to the correct, reducing the amount of turning a_p, decreasing the tip radius of circular arc , increasing the feeding f can be used as the methods of vibration reducing in the system. So the results of the research provide reference for the reasonable choice of cutting parameters.