Cutting Condition Design Method for Chatter Prevention

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Solution Overview

Problem

Existing methods for designing cutting conditions in cutting processes, such as those using end mills or milling cutters, face challenges in preventing chattering vibrations, ensuring tool life, and optimizing cutting efficiency, particularly for complex workpieces, leading to suboptimal machining accuracy and increased costs due to excessive margin settings by inexperienced operators.

Innovation Solution

A method that calculates the deflection amount of the cutting tool using feed speed, axial, and radial cutting amounts, determines the occurrence of chattering vibrations, calculates the maximum cutting thickness and cutting temperature, and optimizes cutting efficiency by adjusting the cutting speed and amounts to ensure compatible tool life and efficiency, using design parameters like feed speed, axial and radial cutting amounts, and cutting speed to determine suitable cutting conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If cutting conditions are designed with a large margin to ensure tool life, then tool life is extended, but cutting efficiency decreases and manufacturing cost increases

Engineering Contradiction:
Improvetool lifeVSAvoidcutting efficiency
Core Design Contradiction:
Duration of action of moving objectVSProductivity

Solution Approach 1:

The invention changes the parameters used to evaluate cutting conditions from traditional metrics (cutting speed, feed rate alone) to a comprehensive evaluation system that includes vibration occurrence probability, tool life, and cutting efficiency. By calculating a composite evaluation value from multiple parameters, the system identifies optimal cutting conditions that balance tool life extension with maintained cutting efficiency, avoiding excessive margin settings.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If cutting speed is reduced to prevent chattering vibration, then machining accuracy is improved, but cutting efficiency decreases

Engineering Contradiction:
Improvemachining accuracyVSAvoidcutting efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention performs preliminary evaluation of vibration occurrence probability before actual cutting by calculating it from cutting conditions, tool characteristics, and workpiece properties. This allows operators to predict and prevent chattering vibrations in advance by selecting cutting conditions with low vibration probability, thereby maintaining both high machining accuracy and cutting efficiency without needing to reduce cutting speed as a precaution.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If cutting conditions are designed by inexperienced operators with large margins, then reliability is improved, but manufacturing cost increases due to excessive conservatism

Engineering Contradiction:
Improvecutting process reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention enables the cutting condition design system to serve itself by automatically evaluating multiple criteria (vibration probability, tool life, cutting efficiency) and determining optimal conditions without relying on operator experience. The system objectively calculates evaluation values and identifies the best cutting conditions, eliminating the need for inexperienced operators to add excessive safety margins, thus reducing manufacturing costs while maintaining reliable cutting processes.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3093090B1Method for designing cutting conditions for cutting
Publication Date: 2018.07.04 KOBE STEEL LTD
  • EP3093090B1 patent drawingFigure 1
  • EP3093090B1 patent drawingFigure 2
  • EP3093090B1 patent drawingFigure 3~4

AI summary

Design parameters of a cutting tool (1), which include the feed speed (f), the cutting depth (da) in an axial direction, the cutting depth (dr) in a radial direction, and the cutting speed (v), are used to calculate the deflection amount (α) of the cutting tool (1). It is determined whether chatter vibration of the cutting tool (1) will occur, on the basis of the deflection amount (α) and a prescribed threshold value (β), and the maximum cutting thickness (Ctmax) is calculated on the basis of the determination result. The cutting temperature (t) is calculated from the maximum cutting thickness (Ctmax) and the cutting speed (v), and it is determined whether the tool life will be fulfilled, on the basis of the cutting temperature (t) and a prescribed threshold value (γ). The cutting efficiency (e) is calculated on the basis of the determination result, and the calculated cutting efficiency (e) is compared with previously stored cutting-efficiency data, and, in cases when the calculated cutting efficiency (e) is the maximum value in the data, the design parameters are set as cutting conditions.