Turning Tool Eddy Current Sensing for In-Process Dimension Measurement

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Solution Overview

Problem

The existing cutting tools equipped with optical distance sensors face instability in measurement due to coolant droplets and chips adhering to the machined surface, leading to inaccurate dimension measurement.

Innovation Solution

A turning tool with an eddy current sensor attached to the tool main body, allowing for accurate measurement of machined surfaces without the need to separate from the workpiece, and capable of measuring surfaces in different directions without changing the workpiece orientation, using a configuration with a first distance sensor on the radial side and a second on the axial side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an optical distance sensor is used for measurement, then dimension measurement can be performed during machining, but measurement accuracy deteriorates due to coolant droplets and chips adhering to the machined surface

Engineering Contradiction:

Improvemeasurement efficiencyVSAvoiddimension measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the optical distance sensor with an eddy current sensor. The eddy current sensor uses electromagnetic induction to detect the distance between the sensor and the machined surface, which is not affected by coolant droplets or chips. This substitution resolves the contradiction by maintaining measurement efficiency while eliminating the sensitivity to environmental disturbances that plague optical sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement principle from optical detection to electromagnetic detection. By using an eddy current sensor that measures electrical impedance changes caused by eddy currents in the conductive workpiece, the system achieves measurement capability that is insensitive to coolant and chip interference, thus improving measurement accuracy while maintaining productivity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the turning tool is separated from the workpiece for measurement, then measurement accuracy can be improved, but measurement time increases

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The eddy current sensor enables continuous measurement during machining by eliminating the need to separate the tool from the workpiece. The electromagnetic measurement principle allows the sensor to accurately measure the machined surface even in the presence of coolant and chips, resolving the contradiction between maintaining measurement accuracy and minimizing measurement time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If an optical distance sensor is used in wet machining, then measurement can be performed, but measurement stability deteriorates due to environmental disturbances

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidmeasurement stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent substitutes the optical distance sensor with an eddy current sensor that uses electromagnetic induction. The eddy current sensor detects changes in electrical impedance caused by eddy currents induced in the conductive workpiece, a measurement principle that is inherently insensitive to coolant droplets, chips, and other environmental disturbances in wet machining. This substitution maintains measurement capability while dramatically improving measurement stability and reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 stable and accurate dimension measurement in both wet and dry machining environments, reducing measurement time and improving measurement accuracy by using eddy current sensors that are less affected by environmental disturbances.

Implementation Method 1

the distance sensor is an eddy current sensor

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Implementation Method 2

the eddy current sensor is likely to have stable measurement accuracy with respect to disturbances such as the surrounding environment

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20240173777A1Turning tool

Publication Date: 2024.05.30 MITSUBISHI MATERIALS CORP

AI summary

A turning tool includes a tool main body that extends along a tool axis and that has a pedestal at a tip portion, a cutting insert that is detachably attached to the pedestal, and a distance sensor that is attached to the tool main body. Herein, the distance sensor is an eddy current sensor. With such a turning tool, accuracy of dimension measurement can be improved.