Induction-Heated CFRTP Fastener Forming for Faster Joining
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Solution Overview
Problem
Existing fastening methods using fiber-reinforced resin fasteners require heating both fastener-forming dies to high temperatures, leading to prolonged cooling times and slower fastening processes.
Innovation Solution
A fastening apparatus utilizing induction heating with high-frequency induction coils to locally heat carbon fiber-reinforced thermoplastic resin shafts, allowing for rapid formation of reinforced head and shaft parts without the need for high-temperature dies, thus speeding up the fastening process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If both fastener-forming dies are heated to high temperatures to form the fastener, then the shaft body can be heated to a plastically deformable softened state, but the cooling time becomes excessively long and productivity decreases
Solution Approach 1:
The heating function is segmented from the fastener-forming dies and transferred to a dedicated induction heater. This allows the dies to remain at room temperature while only the shaft body is heated locally, eliminating the need to cool large heated die surfaces and significantly reducing cycle time.
Solution Approach 2:
The thermal field is substituted from contact-based die heating to induction heating. The induction heater uses electromagnetic induction to heat the shaft body directly without requiring the dies to be heated, replacing the thermal-mechanical coupling system with a more efficient electromagnetic heating system.
2Temperature
If both fastener-forming dies are heated to high temperatures, then the shaft body can be formed into a fastener, but energy consumption increases due to maintaining high temperature for extended periods
Solution Approach 1:
Heating is localized to only the shaft body where it is needed for forming, rather than heating the entire fastener-forming die system. The induction heater applies heat precisely to the shaft body's outer peripheral surface, maintaining high temperature only where required for plastic deformation while keeping other components at ambient temperature.
Solution Approach 2:
The induction heater operates periodically only during the heating phase of the cycle, rather than continuously maintaining high temperature. The heater is activated to heat the shaft body, then deactivated while the forming process completes using the retained heat, reducing overall energy consumption compared to continuous die heating.
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
Enables rapid and secure fastening of workpieces with carbon fiber-reinforced resin fasteners by locally heating the shafts, reducing overall processing time and maintaining the integrity of the fastener components.
Implementation Method 1
a shaft-body heater adapted to heat a shaft of an initial piece... a shaft-part heater adapted to heat only the shaft... by induction heating
Data Source
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AI summary
A fastening method and a fastening apparatus are provided in which the work of fastening a plurality of workpieces using a fastener made of a fiber-reinforced resin can be performed rapidly. A fastening method of the present invention comprises: a preparing process that prepares an intermediate piece 111, which is made of a fiber-reinforced resin and comprises a first head part 11a and a shaft part 11b formed integrally with the first head part 11a and extending in an axial direction; a shaft-part heating process that heats the shaft part 11b in a noncontacting state while the shaft part 11b is inserted through each of the through holes W10, W20 of each of the workpieces W1, W2; and a fastening process that forms a second head part 11b opposing the first head part 11a using a fastening die 17 and thereby fastens the workpieces W1, W2 using the intermediate piece 111 as the fastener 11by applying pressure to the heated shaft part 11b in the state in which the shaft part 11b is inserted through each of the through holes W10, W20 of each of the workpieces W1, W2. The fiber-reinforced resin is a carbon-fiber-reinforced thermoplastic resin. The shaft-part heating process is performed by a high-frequency induction coil capable of induction heating 3b.