Key Engineering Materials Vol. 522

Abstract: mprovements in modeling and simulation of metal cutting processes are required in advanced manufacturing technologies. A three dimensional fully thermal mechanical coupled finite element model had been applied to simulate and analyze the cutting temperature for high speed milling of TiAl6V4 titanium alloy. The temperature distribution induced in the tool and the workpiece was predicted. The effects of the milling speed and radial depth of cut on the maximum cutting temperature in the tool was investigated. The results show that only a rising of temperature in the lamella of the machined surface is influenced by the milling heat. The maximum temperature in the tool increases with increasing radial depth of cut and milling speed which value is 310°C at a speed of 60 m/min and increases to 740°C at 400m/min. The maximum temperature is only effective on a concentrated area at the cutting edge and the location of the maximum temperature moves away from the tool tip for higher radial depths of milling. The predicted temperature distribution during the cutting process is consistent with the experimental results given in the literature. The results obtained from this study provide a fundamental understanding the process mechanics of HSM of TiAl6V4 titanium alloys.

Abstract: We make a design of the block diagram of the guard fastening holes processing in this paper. It introduces the car doors composition and functional requirements, uses workbench to analysis the rack to determine its legitimacy. This design not only greatly improved the production efficiency of the car guard fastening hole machining, but also improve design standards and safety of the machine by model simulation analysis.

Abstract: Based on metal cutting theory and the key technology of finite element simulation, this paper uses finite element software Deform to establish three-dimensional finite element simulation model and simulate cutting process. This paper uses the work piece material is IN718 high temperature alloys packaged in Deform, and analyzes the processing characteristics of high temperature, choosing the right tools and cutting dosages to simulate. Through the simulation we can get scraps forming process, the surface stress, strain, temperature and cutting force distribution of the workpiece and the tool. We can also get the change rule of cutting force and cutting temperature under the different cutting parameters. The simulation results provide the theoretical basis for the optimization of cutting parameter selection in production practice.

Abstract: In this paper studies the effect of the temperature of boronized layer, holding time and formula of accelerant on the microstructure and properties boronized layer. The result shows that the thickness of boronized layer increases with the increasing of temperature of boronized layer and the holding time expansion. In the experiment, the research contrasts the effect of five groups of boron-sulphurizing rare earths co-cementation and finds that the best effect is to add 1.5% sulfide and 5% rare earth in reagent. The metallographic analysis and hardness testing show that the properties of boronized layer have improved evidently.

Abstract: In the process of vacuum casting, non-uniform flow front velocity about pouring material will lead to casting non-uniform shrinkage and warping deformation. Ideal filling pattern should make pouring material fill into the mold cavity with uniform flow front velocity. Give an optimization method of vacuum casting process, optimize the filling velocity in the filling process by combining numerical simulation and optimization method, and make the flow front velocity of pouring material uniform in the filling process, further reduce the warping deformation of casting. The example shows that the optimal model and the given solution algorithm is feasible.

Abstract: There is a great attention to the usage rate of Al-Cu alloys due to the largely use of Al-5%Cu based alloys in the aerospace industry in the past decades. The improvement of microstructure and properties of Al-5%Cu based alloy by refinement and modification. Specially, the refinement and modification of Al-Cu alloy can be achieved by addition of rare earth. In this paper, the effect of Y on the microstructure and properties of Al-5%Cu based alloy was investigated. The results show that θ (Al₂Cu) phases change from mesh structure into fish-bone shape and grains are refined. Y additions promoted the end-solidification temperature and decreased the quantity of eutectic in grain boundaries, and narrowed the crystallization range and increased the hot-tearing resistance and decreased the hot-tearing susceptibility significantly.

Abstract: The machining efficiency of titanium alloy Ti6Al4V is low and the tool wear is serious. In this paper, uncoated carbide tool and two kinds of coated cemented carbide tool were used for dry turning titanium alloy. The experiments used CCD Observing System and the EDAX analysis of SEM to study tool wear mechanism and analyze the cutting performance through tool life, cutting force and cutting temperature. The results show that the main wear reasons are adhesion, diffusion and oxidation wear. For coated tool, the coating peeled off first, and then tool substrate damaged. Compared with coated carbide tool, the uncoated carbide tool with fine grain has longer tool life and lower cutting force and cutting temperature. The changes of cutting force and cutting temperature with cutting speed are not obvious when using the ccomposite coating (TiAlN and AlCrN) carbide tool. The results can help to choose tool material reasonably and control tool wear.

Abstract: An experimental study of grinding force in microgrinding zirconia ceramics using small grinding tool is presented. In the experiments, the grinding tool used is electroplated diamond microgrinding wheels of 0.41, 0.63 and 0.76 μm in diameter, and the machining operations were conducted in side grinding under dry cutting. The process parameters include the diameter of the microgrinding wheel, feedrate, and rotational speed of the grinding spindle. The microgrinding forces were measured by a Kistler three-component dynamometer. The experimental results show that the normal forces are much larger than the tangential forces, the effects of process parameters selected on the variation of experimental results is almost the same for tangential forces, and that is the feedrate, diameter of the microgrinding wheel and rotational speed of the grinding spindle in turn for normal forces. As the feedrate increases or diameter of the wheel increases, the microgrinding forces increase, and the magnitudes of increase are more significant at higher radial grinding depth.

Abstract: Dry cutting technology is a new environmentally friendly green process technology. Based on the characteristics of dry cutting and deep-hole processing, a deep-hole processing solution by means of dry cutting technology is presented, that is the near-dry deep hole processing system. Combination of the characteristics of near-dry deep hole processing, we improve the design of tool structure and the selection of blade material, and find the blade material of near-dry deep hole processing by processing testing. Analyzing and testing the cutting performance and processing effect by comparing near-dry and traditional oil processing methods, we achieve a satisfactory result and confirm that the near-dry processing is a green processing technology which has a good processing effect and applying prospect.

Abstract: There are lots of titanium alloy parts which have large-scale micro-structures in astronautic structure and medical implants, so the micro milling becomes one of the effective processing methods in getting the surface micro-structure. Because the titanium alloy has high caking property in processing, it needs a research on the cutting heat and force in order to get better machining precision and surface quality. According to the finite element theory in elastic and plasticity, the influence of cutting speed to the cutting heat and force is got by finite element simulation analysis to the titanium material TC4 in cutting process. It can get the simulation results of cutting heat and force in the micro milling processing by finite element analysis, and then compared, the basic influence which the cutting speed to the cutting heat and force is got. The correctness of the result is checked through cutting experiments.