Alternating Inner Outer Cutting Thin-Walled Rotors

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Solution Overview

Problem

Thin-walled materials in rotating machinery, such as jet engine components, experience chattering vibrations during finish cutting due to thin wall thickness, necessitating the use of chattering vibration preventers which complicate the cutting process.

Innovation Solution

A cutting method where the inner and outer round surfaces are alternately cut with the cutting tool fed from one end to the other while rotating, utilizing the remaining stock on the opposite side to support cutting force, eliminating the need for chattering vibration preventers and preventing deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the wall thickness is reduced to create thin-walled materials, then the weight and material usage are reduced, but chattering vibration and deformation easily occur during finish cutting

Engineering Contradiction:
Improvematerial usageVSAvoidcutting stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The cutting process is segmented into multiple alternating passes between inner and outer surfaces, with each pass removing only a portion of the required material. This segmentation allows the workpiece to maintain structural integrity during each individual cutting pass while achieving the final thin-walled geometry through cumulative material removal.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method performs preliminary rough cutting to establish the basic geometry before performing finish cutting. The rough cutting creates a sufficient stock margin that provides structural support during the subsequent finish cutting operations, preventing chattering vibration while allowing the final thin-walled dimensions to be achieved.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a chattering vibration preventing retainer is used during finish cutting, then chattering vibration is suppressed, but the cutting process complexity and device requirements increase

Engineering Contradiction:
Improvecutting stabilityVSAvoidcutting process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The workpiece itself serves as the support structure during cutting by maintaining sufficient stock margin on the opposite side. The remaining material on the uncut side provides natural structural support and damping, eliminating the need for external chattering vibration preventers or retainers.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method performs partial cutting passes that remove less material than the final required depth in each individual pass. By alternating between inner and outer surfaces and leaving excess stock margin, the process achieves vibration-free cutting without requiring additional support devices, and the excess material is removed in subsequent alternating passes.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2305403B1Method of cutting a thin-walled member
Publication Date: 2019.09.04 IHI CORP
  • EP2305403B1 patent drawingFigure 1A~2
  • EP2305403B1 patent drawingFigure 3~4
  • EP2305403B1 patent drawingFigure 5

AI summary

A method which is able to, without using a chattering vibration preventing retainer, cut a thin-walled member without causing chattering vibration. A method of cutting a thin-walled material performs the following: (A) prepares a material 5 having much stock for obtaining a thin-walled material 3, (B) while rotating the material 5 about a center axis C1, cuts the inner round surface 3a of the material 5 by a desired distance within a predetermined range by feeding a cutting tool relative to the material 5 by the desired distance from the one end side to the other end side of the material along the center axis C1, (C) while rotating the material 5 about the center axis C1, cuts the outer round surface 3b of the material 5 by a desired distance within a predetermined range by feeding the cutting tool relative to the material 5 by the desired distance from the one end side to the other end side of the material along the center axis C1, and (D) alternately repeats (B) and (C) to finish the predetermined ranges of the inner round surface 3a and the outer round surface 3b.