Vibration-reduction milling method for larger-torsion-to-rounded-angle blade profile of integral impeller

Abstract

The invention discloses a vibration-reduction milling method for a larger-torsion-to-rounded-angle blade profile of an integral impeller. According to the method, the changing range of the top rake ofa cutting tool serves as a milling smoothness evaluation index, and a rough milling area is divided into a three-dimensional cavity reciprocating layer milling area, a three-dimensional acute-angledcavity unidirectional layer milling area and a three-dimensional acute-angled cavity butt plunge milling area in the blade spreading direction in sequence; in a variable blade root rounded-angle area,the cutting removal rate uniformity serves as a milling smoothness evaluation index, according to a multi-variation blade root rounded-angle model, layered progressive processing is conducted, and through a cutting force optimization method and a rough and fine combined processing method, the integral impeller has a high processing precision and a good surface quality finally. The method aims toreduce the cutter shaft variation amplitude of the three-dimensional acute-angled cavity area of the blade and the cutter shaft variation amplitude of the variable blade root rounded-angle area, the material cutting removal rate is balanced, the blade profile cutting vibration is reduced, the smoothness of the blade profile milling process is improved, the larger-torsion-to-rounded-angle blade profile of the integral impeller is high in processing precision and good in surface quality.

Description

technical field [0001] The invention relates to the technical field of machining an integral impeller of an aero-engine, in particular to a vibration-damping milling method for a large torsion and fillet blade shape of an integral impeller. Background technique [0002] The integral impeller structure is widely used in the design of international aero-engines. It adopts a complex blade configuration with curved-sweep combination features to increase the compression ratio and improve aerodynamic efficiency. The blade shape has long overhang, large torsion, narrow spacing, and high curvature. Change characteristics, in the three-dimensional acute-angle cavity area formed by the blade body and the flow channel, the stability of the machining process is poor, the swing range of the cutter shaft is large, and the cutting force changes sharply, resulting in chatter marks, overcut, and poor shape of the front and rear edges in the local area of ​​the blade. question. The existing ...

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Problems solved by technology

[0002] The integral impeller structure is widely used in the design of international aero-engines. It adopts a complex blade configuration with curved-sweep combination features to increase the compression ratio and improve aerodynamic efficiency. The blade shape has long overhang, large torsion, narrow spacing, and high curvature. Change characteristics, in the three-dimensional acute angle cavity area formed by the blade body and the flow channel, the stability of the machining process is poor, the swing range of the cutter shaft is large, and the cutting force changes drastically, resulting in vibration marks, overcut, and poor shape of the front and rear edges in the local area of ​​the blade. question

The existing processing methods generally use reciprocating layer milling, a combination of layer milling and semi-finishing milling to process the three-dimensional acute-angle cavity area, and reduce the impact of cutting vibration by encrypting the tool track and reducing the feed speed. The efficiency of rough milling is low. The tool wears quickly and the surface quality is difficult to guarantee

In order to meet the strength and aerodynamic requirements, the transition parts of some integral impeller blades and flow channels are gradually replaced by variable blade root fillets instead of commonly used constant blade root fillets, so that the change of the cutter axis vector is further increased, and the blade root fillets are cut and removed The amount is not uniform, and the transfer area is prone to vibration marks and knife joints, and there are few discussions on the construction method and processing strategy of the variable blade root fillet at home and abroad.

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