Shape Measuring Arm with Dual Detectors for Contour and Roughness
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Solution Overview
Problem
Conventional shape measuring machines face challenges in accurately measuring both contour shapes over a wide range and minutely uneven surfaces with high responsivity and resolution, due to issues with stylus trackability, complexity, and high costs, as well as limitations in simultaneous measurements using differential transformer and scale type displacement mechanisms.
Innovation Solution
A shape measuring machine design featuring an arm with a stylus at one end and displacement sensors and scale detectors at the other, mounted closer to the fulcrum, allowing for improved stylus trackability and accurate measurement of minute irregularities, while maintaining low costs and high sensitivity, using differential transformer, capacitive, or eddy-current sensors, and an arc-shaped scale detector for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a digital scale is mounted near the stylus on the arm, then wide-range measurement capability is achieved, but the stylus trackability of irregularities deteriorates due to added weight
Solution Approach 1:
The measurement system is segmented into two independent detection paths: one for wide-range contour measurement (scale detector at the other end of the arm) and one for high-precision surface roughness measurement (displacement sensor near the stylus). This segmentation allows each detector to be optimized for its specific function without compromising the other, resolving the contradiction between measurement range and measurement precision.
2Adaptability or versatility
If both a displacement sensor and a scale detector are used to measure arm displacement, then simultaneous contour and surface roughness measurement is enabled, but device complexity increases
Solution Approach 1:
The arm structure serves multiple functions: it supports both the stylus for physical contact measurement and hosts both the displacement sensor and scale detector for dual-mode detection. The arm itself becomes a universal platform that enables both contour shape measurement (via scale detector) and surface roughness measurement (via displacement sensor) simultaneously, reducing overall system complexity despite the dual detector configuration.
Solution Approach 2:
The arm acts as an intermediary element that translates stylus movements into detectable signals for both the displacement sensor and scale detector. By using the arm as a common mechanical intermediary, the system achieves simultaneous measurement capability without requiring separate independent measurement systems, thereby controlling device complexity.
3Length of stationary object
If the support is moved up and down by a servo mechanism, then wide-range measurement is achieved, but apparatus complexity and cost increase
Solution Approach 1:
Instead of moving the support up and down using a servo mechanism, the invention inverts the approach by keeping the support fixed and allowing the arm to rotate freely about the fulcrum. The stylus naturally follows the surface contours through gravitational force and elastic deformation, eliminating the need for complex servo mechanisms while maintaining wide-range measurement capability through the rotational movement of the arm.
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
The machine achieves accurate measurement of both wide-range contour shapes and minutely uneven surfaces with improved stylus trackability and sensitivity, maintaining low costs and high sensitivity, enabling precise surface roughness and contour shape measurement.
Implementation Method 1
The displacement sensor is a differential transformer sensor
Implementation Method 2
The displacement sensor is a capacitive sensor
Implementation Method 3
The displacement sensor is an eddy-current sensor
Data Source
Figure 1~2
Figure 3(A)~4
Figure 5~6
AI summary
The present invention relates to a shape measuring machine (100) for measuring a contour and a roughness shape of a surface of a to-be-measured object, comprising: an arm (106) configured to rotate with a support unit (102) as a fulcrum (104); a stylus (110) configured to be brought into contact with the to-be-measured object, be displaced up and down following a surface shape of the to-be-measured object, and be mounted at one end of the arm (106); and a displacement sensor (112) and a scale detector (114) which at provided at the arm (106) to detect displacement of the arm (106) by displacement of the stylus (110), wherein the shape measuring machine (100) further comprises a correction processing unit (1570) configured to correct data of the displacement sensor (112) by data of the scale detector (114).