Searching method for the maximum free motion stroke trajectory of the closed integral blisk EDM electrode

Abstract

A method for searching a maximum free movement stroke track of an electrode in electrosparking of a closed blisk is characterized in that an electrode feeding stopping position is treated as an optimal track starting point, a position where the whole electrode moves out of a flow channel is treated as an optimal track end point, a vector direction that the center of the end surface of a head part of the electrode points to the center of the end surface of a tail part of the electrode is treated as a reference direction of the electrode movement, and on that basis, the process that the electrode moves from the optimal track starting point to the optimal track end point is divided into a plurality of stages; the electrode translates from one movement node of each stage along the reference direction without interference to obtain the next movement node of the same stage, and meanwhile, the posture of a rotating shaft of the electrode is adjusted in each movement node; all movement nodes can be obtained after the electrode moves out of the flow channel without interference, and all nodes can be smoothly connected to form a complete optimal track; the optimal track is subjected to coordinate transformation to obtain an interference-free feeding track. The method is applicable to flow channel structures of various shapes, is high in success rate of searching the optimal track, can achieve multi-shaft linking, and is high in processing efficiency.

Description

technical field [0001] The invention relates to a technology in the field of mechanical automation, in particular to a method for obtaining an electrode-free feeding trajectory during the electric discharge machining process of a closed integral blisk. Background technique [0002] Blisk parts are one of the core components of aerospace engines and one of the key factors determining engine performance. With the rapid development of the aerospace industry, the demand for blisk parts is also increasing, and the requirements for its manufacturing accuracy and efficiency are also increasing. The structure of blisk parts is complex, especially the closed overall structure. There is a crown at the end of the blade, and the flow channel will present a semi-closed structure, which brings great challenges to processing. However, the blades, disk body and blade crown of the closed integral blisk are processed from the same blank, which is very difficult to process. [0003] At prese...

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Problems solved by technology

The core issue of this processing technology is how to obtain the feed trajectory without interference of the forming electrode. The acquisition of the feed trajectory is related to whether EDM can be carried out, and to a certain extent affects the efficiency of processing

[0004] After searching the existing technology, Liao Pingqiang et al. proposed a trajectory search method with the minimum reduction of the electrode as the objective function in "Research on the Search Method for the Formed Electrode Feed Trajectory in the Machining of the Crowned Integral Turbine Disk". This method requires the electrode to move stepwise along the X axis each time, and then adjust on other axes, but this method can only be searched for four-axis linkage machine tools, that is, including XYZ translation and rotation around the Z axis, for For five-axis and six-axis machine tools, this method cannot effectively utilize all degrees of freedom, and the processing capability of the machine tool cannot be fully reflected. Moreover, this method considers a single form of electrode processing, and the process of subdivision processing for electrodes is not very fast. well described

[0005] Liu Xiao and others proposed a "conjugate method" trajectory search method. By controlling the electrode to move along the centerline of the flow channel as much as possible, so that the electrode can move out of the flow channel, this method is divided into pre-optimization and In two more steps of optimization, it is necessary to adjust the tangent between the centerline of the electrode and the centerline of the flow channel at the exit position. This method can obtain the movement form of multi-axis linkage. For various forms of blisk parts, this method can easily obtain the electrode However, when the electrode is subdivided and there is a large deviation between the centerline of the electrode and the centerline of the flow channel, the search process cannot effectively use the existing movement space of the electrode, and the probability of successful search will be greatly affected

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