Machine Tool Vibration Control for Chip Separation and Roundness

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Solution Overview

Problem

Conventional machine tools often fail to achieve optimal roundness and surface finish quality of workpieces due to inadequate chip separation and vibration techniques, resulting in poor visual appearance and roughness of machined surfaces.

Innovation Solution

A control apparatus for a machine tool that disperses the intersections of cutting tool paths in both the direction of relative rotation and feeding, allowing for uniform dispersion of small concave and convex portions on the workpiece surface, with adjustable vibration frequency and amplitude to optimize surface roughness and appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If vibration means is used to separate chips during cutting, then chip separation is improved, but the roundness and surface finish quality of the workpiece deteriorates

Engineering Contradiction:
Improvechip separationVSAvoidroundness and surface finish quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention applies dynamic control by making the vibration frequency variable rather than fixed. The control apparatus adjusts the vibration frequency dynamically during the cutting process, allowing the system to optimize both chip separation and surface finish quality by adapting the vibration characteristics to different machining conditions and workpiece geometries.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of vibration frequency from a constant value to a variable parameter. By modifying the vibration frequency during machining, the system can control the dispersion of cutting tool path intersections, thereby improving surface finish quality while maintaining effective chip separation through appropriate vibration.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If vibration frequency is increased to improve chip separation, then chip separation efficiency is improved, but surface roughness deteriorates unexpectedly

Engineering Contradiction:
Improvechip separation efficiencyVSAvoidsurface roughness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention implements feedback control where the control apparatus monitors machining conditions and adjusts the vibration frequency accordingly. This feedback mechanism prevents unexpected deterioration of surface roughness by adapting the vibration frequency to maintain optimal cutting conditions throughout the machining process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static vibration frequency to dynamic vibration frequency control. The vibration frequency is adjusted in real-time based on machining progress, allowing high vibration frequencies to be used when chip separation is needed while lowering frequencies when surface finish quality is the priority.

Inventive Principle:
Principle #15Dynamics

3Speed

If cutting tool path intersections are concentrated, then machining speed is improved, but concave and convex portions on the machined surface become non-uniform

Engineering Contradiction:
Improvemachining speedVSAvoiduniformity of surface features
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The invention uses parameter changes in vibration frequency to control the spatial distribution of cutting tool path intersections. By adjusting the vibration frequency, the system can disperse intersections uniformly across the machined surface while maintaining efficient machining speeds, transforming concentrated intersections into a uniform pattern.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves the roundness and visual appearance of finished workpieces by uniformly dispersing concave and convex portions, maintaining surface roughness quality and avoiding unexpected deterioration, while allowing for precise adjustment of vibration parameters to enhance machining results.

Implementation Method 1

vibration means for causing relative reciprocal vibration between the workpiece holding means and the tool rest so that the cutting tool is fed in the feeding direction while reciprocally vibrating in the feeding direction

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3275591B1Machine tool and control device for said machine tool
Publication Date: 2022.12.07 CITIZEN WATCH CO LTD
  • EP3275591B1 patent drawingFigure 1
  • EP3275591B1 patent drawingFigure 2
  • EP3275591B1 patent drawingFigure 3

AI summary

[Abstract] To provide a machine tool that, in addition to sequentially separating a chip generated from a workpiece in a reliable manner, improves the roundness of the finished workpiece and improves the visual appearance and roughness of a machined surface of the workpiece, and a control apparatus of the machine tool. A machine tool (100) or a control apparatus (C) thereof includes vibration frequency setting means (C1) for setting vibration frequency of the reciprocal vibration with respect to one relative rotation when machining a workpiece (W) so that the intersections CRs of paths of a cutting tool (130) during forward movement and backward movement are dispersed on a circumferential surface of the workpiece.