Probe Straightness Measurement Using Reference Jig
Solution Overview
Problem
Traditional methods for measuring probe straightness in surface texture measuring instruments require separate sensors, leading to economic burdens, accuracy issues, and measurement inaccuracies due to external forces from cable bending, especially when using probes with wide measurement ranges.
Innovation Solution
A method that measures probe straightness in an actual use environment without a separate sensor by using a surface texture measuring machine with a measurement jig having a known profile error, calculating straightness errors based on measured and nominal positions, and correcting for slant angles, thereby eliminating the need for external sensors and reducing external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate electro-capacitance sensor is attached to measure straightness, then measurement capability is provided, but economic burden increases and measurement accuracy is influenced by sensor accuracy and external forces
Solution Approach 1:
The probe's own displacement detector serves the dual purpose of both surface texture measurement and straightness measurement. The measurement piece itself performs the measurement function without requiring external sensors, eliminating cable bending forces and reducing device complexity while maintaining measurement capability.
Solution Approach 2:
The displacement detector originally designed for surface texture measurement is made multi-functional by utilizing it for both measurement purposes. The same detector measures both the surface texture data and the straightness of the probe, eliminating the need for separate dedicated straightness measurement sensors.
2Productivity
If probe measurement range is widened for high-speed low-measuring-force measurement, then measurement speed and measuring force are improved, but straightness of linear guide mechanism greatly influences measurement accuracy
Solution Approach 1:
The straightness measurement results obtained through this method provide feedback for correcting measurement errors. By continuously monitoring the actual position of the measurement piece against its nominal position, the system can compensate for straightness deviations and maintain high measurement accuracy even with widened measurement range.
Solution Approach 2:
The patent replaces complex mechanical straightness measurement systems with an electronic/software-based correction approach. Instead of relying solely on mechanical precision, the system uses displacement detector data and computational methods to compensate for mechanical deviations, enabling high-speed measurement without sacrificing accuracy.
3Measurement precision
If traditional straightness measurement is performed with electro-capacitance sensor, then straightness data is obtained, but attachment/detachment work and economic burden increase
Solution Approach 1:
The probe performs its own straightness measurement using its built-in displacement detector, eliminating the need for external sensors that require attachment and detachment. The measurement piece serves itself by utilizing its own measurement capabilities to assess its straightness.
Solution Approach 2:
The patent merges the straightness measurement function with the existing surface texture measurement system. By combining both measurement capabilities into a single integrated system using the same displacement detector, the need for separate attachment and detachment of dedicated straightness sensors is eliminated.
Data Source
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AI summary
A probe straightness measuring method includes: placing a measurement jig (71) having a measurement reference surface (72) with a known profile error on a stage surface (2A) of an XY stage (2) so that the measurement reference surface (72) is slanted in a moving direction of the XY stage (2); measuring a displaced position of the measurement piece by a displacement detector of the probe each time the XY stage is moved for a predetermined distance while controlling a driving actuator so that the measurement piece (14) of a probe touches the measurement reference surface at a constant pressure; and calculating a straightness error of a measurement-piece moving mechanism on a basis of a measured position (Zreal) of the measurement piece obtained in the measuring, a nominal position (Znom) of the measurement piece obtained by a calculation and a slant angle (θ) of the measurement reference surface.