AC Bridge Surface Inspection Device
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Solution Overview
Problem
Existing surface property inspection methods for materials subjected to treatments like shot-peening and heat treatment face challenges in accurately measuring surface properties non-destructively, particularly due to environmental changes such as temperature variations, which can lead to measurement errors and lack of calibration methods to account for these errors.
Innovation Solution
A surface property inspection device utilizing an AC bridge circuit with a variable resistor and a reference detector to compare output signals from an inspection detector and a reference test object of the same structure, allowing for high-precision evaluation of surface properties by canceling out fluctuations caused by environmental changes like temperature, humidity, and magnetism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic measurement is performed to inspect surface treatment state, then non-destructive inspection is achieved, but measurement errors arise due to environmental changes such as temperature variations
Solution Approach 1:
The patent uses a reference test object that is a copy of the actual test object in terms of structure, material, and dimensions, but without surface treatment. This reference object experiences the same environmental conditions (temperature, humidity, magnetism) as the test object, allowing the system to measure and compensate for environmental effects by comparing the electromagnetic properties of both objects. The bridge circuit measures the difference between the reference and test objects, effectively canceling out environmental measurement errors.
2Ease of manufacture
If reference test object measurement is performed in different environments, then calibration is simplified, but measurement errors increase due to environmental differences
Solution Approach 1:
The patent performs preliminary calibration by measuring the reference test object under the same environmental conditions as the actual inspection. The bridge circuit is adjusted to establish a baseline measurement before the actual test object is inspected. This preliminary action ensures that any environmental effects present during calibration are accounted for, and the same environmental conditions are maintained during actual measurement, thereby preventing measurement errors while maintaining calibration simplicity.
3Ease of operation
If bridge circuit output signal is directly used for evaluation, then inspection process is simplified, but measurement accuracy decreases due to environmental fluctuations
Solution Approach 1:
The patent implements a feedback mechanism where the bridge circuit continuously compares the electromagnetic properties of the reference test object and the test object. The output signal represents the difference between these two measurements, providing real-time feedback on environmental effects. This feedback is used to compensate for environmental fluctuations, maintaining measurement accuracy while keeping the inspection process simple through automated compensation rather than manual correction.
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
This method enables accurate and precise non-destructive inspection of surface properties by stabilizing measurements against environmental changes, improving measurement accuracy and allowing for the setting of appropriate threshold values, thus ensuring reliable evaluation of surface treatment states.
Implementation Method 1
an inspection detector comprising a coil capable of exciting AC magnetism and formed so that said coil excites an eddy current in the test object
Implementation Method 2
said coil excites an eddy current in the test object
Implementation Method 3
a reference detector constituted to excite the eddy current in a reference test object having the same structure as the test object for detecting a reference state
Data Source
Figure 1(A)
Figure 1(B)
Figure 2
AI summary
To provide a surface property inspection device and method capable of inspecting the surface treatment state of treated material subjected to surface treatments. A surface property inspection device 1 includes an AC power supply 10, an AC bridge circuit 20, and an evaluation apparatus 30, and the AC bridge circuit 20 is formed by a variable resistor 21 with a distribution ratio of γ, a reference detector 22, and an inspection detector 23. The inspection detector 23 includes a coil 23b wound so as to oppose the surface property inspection area of the test object M; an eddy current is excited in the test object M by supplying AC power to the coil 23b. A reference test object S with the same structure as the test object M is placed in the reference detector 22 to cancel inspection environment effects.