Induction Softening for Resin-Metal Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for joining resin and metal members, such as screw fastening, rivet punching, and adhesion, face challenges like laborious processes, potential cracking, and difficulty in maintaining waterproofness and airtightness, particularly when rigid members are involved.
Innovation Solution
A joining device and method that uses high-frequency induction heating to soften the resin member before press-fitting a fastener, followed by resistance welding to join the resin and metal members without pre-drilling, ensuring a strong and crack-free bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screw fastening is used to join resin and metal members, then the joining strength is improved, but the process becomes laborious due to pre-drilling requirements and waterproofness deteriorates
Solution Approach 1:
The resin member is pre-heated by induction heating before the fastener is inserted, softening the resin in advance to facilitate easy insertion without pre-drilling holes. This preliminary softening action eliminates the need for complex pre-drilling operations while maintaining joining strength.
Solution Approach 2:
The traditional mechanical pre-drilling process is replaced by thermal softening through induction heating. Instead of mechanically removing material to create holes, the resin is heated to a softened state allowing the fastener to be inserted directly, simplifying the manufacturing process and maintaining waterproofness.
2Ease of manufacture
If rivet punching is used to join resin and metal members, then the manufacturing process is simplified by eliminating pre-drilling, but cracking occurs in rigid resin members
Solution Approach 1:
The resin member is pre-heated by induction heating before the fastener is inserted, softening the resin in advance to make it more ductile and resistant to cracking during the punching process. This preliminary thermal treatment eliminates cracks in rigid resin members while maintaining manufacturing simplicity.
Solution Approach 2:
The physical state of the resin is changed from rigid to softened by controlling the temperature through induction heating. This parameter change (temperature increase) allows the fastener to be inserted without causing cracks, while the resin remains in a controlled softened state that prevents damage.
3Ease of manufacture
If adhesion is used to join resin and metal members, then pre-drilling is eliminated and the process is simplified, but processing time increases due to curing requirements
Solution Approach 1:
The chemical adhesion process requiring curing time is replaced by a mechanical insertion process using thermally softened resin. Instead of applying adhesive and waiting for chemical curing, the resin is heated and the fastener is inserted directly, eliminating the time-consuming curing step while maintaining process simplicity.
4Ease of operation
If a metal fastener is press-fit into rigid resin without heating, then the joining process is simple, but cracking or fissures occur in the resin member
Solution Approach 1:
The temperature of the resin is increased through induction heating, changing its physical properties from rigid and brittle to softened and more ductile. This parameter change allows simple press-fitting operations without causing cracking or fissures, as the softened resin can deform to accommodate the fastener insertion.
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 approach eliminates the need for pre-drilling and reduces the likelihood of cracking, enabling a simple and high-strength joining of resin and metal members while maintaining waterproofness and airtightness.
Implementation Method 1
a high-frequency induction coil (36) disposed on the outside of the nose piece (30) tip; a high-frequency induction output device (56) into which high-frequency current is input from the chopper device (52), and from which high-frequency induction current is sourced to the high-frequency induction coil (36); the fastener (10) is heated by high-frequency induction heating
Implementation Method 2
a resistance welding output device (55) into which the high-frequency current is input from the chopper device (52), and a welding current is sourced between the electrode punch (31) and the metal member (42); the fastener (10) and metal member (42) are welded by resistance welding
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
When a metal member (42) and a resin member (41) are to be joined using a fastener (10) made of metal, damage to the resin member is made less liable to occur, and joining is effected simply and securely, by providing: a cylindrical nosepiece (30) made from an insulator; a high-frequency induction coil (36) which is wound around the nosepiece (30); an electrode punch (31) comprising an electrical conductor, for pushing the fastener (10) into the resin member; a chopper device (52) which converts an alternating current into a high-frequency current; a high-frequency induction output device (56) which causes a high-frequency current to flow through the high-frequency induction coil; a resistance welding output device (55) which causes a welding current to flow between the electrode punch (31) and the metal member; a contact detecting device (54) which detects whether a distal end portion of the fastener that has been pushed into the resin member has come into contact with the metal member; a switching device (53) which is switched, on the basis of the detection result from the contact detecting device (54), in such a way that either the high-frequency induction output device or the resistance welding output device is connected; and a control device (51).