Friction Current Joining with Conductive Heating and Low Pressing Force
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Solution Overview
Problem
Conventional friction welding processes often result in fiber distortions and hardening in the joining zone, and require high mechanical stress on the welding machine due to the need for a friction phase with high contact pressure and relative movement.
Innovation Solution
The process involves a multi-stage approach with an approximation phase, a subsequent phase, and a compact phase with electrical conductive warming, eliminating the need for a high-pressure friction phase. Workpieces are heated and plastified using conductive electrical heating, allowing for joining under lower contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional friction welding with high contact pressure and friction phase is used, then joining strength is achieved, but fiber distortions and hardening occur in the joining zone
Solution Approach 1:
The patent replaces the conventional mechanical friction heating system with an electrical heating system. Instead of relying on high contact pressure and frictional movement to generate heat, the invention uses electrical current passed through the workpieces to generate heat directly at the joining interface. This substitution eliminates the need for high mechanical stress while achieving the required plasticization and bonding, thereby preventing fiber distortions and hardening in the joining zone.
Solution Approach 2:
The patent fundamentally changes the heating parameter from mechanical friction (conventional method) to electrical current (invention). By changing the heating mechanism from friction-based to electrical-based, the process achieves plasticization without requiring high contact pressure and relative movement, thus avoiding the harmful effects of fiber distortion and material hardening while maintaining joining strength.
2Temperature
If friction phase with high contact pressure and relative movement is used, then plasticization is achieved, but mechanical stress on the welding machine increases significantly
Solution Approach 1:
The patent replaces the mechanical friction system with an electrical heating system. The electrical current generates heat directly at the joining interface through resistive heating, eliminating the need for high contact pressure and frictional movement. This substitution dramatically reduces the mechanical stress on the welding machine while achieving the necessary plasticization temperature for bonding.
Solution Approach 2:
The workpieces themselves serve as the heating element by conducting electrical current through them. The electrical resistance of the workpiece material converts electrical energy directly into thermal energy at the joining interface, eliminating the need for external mechanical friction or separate heating devices. This self-heating mechanism achieves plasticization without imposing high mechanical loads on the equipment.
3Reliability
If conventional friction welding process is used, then joining is achieved, but energy consumption is high due to friction phase requirements
Solution Approach 1:
The patent replaces the energy-intensive mechanical friction process with a more efficient electrical heating process. Electrical current directly converts to heat at the joining interface through resistive heating, which is more energy-efficient than generating heat through friction. This substitution maintains joining quality while significantly reducing overall energy consumption by eliminating the need for high-speed rotation and sustained high contact pressure.
Solution Approach 2:
The patent skips the lengthy friction phase required in conventional welding by directly applying electrical heating to achieve plasticization. Instead of gradually heating through prolonged friction, the electrical current rapidly generates the necessary heat at the joining interface, reducing process time and energy consumption while achieving the same bonding quality.
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 achieves a high reproducibility and quality of the joining process with reduced mechanical stress on the machine, lower energy requirements, and minimized fiber distortions and hardening in the joining zone.
Implementation Method 1
the workpieces are instead heated and plasticized by conductive electrical heating
Implementation Method 2
heated and plasticized by conductive electrical heating
Data Source
Figure 1
Figure 2~5
Figure 6
AI summary
The invention relates to a method and an apparatus for friction current joining, the friction current joining apparatus (1) having a friction device (7), a compressing device (8), an electrical current source (16) and a programmable controller (24), as well as workpiece receptacles (14, 15) for the workpieces (2, 3) to be joined. The friction current joining apparatus (1) is controlled in such a way that the workpieces (2, 3) are first brought into contact with the joining surfaces (4, 5) thereof, which face each other, in an approach phase (a), and then, in a friction phase (b), the joining surfaces (4, 5) thereof are rubbed against each other and leveled under a pressing pressure (p) by mutual relative movement, wherein the rubbing relative movement is subsequently permanently ended and, in a compression phase (c), the contacting joining surfaces (4, 5) of the workpieces (2, 3) are pressed together, plasticized and joined under a pressing pressure (p) and under conductive heating by means of electrical current (I).