Papers by Keyword: Complex Surface

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Authors: Gao Shan Tan, Li Yan Zhang, Sheng Lan Liu, Qing Lan Shi
Abstract: Different error requirements on different surfaces are necessary in many situations. If the registration between the measured dataset and the nominal surface is performed ignoring these differences, an inaccurate result could occur due to the surfaces which have low precision. An improper registration even results in false verdict. So the differentiated registration is of significance in precision engineering. In this paper, a new registration method taking into consideration of the different error requirements is proposed. Firstly surfaces are classified based on different error requirement. Then, appropriate weight factors are iteratively given to these surfaces. Based on the change relationship of error and weight factors, the algorithm controls the error distribution by optimizing the weighted least squares. Our method has the great flexibility in distributing the error, which is suitable for engineering applications. The experiment demonstrates the validity.
1635
Authors: Hong Jun Liu, Ai Guo Zhang, Ji Bin Zhao, Jin Shang, Jun Liu
Abstract: This paper presents a new strategy of analysis and compensation of non-linear error. Non-linear error is an important source of machining error in multi-axis numerical controlled machining and it is unavoidable. In view of tool positions optimization in five-axis CNC machining of complex surface, this paper presents a strategy for non-linear error compensation in five-axis machining: Firstly, non-linear error caused by the change of tool axis vector is analyzed and the non-linear error model is established, in order to get the maximum non-linear error of interpolation segment; Then, the tool position that meets the machining accuracy is obtained; Finally, Simulation and analysis of the model show that the proposed method is effective and greatly improves the geometric accuracy.
4967
Authors: Xian Zhang Feng, Li Ping Wang, Li Hong Yu, Zhi Qiang Jiang, Liang Ji Chen, Jing Li, Yan Mei Cui
Abstract: Disappearing mould casting is a new accurately processes with nearly free margin and precision forming, in which is no modulus, no parting, no sand core, so the casting without splash, burr and taper angle. It can improve the dimensional accuracy of the core portfolio for complex surface of the key compose of the disappearing mould. It has completed the design and manufacturing of these by the three-dimensional CAD/CAM technology, and obtains a series of effective methods and experience for the development of the products. The researched results have important directive to production practices for the design and machining process for the expendable pattern casting.
1195
Authors: Hui Ying Li, Liang Ji Chen
Abstract: In order to enhance machining precision of complex surfaces with a flat-end cutter, the generating method of cutter contacting (CC) paths is presented in this article. With the method of coordinate transformation, effective machining radius of a flat-end cutter had been deduced and the step-over formed by two adjacent CC paths were implemented. The parameter increment along the CC path interval direction was calculated by using geometric analysis of the local area of CC point. The corresponding NURBS path of tool center points including knot vector and controlling points was obtained from the cutter contacting points.
1630
Authors: Xiong Bing Li, Hong Wei Hu, Ling Li, Lin Jin Tong
Abstract: In this paper, we address the problem of automatic inspection of CFRP with complex surface using an ultrasonic technique. The 3D surface data are obtained by ultrasonic measurement, and then the inspection path is planned after the CAD model has been reconstructed. Defect position and size are figured out by analyzing C-Scan image. Characters of defect type are modeling according to A-wave data. Thereafter, an algorithm based on Multi-SVM is presented to classify defect types which use the energy character of defect dynamic waveform. Finally, application experiments are conducted to verify the validity and superiority of the method proposed in this paper.
297
Authors: Cao Qing Yan, Jun Zhao, Yue En Li, Shi Guo Han
Abstract: Complex surface mold has been widely used in various industries, and high efficiency and high quality can been achieved through high-speed CNC milling processing. Surface roughness including transverse and longitudinal roughness is an important criterion for mold quality. A high-speed milling experiment was performed in mold steel P20 using cemented carbide ball-end mill to investigate the surface roughness. The effects of process parameters on roughness including spindle speed, feed per tooth and radial cutting depth were examined, and an analysis on the mechanism for two kinds of roughness of different tool paths was finished. The experimental results show that the longitudinal roughness improve obviously while the spindle speed and the feed per tooth increase on the high-speed conditions, and the transverse roughness increase significantly when the radial cutting depth increases. And for a smaller roughness value, the tool path should be selected along the direction in which the curvature changes evidently.
123
Authors: Gui Lin Wang, Zi Wen Zheng, Hai Kuan Yang, Yi Fan Dai
Abstract: Optical components with complex surfaces or microstructures are more and more widely used, but it is very difficult to manufacture these components by using traditional mechanical fabrication methods. Fast Tool Servo (FTS) system driven by piezoelectric ceramic (PZT) can manufacture these complex surfaces or microstructures efficiently and accurately, owing to its high response frequency, good dynamic performances and high stiffness. In this paper, the cutting characteristics are studied in the FTS machining process, and the identifying algorithm of tool interference is given. A set of high-powered FTS system is developed, which consists of PZT, fast feeding device, DSP28335 control panel and ultraprecision machine tool. The testing results indicate that the FTS system’s motion resolution is 1nm, the stroke is 90μm, and the response frequency is 220Hz while moving distance is 36μm. On the basis of above work, three kinds of typical workpieces with complex surfaces are manufactured by using FTS system. The measuring results indicate that surface accuracy can reach PV 0.14μm, the roughness is less than Ra 12nm, and the means are presented to improve the machining accuracy.
279
Authors: Ke Wei Lin, Xin Liu, Ming De Duan
Abstract: The integration of multi-view data in the acquisition of complex surface is researched by using the CMM (coordinate measuring machine) and the laser tracking scanning system. A multi-view data integration method based on the auxiliary reference plane is presented. With the precise auxiliary reference plane, the data measured by the different measuring devices and measuring views are aligned and the accuracy is analyzed. If the error is controlled in a certain range, this method can satisfy the demands of the model and assembly. The problems of low-efficient and low-accuracy in the data fusion of complex surface during the reverse engineering are solved. Meanwhile, the advantages of the different measuring devices and measuring methods are developed. This method has been applied to the reverse engineering development for a motorcycle cover model. The practical result shows that this new method is feasible and efficient.
1361
Authors: Ying Chun Liang, Ming Jun Chen, Ya Zhou Sun, W.X. Guo
Abstract: In order to machine the complex free surface, in this paper, NC interpolation of any complex surface is realized used the recursive reconstruction algorithm. The interpolating errors of this algorithm are controllable, and its applicability is relatively wide. Then, these NC codes of the complex human’s free surface are obtained with data exchange of the manufacturing module in the software UG, and machining simulation is obtained used NC codes. Finally, these NC codes are entered into the NC micro-machine tool, which is controlled by the PMAC and developed by ourselves, and the experimental research of the human’s free surface has been finished on this machine tool. The experimental results show that the NC interpolation accuracy of this recursive reconstruction algorithm is very high, and the machining simulation and machining experiments of the complex human’s surface are completely consistent. The study result shows that the complex surface molding is smooth and continuous, and the machined surface is satisfactory.
753
Authors: Qing Shun Bai, Ying Chun Liang, Kai Yang, Zhi Luo, Xiao Yan Fang
Abstract: Micro-mould is a necessary and productive component for the development of MEMS. However, the machining of micro-mould parts with complex 3D surfaces becomes the key problem for the development of micro machinery. In the paper, a new machining technique was introduced to manufacture micro-mould parts. With a reverse engineering technique, point cloud data were acquired and reconstructed into a 3D model of micro mould part in a computer. The numeral control code for micro-machining was also processed with the help of micro-machining simulation. The machining experiment on micro-parts with complex 3D surfaces was conducted on self-developed micro machine tools with micro-diameter ball-end cutter. High quality micro mould parts with complex 3D surfaces were obtained under these micro-milling experiments. The results will provide a perspective resolution on the manufacturing of micro-mould parts with complex surfaces.
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