A milling cutter for processing steam turbine blade fir tree-shaped blade root and its design method

Abstract

The invention provides a milling cutter for machining fir-tree roots of steam turbine blades and a design method of the milling cutter. The milling cutter is capable of solving various problems, such as short service life of cutter and tooth tools, great damage to a machine tool, low cutting efficiency, declining of surface quality of workpieces after rough milling and so on, during rough milling of fir-tree roots of steam turbine blades by using an existing integrally-formed milling cutter. The milling cutter comprises a front milling cutter tenon teeth and a rear milling cutter with tenon teeth; front tenon teeth are formed at a periphery of the front milling cutter with tenon teeth, while rear tenon teeth are formed at a periphery of the rear milling cutter with tenon teeth; tooth shapes of the front tenon teeth and tooth shapes of rear tenon teeth are theoretical front tenon tooth shapes and theoretical rear tenon tooth shapes, both of which are formed, according to theoretical tooth shapes of the fir-tree roots of the steam turbine blades, by determining split boundaries at crests of second teeth and carrying out extension and splitting in an axial direction and a tangential direction from the split boundaries, respectively.

Description

technical field [0001] The invention relates to the field of processing tooling for steam turbine blades, in particular to the field of tooling for rough milling processing of fir-tree-shaped blade roots of large-scale steam turbine blades, in particular to a milling cutter design method and design for machining fir-tree-shaped blade roots of steam turbine blades method. Background technique [0002] Usually, the fir tree-shaped blade root tooth profile of large steam turbine blades (see figure 1 ) Rough milling mostly uses integral form milling cutters (see figure 2 ) for simultaneous cutting of the overall tooth profile. Since the theoretical profile of the entire fir tree-shaped leaf root tooth profile expands to a length of 180 mm, the cutting resistance is very large during overall milling, and the instantaneous cutting power of the machine tool can reach 70%, which is It causes a lot of cutting vibration, which brings great damage to the main shaft and screw of the ...

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Problems solved by technology

[0003] In view of the above problems, the present invention provides a milling cutter for processing the fir tree-shaped blade root of a steam turbine blade, which can solve the problem of rough milling of the fir tree-shaped blade root tooth profile of a large steam turbine blade by using an integral form milling cutter. There are many problems such as short service life of cutting tools, large damage to machine tools, low cutting efficiency, and decline in surface quality after rough milling of workpieces.

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