| Aircraft antennas are typical high-performance mechanical parts requiring excellent electrical performance as well as high strength and stiffness, which are playing key roles in aircraft performances such as positioning, remote sensing and communication. Generally, these parts can be produced by covering metallic pattern on plastic substrates. As demands for high-performance antennas developed, smaller and lighter parts with higher electrical performance are required. Hence, a new kind of antenna with ultra-high performance produced by covering multi-scale pattern on a complex curved surface emerges. The parts have graphic features with large span, high geometric accuracy (?m) and high quality edge is required. Because of the above characteristics, existing processing methods can hardly meet manufacturing demands due to low precision and efficiency. Therefore, the development of processing methods greatly influences the improvement of aircraft performance, leading to great challenges in processing technologies.With the rapid development of aircrafts, the study of high-precision and efficient CNC machining methods for processing multi-scale pattern on complex curved surfaces is of great significance. In processing the metallic pattern covered on complex curved surfaces, the laser machining method and micro milling technology can be referential for the high-precision manufacturing of such parts. Therefore, base on analyzing the advantages and disadvantages of single method, an innovative processing technology combining laser etching and micro-milling is presented in this article. The combined processing technology realizes the efficient removal of large-area metal cladding due to the high efficiency of laser processing. Besides, the high-precision manufacturing of small areas and the edges of the macro graphics can be achieved with the aid of micro-milling. To solve the key technical problems which still restrict the industrial application of the new method, a series of research work are carried out in this paper. Researches include high precision laser processing technologies considering dynamic characteristics of machine tools, burr controlling methods in micro-milling, and the development of five-axis CNC machining equipment with combined process. In addition, machining experiments for high-performance antennas with complex curved surface covered by multi-scale pattern are machined. Specific contents of the research are as follows:(1) The pattern of antenna parts has characteristics of complex variable curvatures, due to the constraints of machine tool dynamic performance, the feed speed during the process of high-speed laser machining changes continuously. This may lead to uneven removals, large trajectory profile errors and poor edge quality of machining parts after processing. Considering the dynamic characteristics of machine tools, it is necessary to earry out researches for laser processing of complex pattern. In this paper, research experiments for laser processing provide the basis for the selection of an optimum combination of parameters. According to the heat balance principle, a relation model connecting the laser energy and feed speed based on the constraint of constant removal amount is established. Besides, a control algorithm for the adaptive adjustment of the output energy of laser according to the actual feed speed is studied. Moreover, combining with the subregional machining method with variable speeds, a cooperative control technology for the processing feed speed and laser power is developed considering the dynamic performance of machine tools. Through the above research, smooth edges of macro graphic are guaranteed, laying a foundation for the machining process of micro-milling for edge clearing.(2) To solve problems caused by the manufacturing difficulties by high-speed laser machining methods, micro milling is employed to realize the high-precision manufacture and edge finishing of large areas. Considering the small binding force between the metal cladding layer and the substrate, the small size of cutting tools and the good ductility of processed materials, the researches of burr control technologies are carried out. The reasonable range of processing parameters and processing strategy are obtained by experimental studies. Moreover, by setting the minimum burr size as a goal, an optimization method for multi-technological parameters is proposed based on the second order response surface method, processing parameters requirements of the edge quality can be guaranteed by the patterns combination. In addition, a cutting depth compensation method for the free surface of parts based on shape processing technique is studied. Through the above study, the high-quality manufacturing of patterns on surface of parts can be realized.(3) Based on the proposed method "laser machining of large-area+ high-precision manufacturing and edge clearing by micro milling", a multi-technology five-axis CNC machining equipment combining is developed. Through precision connection of these two kinds of processing methods, multi-scale manufacturing can be achieved through one-time clamping. Besides, the manufacturing precision of patterns on complex curved surface can be improved with the aid of the precise positioning function of the CNC machine tools, ensuring the consistency of such parts in the unit and batch.Finally, by using the proposed manufacturing method and the developed five-axis CNC machining equipment, the manufacturing of typical parts is realized. Machining results show that the high-precision manufacture of multi-scale patterns covered on the complex curved surface of engineering plastic parts can be realized by the proposed the multi-technology processing method and equipment... |
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