Calibrating Surface Texture Measurement Device Stylus Offset
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Solution Overview
Problem
Surface texture measurement devices with upward and downward styluses face challenges in accurately evaluating the mutual relationship between measurement results due to uncertainties in the positional relationship of the styluses, leading to inaccuracies in measuring thickness and internal diameter of cylindrical workpieces.
Innovation Solution
A method for calibrating surface texture measurement devices by obtaining shape measurement data from a reference sphere using both styluses and calculating offset amounts to establish an accurate positional relationship between the upward and downward styluses, allowing for precise correction of measurement errors and evaluation of measurement results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If both upward and downward styluses are provided to measure upper and lower surfaces without removal and attachment, then measurement time is reduced and productivity is improved, but measurement precision deteriorates due to inaccurate mutual positional relationship between the styluses
Solution Approach 1:
The patent applies preliminary action by performing calibration measurement before actual measurement to establish the mutual positional relationship between upward and downward styluses. The calibration process uses a reference sphere to determine offset amounts, which are stored and applied during subsequent measurements, ensuring precision is established in advance rather than during the measurement process itself.
Solution Approach 2:
The patent uses a reference sphere as an intermediary object to establish the positional relationship between the two styluses. The reference sphere provides a known geometric standard that mediates the calibration process, allowing the system to accurately determine offset amounts without requiring direct comparison between the styluses themselves.
2Measurement precision
If offset amounts are calculated based on center coordinates from shape measurement data, then measurement precision is improved, but device complexity increases due to additional calibration procedures
Solution Approach 1:
The system performs self-calibration by automatically calculating offset amounts from measurement data of a reference sphere. The calibration process is automated, with the system itself determining its own positional parameters through mathematical calculation of center coordinates, rather than requiring manual adjustment or external intervention.
Solution Approach 2:
The patent changes parameters by calculating and applying offset amounts that adjust the positional relationship between styluses. These parameter changes are derived from the difference in center coordinates obtained from upper and lower surface measurements, allowing the system to adapt its measurement parameters based on actual geometric data.
Data Source
AI summary
A method of calibrating a surface texture measurement device includes obtaining Y-axis shape measurement data and a maximum diameter portion to obtain upper and lower maximum diameter portions of a reference sphere from Y-axis upper and lower shape data obtained by relatively moving in the Y-axis direction while a downward and an upward styluses are in contact with an upper and a lower surfaces, respectively, of the reference sphere; obtaining X-axis shape measurement data to obtain X-axis upper and lower shape data of the reference sphere by relatively moving in the X-axis direction while the downward stylus is in contact with the upper diameter portion and the upward stylus with the lower diameter portion of the reference sphere; and calculating offset amounts Δx and Δz of the upward and downward styluses from center coordinates O3 and O4 obtained from the shape data.