In-Machine Workpiece Measurement with Chip-Aware Probe Path Checking

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Solution Overview

Problem

Existing measurement methods for machined workpieces inside machine tools are inaccurate due to adhering chips, which can also damage the touch probe during measurement.

Innovation Solution

A measurement method that uses a camera to capture images of the workpiece and determine if chips are present on the probe's movement path, allowing measurement only when no chips are detected, and includes a removal step to clear chips if necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a touch probe is brought into contact with the workpiece for measurement, then measurement can be performed, but chips may adhere to the workpiece causing inaccurate measurement and may damage the probe

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidprobe damage risk

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary detection of chips on the workpiece surface using a camera before the measurement process. The detection unit captures images of the workpiece and identifies chip locations in advance, allowing the system to determine whether measurement can proceed safely without probe damage risk.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A camera-based detection unit serves as an intermediary between the workpiece and the touch probe. This intermediary detects the presence and location of chips on the workpiece surface, providing information that determines whether the probe should proceed with measurement, thus preventing direct contact between the probe and chips.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If chips are removed from the workpiece before measurement, then measurement accuracy improves, but additional processing time is required

Engineering Contradiction:

Improvedimension measurement accuracyVSAvoidmeasurement process time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs partial detection rather than complete surface inspection - it specifically detects chips only in the measurement area where the probe will contact the workpiece. This selective detection approach reduces processing time compared to examining the entire workpiece surface while still ensuring measurement accuracy.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system replaces mechanical chip removal methods with optical detection. Instead of using mechanical means to remove all chips from the workpiece, the patent uses a camera-based optical detection system to identify chip locations, allowing measurement to proceed when chips are absent from the measurement area without time-consuming mechanical intervention.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240342806A1Workpiece measurement method in machine tool and machine tool

Publication Date: 2024.10.17 DMG MORI CO LTD

AI summary

A measurement method uses a measurement device including a probe to measure a workpiece machined by a machine tool. The method measures the workpiece by moving the probe into contact with the workpiece in a state where the workpiece is held by the machine tool, and the method includes an image capture step (S22) of capturing an image of a portion to be measured of the workpiece with a camera and a determination step (S23) of processing the image captured with the camera and determining whether or not a chip is present on a movement path along which the probe is to be moved. The measurement of the workpiece using the probe is executed when no chip is present on the movement path of the probe in the determination step (S23).