Touch Trigger Probe Compensation from 180-Degree Measurements
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Solution Overview
Problem
Existing methods for calibrating touch trigger probes to compensate for measurement errors due to temporal changes, such as thermal distortion, are burdensome and time-consuming, often requiring frequent recalibration and additional equipment setup, which can impair accuracy and increase operator workload.
Innovation Solution
A compensation value inspection system and method that calculates an initial offset displacement amount and offset-displacement-amount-during-inspection using a touch trigger probe mounted on a machine tool's main spindle, allowing for minimal frequency recalibration by estimating errors based on measurements at varying angles, reducing the need for additional calibration references and double-coordinate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration work is performed frequently to maintain measurement accuracy, then measurement precision is improved, but productivity deteriorates due to increased operational burden and time consumption
Solution Approach 1:
The system performs preliminary actions by automatically calculating compensation values and notifying operators before measurement accuracy significantly deteriorates. The notification mechanism alerts operators in advance when compensation values exceed thresholds, allowing calibration to be performed at optimal moments rather than through frequent mandatory recalibration, thus maintaining precision while reducing operational burden.
2Measurement precision
If calibration references are always installed inside the machine tool to enable frequent calibration, then measurement precision is improved, but the area for installing workpieces deteriorates and device complexity increases
Solution Approach 1:
The calibration reference (reference ball) is extracted from the machine tool interior and placed on the workpiece instead. This extraction resolves the space conflict by eliminating the need for dedicated calibration reference installation space within the machine tool, while still enabling accurate calibration measurements to be performed on the workpiece surface.
3Measurement precision
If the touch trigger probe is recalibrated frequently to compensate for thermal distortion, then measurement precision is improved, but loss of time increases due to repeated calibration operations
Solution Approach 1:
The system continuously monitors compensation values and provides feedback to operators when these values exceed predetermined thresholds. This feedback mechanism enables calibration to be performed only when necessary, rather than on a fixed frequent schedule, thereby maintaining measurement precision while minimizing the time lost to calibration operations.
Solution Approach 2:
The notification mechanism performs preliminary action by alerting operators before measurement accuracy significantly deteriorates. This allows calibration to be performed at optimal moments when compensation values first exceed thresholds, rather than through frequent mandatory recalibration, thus reducing overall calibration time while maintaining precision.
4Measurement precision
If double coordinate measurement is performed to cancel measurement errors, then measurement precision is improved, but productivity deteriorates due to increased measurement time
Solution Approach 1:
The invention extracts and separately measures the compensation value as a distinct parameter from the actual workpiece measurements. By dedicating a specific measurement angle (e.g., 0 degrees) solely for compensation value acquisition and separating this from workpiece measurement angles, the system obtains necessary calibration data without requiring double measurement of workpiece coordinates, thus maintaining precision while improving efficiency.
Data Source
AI summary
A compensation value of a touch trigger probe inspection system includes an initial offset value estimating unit, an offset value-during-inspection estimating unit, and a compensation value error estimating unit. The offset value-during-inspection estimating unit calculates a value of an offset-displacement-amount-during-inspection based on an inspection-measurement-result-before-inversion and an inspection-measurement-result-after-inversion. The inspection-measurement-result-before-inversion is obtained by measuring a measurement object during inspection at the first reference measurement angle. The inspection-measurement-result-after-inversion is obtained by measuring the measurement object during inspection at the measurement angle varied by 180° from the first reference measurement angle. The compensation value error estimating unit estimates an error of a compensation value of the touch trigger probe based on the initial value of the offset displacement amount and the value of the offset-displacement-amount-during-inspection.