Vibration Cutting Control for Finish Allowance and Tool Load

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Solution Overview

Problem

Conventional machine tools face issues with uncut portions on the workpiece surface after vibration cutting, leading to excessive load on the tool during finish-cutting.

Innovation Solution

The machine tool incorporates a control device with a finishing allowance calculation means to determine the expected uncut portion and a determination means to check if it exceeds a threshold value, preventing excessive load by adjusting cutting parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vibration cutting is performed with large vibration amplitude to improve cutting efficiency, then productivity increases, but the uncut portion on the workpiece surface increases leading to excessive load on the tool during finish-cutting

Engineering Contradiction:
Improvecutting efficiencyVSAvoidsurface accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The control device calculates the uncut portion amount before finish-cutting begins, and issues warnings or adjusts vibration parameters in advance to prevent excessive tool load during finish-cutting. This preliminary calculation and prediction action allows the system to proactively manage the trade-off between productivity and precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system calculates the uncut portion amount based on vibration cutting parameters and provides feedback through warnings or automatic parameter adjustments. This feedback mechanism enables dynamic optimization of vibration amplitude and frequency to maintain both high productivity and acceptable surface accuracy.

Inventive Principle:
Principle #23Feedback

2Loss of time

If vibration cutting parameters are increased to reduce processing time, then productivity improves, but the uncut portion becomes larger requiring excessive tool load during finish-cutting

Engineering Contradiction:
Improveprocessing timeVSAvoidtool load
Core Design Contradiction:
Loss of timeVSForce

Solution Approach 1:

The control device performs preliminary calculation of the uncut portion amount based on planned vibration cutting parameters before actual finish-cutting begins. This allows the system to predict and prevent excessive tool load by adjusting parameters in advance, maintaining both short processing time and acceptable tool load levels.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts vibration cutting parameters (amplitude, frequency, feed rate) to optimize the balance between processing time and uncut portion size. By changing these parameters based on calculated uncut portion amounts, the system prevents excessive tool load while maintaining efficient processing.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the cutting program is designed to pass through previously cut portions to break chips, then chip evacuation improves, but the uncut portion amount increases due to the idle-swing period

Engineering Contradiction:
Improvechip evacuationVSAvoiduncut portion control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The control device calculates the uncut portion amount considering the chip breaking path design before cutting begins. This preliminary calculation allows optimization of the cutting program to balance chip evacuation requirements with uncut portion control, preventing excessive tool load during finish-cutting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system allows partial overlap of cutting paths to break chips, but uses preliminary calculation to ensure the uncut portion remains within acceptable limits. This partial action approach balances chip evacuation needs with precision requirements.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration enables the machine tool to prevent excessive load on the tool during finish-cutting, ensuring accurate cutting and prolonging tool life.

Implementation Method 1

a vibrating means for vibrating the workpiece held by the workpiece holding means and the tool held on the tool post relative to each other in a direction perpendicular to the axis of the workpiece under predetermined vibration conditions

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3871811B1Machine tool and control device
Publication Date: 2025.03.05 CITIZEN WATCH CO LTD
  • EP3871811B1 patent drawingFigure 1
  • EP3871811B1 patent drawingFigure 2
  • EP3871811B1 patent drawingFigure 3

AI summary

A machine tool (1) and a control device (C) therefor, wherein vibration cutting of a workpiece (W) is carried out by means of a tool (130), by relatively vibrating the workpiece (W) and the tool (130) in a direction perpendicular to an axial center of the workpiece (W) while relatively rotating the workpiece (W) and the tool (130), and relatively moving them in a feed direction and wherein, after the vibration cutting, finish-cutting is carried out for cutting a finishing allowance of the workpiece (W) by means of the tool (130), without relative vibration between the workpiece (W) and the tool (130), by relatively rotating the workpiece (W) and the tool (130) and relatively moving them in the feed direction and. According to the invention, before the vibration cutting, a finishing allowance calculation means (C2) calculates a finishing allowance remaining on the workpiece (W) after vibration cutting has been completed, and a determination means (C3) determines whether or not the finishing allowance as calculated by the finishing allowance calculation means (C2) is less than, or equal to a predetermined threshold value.