Grinding Apparatus with Variable Infeed for Arc Profile Accuracy

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Solution Overview

Problem

Conventional machining methods for non-circular surfaces, such as crankpins, face challenges in maintaining accurate grinding and extending tool life due to sudden changes in grinding load and the need for frequent tool re-dressing, especially when cutting tools with large widths are used.

Innovation Solution

A machining apparatus with a numerical controller that controls a C-X profile motion to gradually increase the infeed amount of the cutting tool along the X-axis, tracing an arc profile and managing the grinding load, allowing for improved accuracy and extended tool life by stabilizing the machining load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a cutting tool with large width is used to machine non-circular surfaces, then machining efficiency is improved, but grinding accuracy deteriorates due to sudden changes in grinding load

Engineering Contradiction:
Improvemachining efficiencyVSAvoidgrinding accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the infeed amount variable rather than constant. The infeed amount is dynamically adjusted based on the rotational angular position of the workpiece, increasing when the cutting tool approaches the workpiece and decreasing when it moves away. This dynamic adjustment compensates for changes in grinding load, maintaining both high efficiency with wide tools and accurate grinding results.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of infeed amount according to the rotational angular position. By modifying the infeed parameter dynamically during the machining process, the system maintains stable grinding conditions despite using wide cutting tools, thereby preserving both productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a cutting tool with large width is used, then material removal rate is improved, but tool life deteriorates due to frequent re-dressing

Engineering Contradiction:
Improvematerial removal rateVSAvoidtool life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The dynamic adjustment of infeed amount based on rotational angular position prevents excessive grinding load that would cause rapid tool wear. By reducing infeed when the tool moves away from the workpiece and increasing it when approaching, the system extends tool life while maintaining high material removal rates with wide tools.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent modifies the infeed parameter dynamically to optimize tool life. This parameter change ensures that the cutting tool operates under controlled load conditions throughout the machining cycle, reducing the frequency of re-dressing and extending tool life while maintaining high productivity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If infeed amount is increased to improve machining efficiency, then productivity is improved, but machining accuracy deteriorates due to load variations

Engineering Contradiction:
Improvemachining efficiencyVSAvoidmachining accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements dynamic control of the infeed amount based on rotational angular position. This dynamic approach allows the system to use larger average infeed amounts for high productivity while compensating for load variations through angular-position-dependent adjustment, thereby maintaining machining accuracy despite increased overall infeed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The infeed parameter is changed dynamically according to rotational angular position, enabling the system to achieve high productivity through increased overall infeed while maintaining accuracy through position-specific parameter adjustment. This resolves the contradiction between productivity and precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1927911B1Machining apparatus
Publication Date: 2011.07.06 JTEKT CORP
  • EP1927911B1 patent drawingFigure 1~2
  • EP1927911B1 patent drawingFigure 3~4
  • EP1927911B1 patent drawingFigure 5

AI summary

A machining apparatus, in which a plurality of user set programs ixx relation to one axis is written and the amount of the infeed motion of the grinding wheel is increased to restrain the change of the load of the grinding wheel, improves a machining accuracy and achieve a longer life of the grinding wheel, When the grinding wheel 30 cut arc portions 11A, 11C, U having its diameter of which is gradually sxnall according to a position apart from the shoulder, the numerical controller 40 controls a rotation of the workpiece 10 around said C-axis, a motion of a grinding wheel 30 relative to the workpiece 10 along an X-axis and Z-axis to trace an arc profile of the arc portion 11A, 11C, U of the extending portion, and an infeed motion of the grinding wheel 30 to the workpiece 10 along the X-axis to increase gradually an amount of the infeed motion of the grinding wheel 30 to the workpiece I along the X-axis in order to griutd the extending portion to the arc profile and in order to increase gradually a grinding load of the grinding wheel 30.