Machine Tool Vibration Control for Stripe-Free Surface Cutting

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Solution Overview

Problem

Conventional machine tools are limited in their ability to adjust vibration frequency and number of rotations, leading to suboptimal cutting performance and surface quality, resulting in stripe patterns on the machining surface.

Innovation Solution

A control apparatus that allows for adjustable settings of the number of rotations and vibrations based on vibration frequency, enabling precise control of the cutting process to improve surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the control apparatus issues operation instructions at a predetermined cycle, then the control system operates with simple timing, but the vibration frequency is limited and cannot achieve optimal cutting performance

Engineering Contradiction:
Improvecutting performanceVSAvoidcontrol timing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control apparatus dynamically adjusts the operation instruction cycle based on the vibration frequency of the cutting tool. Instead of using a fixed predetermined cycle, the control timing is made adaptive to match the actual vibration characteristics, enabling optimal cutting performance while maintaining manageable control complexity through automated synchronization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the timing parameter (operation instruction cycle) according to the vibration frequency parameter. By linking the control cycle to the actual vibration frequency, the system optimizes cutting performance without requiring complex independent control mechanisms, as the parameter adjustment is directly tied to measurable physical characteristics.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the cutting tool reciprocates at fixed vibration frequency, then the control is simple, but stripe patterns are generated on the machining surface

Engineering Contradiction:
Improvesurface qualityVSAvoidcontrol simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The vibration frequency is made dynamic rather than fixed. The control apparatus adjusts the operation timing to synchronize with the actual vibration frequency, which can vary during machining. This dynamic adaptation eliminates stripe patterns by ensuring proper chip separation while keeping the control system relatively simple through automated frequency tracking.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback from the actual vibration frequency to adjust the operation instruction timing. By monitoring the vibration characteristics and adapting the control cycle accordingly, the system maintains high surface quality without requiring complex manual intervention, as the feedback loop automatically compensates for frequency variations.

Inventive Principle:
Principle #23Feedback

3Reliability

If the number of vibrations per rotation is not matched to rotation speed, then the control is straightforward, but chip separation is insufficient and cutting is not smooth

Engineering Contradiction:
Improvechip separation qualityVSAvoidcoordination control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically coordinates the number of vibrations with the rotation speed by adjusting the operation instruction cycle. Instead of using fixed ratios, the control apparatus adapts the timing to match the actual vibration frequency and rotation characteristics, ensuring proper chip separation while maintaining manageable control complexity through automated synchronization.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3354403B1Machine tool control device, and machine tool equipped with said control device
Publication Date: 2025.01.08 CITIZEN WATCH CO LTD
  • EP3354403B1 patent drawingFigure 1
  • EP3354403B1 patent drawingFigure 2
  • EP3354403B1 patent drawingFigure 3

AI summary

To provide a machine tool and a control apparatus of the machine tool that, in accordance with user set conditions, feeds a cutting tool in a feeding direction while reciprocatively vibrating the cutting tool and smoothly cuts a workpiece and that can improve the appearance of a machining surface of the workpiece. In a machine tool (100) and a control apparatus (C) thereof, control means (C1) is configured to set the number of rotations of relative rotation and the number of vibrations of reciprocating vibration during one rotation of the relative rotation in accordance with a vibration frequency attributable to a cycle during which an operation instruction can be issued, and the control means (C1) includes adjusting means configured to adjust the number of rotations or the number of vibrations, which is set by the control means.