Induction-Heated Resin Fastener Forming With Load-Curve Defect Detection
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Solution Overview
Problem
Existing fastening apparatuses using fiber-reinforced resin fasteners require high temperatures for deformation, leading to prolonged cooling times and increased risk of defects, making rapid and high-quality fastening challenging.
Innovation Solution
A fastening apparatus that heats the shaft part in a non-contacting state using a high-frequency induction coil, allowing for quick formation of fasteners and incorporating a determining device to assess load curves for defect detection, enabling rapid and high-quality fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If both fastener-forming dies are heated to high temperature to deform the shaft body, then the shaft body can be plastically deformed into a fastener, but the cooling time becomes excessively long
Solution Approach 1:
The patent extracts the heating function from the fastener-forming dies and assigns it to a separate induction heating device. This allows the dies to remain at room temperature while the shaft body is heated independently, eliminating the cooling time penalty associated with heating the entire die system.
Solution Approach 2:
The patent replaces the thermal field-based heating method (heating the dies) with an electromagnetic field-based induction heating method. This substitution enables rapid and localized heating of the shaft body without requiring the mechanical/thermal mass of the dies to be heated, thus dramatically reducing cooling time.
2Manufacturing precision
If high temperature is maintained for a long time to ensure complete deformation, then the fastener formation is thorough, but defects may occur and quality control becomes difficult
Solution Approach 1:
The patent introduces a load curve detection system that provides real-time feedback during the fastening process. By monitoring the load curve characteristics, the system can detect anomalies indicating defects and distinguish them from normal process variations, enabling quality control without requiring excessive heating time.
Solution Approach 2:
The patent changes the heating parameters from prolonged high-temperature heating to controlled induction heating with specific temperature and time parameters. This optimized heating regime achieves complete deformation while minimizing the risk of thermal defects.
3Productivity
If non-contact induction heating is used to heat the shaft part, then heating efficiency and speed are improved, but additional equipment complexity is introduced
Solution Approach 1:
The patent replaces contact-based heating methods with non-contact induction heating, which uses electromagnetic fields to directly heat the shaft part. This substitution improves heating efficiency and speed while the modular design of the induction heating device keeps the added complexity manageable.
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 apparatus enables rapid fastening of workpieces with fiber-reinforced resin fasteners by reducing cooling time and facilitating defect detection, thereby improving the quality and efficiency of the fastening process.
Implementation Method 1
heats the shaft part in a non-contacting state using a high-frequency induction coil
Data Source
AI summary
A fastening apparatus includes a fastening device (1, 3) that heats in a non-contacting state, and then applies pressure to, a shaft part (11b) or shaft body (111) while it is inserted through the through holes (W10, W20) of workpieces (W1, W2), thereby forming at least a second head part (11c) of a fastener (11). The fastening device (1, 3) includes: a fastening die (15) that forms the second head part (11c); and a shaft-part pressure-applying device (9) that applies the pressure to the fastening die (15). A determining device (5) determines whether the fastener (11) is defective or not by calculating a load curve defined by the time and the load during which the pressure was applied and then determining whether an amount of change per unit of time in the load curve after a reference load has been exceeded is within a range of a predetermined reference value.