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Storchak M.,University of Stuttgart | Jiang L.,Changhe Aircraft Industries Group Co. | Xu Y.,Changhe Aircraft Industries Group Co. | Li X.,Beihang University
Production Engineering | Year: 2016

By producing of critical components in the aerospace industry is widely used the β-titanium alloy Ti10V2Fe3Al (Ti-1023) due to its extremely high ratio of strength to density, its great resistance to fatigue, its excellent resistance to corrosion and fracture toughness. This material is characterized by significant difficulties in machining. Substantial assistance in the study of the titanium alloy Ti-1023 machinability can provide a simulation of machining by numerical modeling. This paper presents the results regarding the creation of the FEM models for the cutting processes of the titanium alloy Ti-1023. The created FEM cutting models were constantly verified with experimental tests of the kinetic machining characteristics and analyses of the chip morphology by orthogonal and oblique cutting as well as flat end milling with different depths of immersion. A Johnson–Cook model was used as material model of the workpiece and the damage mechanism of the workpiece is reproduced with the Cocroft and Latham model. The parameters of material and fracture model were determined by DOE study. Comparing the experimentally established and the simulated kinetic machining characteristics and chip morphology confirms that the created FEM models are of a good quality. The size of error for simulating the chip dimensions does not exceed 10 % and ranges between 10 and 30 % for simulating the resultant forces. © 2016 German Academic Society for Production Engineering (WGP) Source


He Y.,Beihang University | Chen Z.,Beihang University | Wu X.,Changhe Aircraft Industries Group Co.
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014

The iso-parametric method is widely used for the tool path generation of sculptured surface machining. Traditional methods for calculating path intervals can't ensure accuracy in wide strip machining. A path interval prediction and adjustment method is developed to avoid undercut or excessive overlap between adjacent tool paths. With this method, the subsequent tool path driving lines can be predicted from the existing tool paths. Then, effective overlap interval is constructed, and several characteristic tool positions are selected to represent the whole path. Finally, the driving line is adjusted until the machining verge of the selected tool positions fall in the effective overlap interval. The effective overlap interval provides basis for defining path interval, and the calculation burden of adjusting the driving line is greatly reduced by selecting the characteristic tool positions. A calculation example shows that the proposed method can achieve accurate overlap between adjacent tool paths. Source


Xu R.,Shandong University of Technology | Xu R.,Beihang University | Xu R.,Changhe Aircraft Industries Group Co. | Chen Z.,Beihang University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2014

In order to solve the problem of tool radius compensation in five-axis machining for the CNC systems without the function of five-axis tool radius compensation, a method of five-axis tool radius compensation based on post-processor is proposed. First, the basic principle of five-axis tool radius compensation is investigated. For three types of cutters (i. e. ball-end cutter, flat-end cutter, and torus cutter), tool radius compensation direction and vector equation of compensated cutter location (CL) point are derived, respectively. Second, a five-axis CNC machine tool with rotary head and table is used as an example. In terms of the relation equation between CL data and machine control data and vector equation of compensated CL point, a relation equation between compensated CL data and machine control data will be obtained. Then, a post-processing software with the function of five-axis tool radius compensation is developed using Visual C++ 6.0. And the post-processing software not only generates the compensated CNC program directly, but also generates the CNC program with macro variables of tool radius compensation. Finally, an aero blade surface is machined, and the machining process is simulated by using VERICUT software. Simulated results verify the correctness and effectiveness of the proposed method. Accordingly, the proposed method can easily implement the function of tool radius compensation for the CNC systems without the function of five-axis tool radius compensation, and avoid the complicated process that when the cutter radius changes, the programmer must return to CAM system to generate new tool paths and post-process CL data again. Further, the proposed method can shorten the total machining time of parts and enhance the reusability of CNC program, and will be widely applied in practice. © 2014 Journal of Mechanical Engineering. Source


Zhou Z.,Beihang University | Chen Z.,Beihang University | Xiong X.,Changhe Aircraft Industries Group Co. | Xu Y.,Changhe Aircraft Industries Group Co.
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2014

The surface integrity (surface topography, surface roughness, work hardening) of TB6 after side milling was studied based on the minimum data set. The results show that it's the feed engagement (fz) that influences the surface topography most and high fz may cause scale on the milled surface. fz is the main reason that influences the roughness of feed direction. The surface roughness (Ra) raised from 0.283 μm to 0.964 μm with fz increased from 0.06 mm/z to 0.12 mm/z. The milling parameters (vc, fz, ae) have no apparent influence on the roughness perpendicular to the feed direction while the flank wear (VB) influences it a lot. With the VB raised from 0 to 0.025 mm, the roughness perpendicular to the feed direction increased from 0.22 μm to 0.686 μm. There is no apparent work hardening or surface degenerating layer appeared during the side milling process of TB6. Source


Xu R.,Shandong University of Technology | Xu R.,Beihang University | Xu R.,Changhe Aircraft Industries Group Co. | Chen Z.,Beihang University | And 3 more authors.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2015

In order to solve the problem of the poor machining quality of the leading and trailing edge surface of the aero engine blade, a tool orientation optimization method based on the kinematics constraints of the machine tool in multi-axis machining with a ball-end cutter is presented. A relation equation between the design variables of tool position and cutter location (CL) data is established, and a coordinate transformation equation between CL data and rotary axes of the machine tool is established. From the above two equations, a relation equation between the design variables of tool position and rotary axes of the machine tool is derived. Through solving the above relation equation, formulas for calculating tool position and tool orientation during the machining of sculptured surfaces with a ball-end cutter are derived. On this basis, a tool orientation optimization method and a tool path generation method for multi-axis machining with a ball-end cutter is presented. Besides, analyze the influence of the proposed method and Sturz method on rotary axes of the machine tool. Tool paths of the leading edge surface of an aero engine blade are generated by the proposed method and the Sturz method, respectively, and cutting trials are carried out on a five-axis machine tool. Experimental results show that the proposed method can avoid abrupt change of rotary axes of the machine tool and make the movement of machine axes more stable and smoother, and further obtain better machining quality and higher machining efficiency. Consequently, the proposed method will have important practical value. © 2015 Journal of Mechanical Engineering. Source

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