Wheel groove broach layered multi-tool tooth groove rough/finish-milling method

Abstract

The invention discloses a wheel groove broach layered multi-tool tooth groove rough / finish-milling method. The method comprises a wheel groove broach rough-milling tooth groove machining step and a finish-milling tooth groove machining step, wherein the rough-milling tooth groove machining step comprises four steps of rough-milling machining programs; the first step of rough-milling machining program adopts three-tool machining and sequentially performs rough-milling on the middle, the toothed back and the toothed rake angle of the wheel groove broach; the second step of rough-milling machining program adopts two-tool machining and sequentially performs rough-milling on the toothed back and the toothed rake angle of the broach; the third step of rough-milling machining program adopts two-tool machining and sequentially performs rough-milling on the toothed back and the toothed rake angle of the broach; the fourth step of rough-milling machining program adopts one-tool machining and sequentially performs rough-milling on the middle of the broach; and the finish-milling tooth groove machining step performs finish-milling on the tooth groove twice, namely sequentially performing finish-milling on the toothed back of the tooth groove and performing finish-milling on the toothed rake angle of the tooth groove. The method has the advantages of high precision, high efficiency, low cost and the like and is particularly suitable for a large-pitch large-groove depth wheel groove broach.

Description

technical field [0001] The invention relates to the technical field of tooth milling, in particular to a layered multi-knife rough and fine milling gear used for milling tooth grooves of large tooth pitch, large groove and deep wheel groove broaches for processing steam turbine rotor disc wheel grooves slot method. Background technique [0002] The steam turbine is a high-precision electromechanical product integrating high temperature, high pressure and high speed. The rotor is the core part of the steam turbine, and the multi-stage disc is the main component of the rotor. In the steam turbine manufacturing industry, the processing of the steam turbine wheel groove is a very important and complicated process. The processing quality of the wheel wheel groove will directly affect the output and vibration of the steam turbine. At present, several major domestic steam turbine factories have introduced large complex and high-precision wheel groove broaching machines through tec...

AI Technical Summary

Problems solved by technology

The rotor grooves of 300MW, 600MW, and 1000MW large-scale steam turbine units are all palm tree-shaped blade root grooves, with a large profile, which requires a large profile of the broach, that is, the tooth pitch of the wheel groove broach is large, and the processing depth of the tooth groove is deep , the cutting volume is large, the cutting load is large, and the tool wears quickly during tooth groove machining, and the material of the steam turbine wheel groove broach is high-performance high-speed steel, which has high strength, poor cutting performance, and low processing efficiency

The following technical difficulties still exist in the milling of the existing wheel groove broaches with large tooth pitch and large groove deep grooves: the shape of the wheel groove broaches is various, and the tooth grooves of the wheel groove broaches need to be diversified; The contact area with the processed wheel groove broach surface is relatively large (such as figure 1 As shown), a large friction force is generated, which leads to a large cutting force and high cutting heat, a large cutting load, a large vibration of the broach, and accelerated wear of the tooth groove milling cutter

At the same time, the roughness of the tooth groove to be processed is poor, and the tooth groove of the broach is prone to stress due to extrusion. During heat treatment, the stress expands and concentrates, which easily causes thermal cracks, and even the broach loses teeth.

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