针对机匣零件粗加工过程中凸台多、加工余量大、材料难切削、刀具磨损快、加工周期长等特点，提出了一种机匣摆线粗加工刀具轨迹规划方法，该方法能有效控制切削过程中刀具负载的变化，改善刀具切削过程中的加热-冷却循环，减缓刀具的磨损，提高机匣粗加工效率。首先，通过对两种摆线模型的分析，建立了摆线铣数学模型，并分析了摆线铣的优缺点；其次，结合机匣零件特点，将模型在精度范围内离散为点模型，利用圆锥将模型展开并建立展开模型与原始模型间的映射关系。通过对可加工区域的划分和平面逼近，生成了适用于机匣零件的摆线粗加工刀具轨迹。最后，分别通过摆线铣刀具磨损实验、平面型腔摆线铣实验和机匣摆线铣实验，验证了摆线铣在降低刀具磨损、延长刀具寿命方面的有效性，以及本文轨迹生成算法在航空发动机机匣实际加工中的正确性和高效性。研究成果能有效缩短加工周期、降低加工成本，提升机匣零件的粗加工效率。
To overcome the problems in rough machining of casing parts such as multiple bosses, large machining allowance, low machinability of materials, fast tool wear and long process cycle, a tool-path planning method for the trochoidal milling of the aeroengine casing is proposed, with which the change of the tool load can be controlled effectively, the heating-cooling cycle is improved, the tool wear is retarded, and the machining efficiency can be increased in the rough machining process of casing. First of all, through an analysis of two trochoidal models, a mathematical model for the trochoidal milling is developed, and the advantages as well as the disadvantages of the trochoidal milling are discussed. Then, based on the characteristics of the casing parts, the model is discretized into a point model in the accuracy range. The model is unfolded by using the cone, and the mapping relationship between the unfolded model and the original one is established. According to the division and plane approximation of the machining area, the tool path of trochoidal rough machining for casing parts is generated. Finally, experiments on the trochoidal milling of tool wear, planar cavity and casing show that the trochoidal milling is effective in reducing the tool wear and prolonging the tool life. The validity and high efficiency of the proposed trajectory generation algorithm in the actual processing of the aeroengine casing are verified. The research achievements can effectively shorten the processing cycle, reduce the machining costs and improve the rough machining efficiency of casing parts.
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