Turning Tool Position Correction for 10 µm Finishing Accuracy

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Solution Overview

Problem

Existing turning methods struggle to achieve narrow dimensional tolerances without relying on grinding, as thermal displacement and tool wear lead to inaccuracies and increased machining time.

Innovation Solution

A turning method and system that utilize multiple movement apparatuses to precisely adjust and correct the position of a turning tool in both radial and axial directions, allowing for accurate finishing without grinding, by measuring and recalculating the cutting edge position to achieve high positional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If turning is performed with a grinding allowance left beforehand to achieve narrow dimensional tolerance, then manufacturing precision is improved, but productivity deteriorates due to the need for additional grinding operations

Engineering Contradiction:
Improvedimensional toleranceVSAvoidmachining time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the actual dimension of the workpiece is measured after turning, the deviation from the target dimension is calculated, and the tool position is automatically corrected based on this feedback. This closed-loop control enables achieving narrow dimensional tolerances (10 μm or less) through turning alone, eliminating the need for subsequent grinding operations and thereby improving productivity while maintaining high precision

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the tool position parameters (radial and axial coordinates) based on measured dimensional deviations. By changing the tool position parameters in real-time according to actual workpiece dimensions, the system achieves high manufacturing precision without requiring additional grinding passes, thus resolving the contradiction between precision and productivity

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the distance from tool post to rotation axis is finely adjusted to correct worn amount, then manufacturing precision is improved, but reliability deteriorates due to thermal displacement affecting positional accuracy

Engineering Contradiction:
Improvedimensional accuracyVSAvoidpositional stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent employs continuous feedback through measurement of the workpiece dimension and calculation of deviation from target values. This feedback loop compensates for thermal displacement effects by dynamically adjusting tool position based on actual measurements rather than relying on pre-set adjustments, thereby maintaining both precision and reliability despite temperature changes during machining

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs measurement and correction calculations before the next machining operation begins. By preparing the corrected tool position in advance based on previous measurement results, the system accounts for thermal displacement that occurred during the previous operation, ensuring reliable and accurate positioning for the subsequent machining pass

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If multiple movement apparatuses are used to precisely adjust turning tool position, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvepositional accuracyVSAvoidnumber of movement apparatuses
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the tool positioning function into two independent movement apparatuses: one for radial direction adjustment and another for axial direction adjustment. Each apparatus handles a specific dimension, simplifying the control logic for each individual device while achieving high overall positioning accuracy through their coordinated operation based on measured deviations

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4219048B1Turning method, machining system, and machining program
Publication Date: 2024.10.16 YAMAZAKI MAZAK KK
  • EP4219048B1 patent drawingFigure 1
  • EP4219048B1 patent drawingFigure 2
  • EP4219048B1 patent drawingFigure 3A~3D

AI summary

The present invention relates to a turning method for performing turning on a workpiece that rotates about a rotation axis. The turning method includes: driving a first movement apparatus for moving a turning tool in a radial direction of the rotation axis to locate a cutting edge of the turning tool at a first radial position in the radial direction; driving a second movement apparatus for moving the turning tool in parallel with the rotation axis, performing turning on the workpiece, and then moving the turning tool in a reverse direction to retract the turning tool from the workpiece; measuring a processed dimension of the workpiece, and calculating an error between the processed dimension that has been measured and a target dimension; driving a third movement apparatus for moving the turning tool relative to the first movement apparatus in the radial direction of the rotation axis to locate the cutting edge of the turning tool at a second radial position so as to correct the error; and driving the second movement apparatus to move the turning tool in parallel with the rotation axis, and performing turning on the workpiece.