Multi-axis linkage numerical control machining method of large hydraulic turbine blade based on casting blank

Abstract

The invention discloses a large-sized water turbine blade multi-shaft linkage numerical control machining method based on a casting roughcast. The method comprises the steps: 1) carrying out a three-dimensional coordinate measurement on a water turbine blade roughcast by a large-sized coordinate measuring machine, carrying out a point cloud acquisition of the blade roughcast by a scanner; 2) according to three-dimensional coordinate data and point cloud data of the blade roughcast obtained in the step 1), processing the three-dimensional coordinate data and the point cloud data of the blade roughcast by a computer, and then generating a computer model of the blade roughcast entity; and 3) based on the computer model of the blade roughcast entity obtained in the step 2), machining the roughcast entity of the giant water turbine blade by a numerical control programming, planning tool paths, and performing a machine simulation cutting emulation. Through the method, the accurate computer model of the blade roughcast entity can be obtained, and the roughcast entity can be flexibly preprocessed; the tool path empty knives are fewer, and thus the machining efficiency is high; the cutter spacing is reliable, and thus the quality accident is reduced; and the cutting condition is good, and thus the effective utilization rate is high.

Description

technical field [0001] The invention relates to a numerical control machining method for a blade of a large water turbine, in particular to a multi-axis linkage numerical control machining method for a blade of a large water turbine based on a casting blank. Background technique [0002] The water turbine is the prime mover of hydroelectric power generation, and the quality of the runner blades of the water turbine has a huge impact on the safety, reliability and economical operation of the hydropower unit. The turbine runner blade is a very complex sculpture surface. In the manufacturing process of large and medium-sized units, the manufacturing process of "sand casting-grinding wheel shovel grinding-three-dimensional sample inspection" has been adopted for a long time, which cannot effectively guarantee the accuracy and manufacturing quality of the blade surface. The current multi-axis linkage CNC machining technology is a cutting-edge high-tech in today's mechanical proc...

AI Technical Summary

Problems solved by technology

The main disadvantages of this method are: the status of the blank in the area with large curvature and the convex-concave area of ​​the blade surface cannot be accurately grasped; the physical condition of the blank is greatly affected by human factors and technical conditions, and there is no way to obtain the blank entity

In the multi-axis linkage machining of giant blades, the generated tool positions can only be generated using the theoretical model as a reference. The operability of the tool positions is poor, and there are many empty tool positions, which affects the processing efficiency

[0005] 3) In the prior art, machine tool operators carry out sub-area processing according to the numerical control technical documents. Since the blade margin is extremely uneven, the machining of some areas with large margins needs to be processed multiple times, that is, the measurement data of the blank is processed. Allowance estimation, to determine the amount of tool lift in the entire processing area, resulting in multiple empty tool passes in local areas; during rough machining, some cutting process parameters can only be set according to theoretical values, and the actual cutting conditions are greatly affected by the status of the blank Large, resulting in low service life of the blade and low effective utilization of the machine tool