Lathe Spindle Vibration Control for Polygonal Turning

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Solution Overview

Problem

Existing lathe turning technologies are limited in machining shapes other than cylindrical or columnar forms, specifically failing to efficiently create flat surfaces on the outer or inner circumferential surfaces of a workpiece.

Innovation Solution

A machine tool and control device that incorporates a rotation mechanism, movement mechanism, and vibration mechanism, controlled by a unit to synchronize tool and workpiece movements, allowing for the machining of substantially regular polygonal shapes on the outer and inner circumferential surfaces through relative vibration and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional lathe turning is used to machine cylindrical or columnar shapes, then the machining process is simple and efficient, but it is not possible to machine flat surfaces or regular polygonal shapes on the outer or inner circumferential surfaces

Engineering Contradiction:
Improvemachining capability for flat surfaces and polygonal shapesVSAvoidcomplexity of rotation and vibration control system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the cutting system dynamic through superimposing vibration on the tool holder while maintaining rotation. The tool holder is equipped with a vibration mechanism that causes it to vibrate in a direction perpendicular to the rotation axis, transforming the static lathe turning process into a dynamic one that can create polygonal and flat surfaces through controlled vibration patterns during rotation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent directly applies mechanical vibration by introducing a vibration mechanism to the tool holder that vibrates in a direction perpendicular to the rotation axis. This mechanical vibration, when synchronized with the rotation, enables the cutting tool to machine regular polygonal shapes and flat surfaces on the workpiece without requiring complex multi-axis movement mechanisms.

Inventive Principle:
Principle #18Mechanical vibration

2Adaptability or versatility

If vibration mechanism is added to machine polygonal shapes, then machining versatility is improved, but the device complexity and control difficulty increase

Engineering Contradiction:
Improveability to machine regular polygonal shapesVSAvoidcomplexity of synchronization control between rotation and vibration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies periodic action by synchronizing the periodic vibration of the tool holder with the periodic rotation of the workpiece. The control mechanism ensures that the vibration frequency and phase are coordinated with the rotation speed, creating a periodic cutting pattern that forms regular polygonal shapes. This periodic coordination simplifies the control logic compared to arbitrary multi-axis movement.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements feedback control by using a sensor to detect the rotation phase of the workpiece and adjusting the vibration phase and frequency accordingly. This feedback mechanism ensures precise synchronization between rotation and vibration, maintaining the accuracy of polygonal shape formation while simplifying the overall control through automatic phase adjustment based on detected rotation position.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If conventional lathe turning is used, then the machining process is straightforward, but excessive machining allowance is required to achieve flat surfaces or polygonal shapes

Engineering Contradiction:
Improveprecision of flat surface and polygonal shape machiningVSAvoidmachining allowance removal
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies mechanical vibration to enable precise polygonal and flat surface machining with minimal material removal. The vibration causes the tool to follow a controlled periodic path relative to the rotating workpiece, allowing the cutting edge to accurately form the desired geometry directly on the surface with only the necessary machining allowance, rather than requiring excessive material removal followed by secondary operations.

Inventive Principle:
Principle #18Mechanical vibration

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

Enables efficient machining of regular polygonal shapes on workpieces by lathe turning, achieving stable and continuous cutting without the need for excessive machining allowances.

Implementation Method 1

a vibration mechanism that vibrates the main spindle and the tool holder relative to each other in a vibration direction perpendicular to the rotation axis direction

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP4650085A1Machine tool and control device
Publication Date: 2025.11.19 CITIZEN WATCH CO LTD
  • EP4650085A1 patent drawingFigure 1
  • EP4650085A1 patent drawingFigure 2A~2B
  • EP4650085A1 patent drawingFigure 3A~3C

AI summary

A machine tool comprising a main spindle to which a workpiece 21 is to be attached; a rotation mechanism that rotates the main spindle; a tool holder that holds a tool for cutting the workpiece 21; a movement mechanism that moves the main spindle and the tool holder relative to each other in a rotation axis direction of the main spindle; a vibration mechanism that vibrates the main spindle and the tool holder relative to each other in a vibration direction perpendicular to the rotation axis direction; and a control unit that controls the rotation mechanism and the vibration mechanism. The machine tool cutting the workpiece 21 by using the movement mechanism and the vibration mechanism so as to vibrate and move the workpiece 21 and the tool relatively each other, while the rotation mechanism rotates the main spindle. The control unit driving the rotation mechanism and the vibration mechanism such that the tool is located at the same position in the vibration direction for each fixed rotation period of the main spindle and controlling the rotation mechanism and the vibration mechanism such that an outer circumferential surface or inner circumferential surface of the workpiece 21 is machined into a substantially regular polygonal shape when viewed in the rotation axis direction.