Remote Induction Weld Temperature Sensing for Composite Joints
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Solution Overview
Problem
Controlling the temperature during induction welding of thermoplastic composite parts is challenging, leading to potential welds that do not meet desired parameters if not performed within a specific temperature range.
Innovation Solution
The use of remote sensing technologies, such as sensors embedded in a heat sink or fiber optic sensors, to infer weld temperatures non-invasively, allowing for real-time control of the induction welding process without the need for sensors at the weld interface, thereby ensuring accurate temperature monitoring and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are placed directly at the weld interface to monitor temperature, then temperature measurement precision is improved, but weld strength deteriorates and device complexity increases
Solution Approach 1:
The patent uses an intermediary heat sink positioned between the sensor and the weld interface. The heat sink conducts heat from the weld interface to the sensor, enabling temperature measurement without direct sensor contact with the weld zone. This intermediary approach maintains weld strength while providing sufficient temperature measurement precision for process control.
2Measurement precision
If sensors are placed directly at the weld interface to monitor temperature, then temperature measurement precision is improved, but device complexity increases
Solution Approach 1:
The heat sink serves as a simplified intermediary device that enables remote temperature sensing. Instead of requiring complex high-temperature resistant sensors at the weld interface, the system uses a passive heat conducting block that transfers thermal information to standard sensors, significantly reducing device complexity while maintaining adequate measurement precision.
3Strength
If remote sensing is used to monitor weld temperature, then device complexity is reduced and weld strength is improved, but temperature measurement precision deteriorates
Solution Approach 1:
The system implements feedback control where the temperature signal from the remote sensor is fed back to the induction heating controller. This feedback loop allows the system to adjust heating parameters based on the remote temperature reading, compensating for the reduced measurement precision and ensuring the weld interface reaches the required temperature for strong welds.
Solution Approach 2:
The heat sink acts as a thermal intermediary that preserves temperature information from the weld interface and transmits it to the remote sensor. By optimizing the heat sink's thermal conductivity and geometry, the system maintains sufficient temperature measurement precision despite the remote sensing arrangement, while simultaneously protecting the weld interface from sensor interference.
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 enhances weld strength, reduces costs, and ensures that induction welds are performed within desired temperature ranges, improving the consistency and quality of the welding process.
Implementation Method 1
a magnetic coil that generates an alternating magnetic field and projects the field through the parts and around the susceptor
Implementation Method 2
As the susceptor gets hot, its electrical resistance changes as a function of the thermal coefficient of resistance of the susceptor material
Implementation Method 3
sensors embedded in a heat sink to infer weld temperatures
Data Source
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AI summary
Systems and methods are provided for controlling welding. One embodiment is a method for controlling welding. The method includes initiating induction welding by operating an induction coil along a weld interface of a first composite part comprising a matrix of thermoplastic reinforced by fibers, in order to join the first composite part to a second composite part, determining a measured magnetic field strength at a location distinct from the induction coil, and determining a welding temperature at the weld interface of the first composite part based on the measured magnetic field strength.