Materials Science Forum Vols. 800-801

Abstract: Laser assisted milling(LAM) can change the cutting processability of the workpiece, which is evaluated by the temperature of cutting zone. Therefore, the prediction of cutting zone temperature in LAM has an important practical meaning. There is a kind of complicated nonlinear relation between the cutting zone temperature and its adjacent temperature. Meanwhile the BP neural network (BP NN)can truly elaborate the nonlinear relation. In this paper, a new kind of algorithm combined the advantages of genetic algorithm (GA) and BP neural network is introduced to predict the temperature correctly. GA is used to train connection weights and biases of BP neural network. According to the characteristics of cutting area temperature distribution, the adjacent temperature and time are selected as the judging indexes. Then the model of predicting the cutting zone temperature is built. Practical application reveals that the model is a very efficient method.

Abstract: Fir tree groove broaching rebound has an obvious impact on the wheel groove manufacturing accuracy. The prediction of wheel groove rebound in the broaching process is an important aspect to improve the manufacturing precision of wheel groove. The deformation caused by cutting force is the main factor that decides wheel groove broaching deformation. For the problem of tree wheel groove broaching deformation and rebound: Firstly, calculating the actual cutting force through experiment and empirical formula of cutting unit cutting force, and then loading the cutting force as the initial load in the wheel groove line; Secondly, using the finite element software-Abaqus to copy the analysis of the wheel groove in the broaching process; Finally, comparing the rebound deformation curve and the data generated by the simulation with the actual ones measured by the worked wheel groove, and the result of simulation is consistent with the rebound. The prediction of wheel groove broaching rebound provides the basic theory to improve the wheel groove broaching of rebound problem.

Abstract: Cutting force equation was established for milling with flat end cutter as feeding in straight-line path by means of discretization method. The model of milling force was conducted based on the manufacturing character of cylindrical surface. The milling force is continual change in manufacturing process, it’s not only influenced by milling parameter, but also related with the shape of cam’s contour. Milling force can result in vibration as machining. Milling force prediction is very useful for manufacturing accuracy control.

Abstract: Application prospect of the high volume fraction SiCp/Al composites becomes increasingly widespread, the study of cutting mechanism is important for achieving its high efficient and precision machining. In this paper, a three-dimensional beveled simulation model of high volume fraction SiCp/Al composites on high-speed milling is established by finite element software ABAQUS, the constitutive on model material, the tool-chip contact and the chip separation model is elected reasonably.The paper analyzes the effect of cutting speed on the chip formation and the stress distribution of the material. The results shows that: with the increasing of cutting speed, the chip is easily broken, cutting speed have little impact on the maximum stress of the material.

Abstract: The process parameter prediction and analysis of high-speed NC machining of cast aluminum combination framework is one of the important research directions of mechanical processing. In order to make sure predicting the high-speed NC machining parameters of cast aluminum framework while machining、improve production efficiency、reduce the requirement for machine tool accuracy and technology level of operating personnel, established high-speed NC machining system time forecast model of combination framework applying BP neural network, doing corresponding verification of high-speed NC machining process parameters, then designed a set of process suitable for cast aluminum combination framework high-speed NC machining, providing feasible solution for high precision machining.

Abstract: High-temperature alloy can easily produce jagged chips in high-speed cutting conditions. The serrated chips will lead to the volatility of cutting force and impact the processing efficiency and quality. The formation mechanism of serrated chip has important significance to improve processing quality and efficiency. As the serrated chips have very short generation time, it is very hard to measure the changes of the stress, strain and temperature during the formation of serrated chips in experimental method. And it is more difficult to carry out quantitative and qualitative analysis. So it has been the research priorities and difficulties in the field of metal cutting. In this paper, both the finite element method simulation and experimental method are used to study the formation mechanism of serrated chip, deformation of material and the degree of variation of jagged. It has an important reference value to select cutting parameters for high-temperature alloy cutting.

Abstract: The research focused on the finite element simulation of the surface residual stress and took an experiment to get cutting temperature and cutting force by changing different groove and coated tools. Then it analyzed the influence of cutting and tool parameters on cutting force and temperature. Finally, the results reached a conclusion about the way that the tools with different groove and coating influenced the residual stress. The coated tools reduced the residual tensile stress in the machined surface. The axial and tangential residual stress was tensile stress and the tangential residual stress was larger than the axial in machining.

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: In this paper, numerical simulation method is used to study the turning tool strength by Deform 3D in the process of rough machining high strength steel (2.25Cr-1Mo-0.25V).It mainly studies the effect of the feed rate on the cutting force. At the same time, non-uniform distribution cutting force got from the simulation results is taken as the numerical simulation mechanical load of turning tool blade strength to study the influence of feed rate on the turning tool strength. The simulation results show that: with the feed increasing, the mechanical load that turning tool blade bears increases. The maximum effective stress and displacement of the turning tool blade is also increased.

Abstract: SiC_p/Al composites (aluminum alloys reinforced with SiC particles) are classified as the typical difficult-to-machine materials by serious tool wear, premature tool failure, surface defects, etc. In order to understand the formation mechanism of chip and machined surface, the two-dimensional finite element modeling technology of the cutting process for SiC_p/Al composites are investigated by using ABAQUS explicit. The actual microstructure is modeled by a multi-phase modeling approach with a circular SiC reinforcement phase randomly distributed in a 6061aluminum alloy matrix phase. The effect of volume fraction of SiC particles is studied by simulating the orthogonal cutting process of aluminum alloy and three SiC_p/Al composites with multiplied increasing volume fraction of SiC reinforcement particles. The cutting forces vs. time due to the interaction between cutting tools and SiC particles in the cutting process and the stress distribution in three deformation zones are analyzed. Finally, surface defects including particles debonding, small pits, raised particles and traces of ploughing are predicted and verified by the experimental surface topography.