Electrode Force Sensing Plate for Resistance Welding Control
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Solution Overview
Problem
Existing electric resistance welding machines struggle to accurately measure and control the welding force due to interference from electromagnetic forces and friction, leading to unpredictable oscillations and deviations, especially when repeatability is critical.
Innovation Solution
A welding apparatus with a measurement device comprising a plate and deformation sensors positioned near the weld point, measuring the deformation caused by the welding force directly, independent of the electrode's position, and using an electronic control unit to adjust the force accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are positioned at a considerable distance from the weld point to avoid electromagnetic interference, then the measurement is safer from interference, but the measurement precision deteriorates because friction and other force components cannot be properly considered
Solution Approach 1:
The patent introduces a magnetic shield as an intermediary element between the sensors and the electromagnetic interference source. This shield blocks electromagnetic fields while allowing mechanical force transmission, enabling sensors to be positioned close to the weld point without direct electromagnetic interference. The magnetic shield acts as a mediator that selectively transmits mechanical signals while blocking electromagnetic disturbances.
Solution Approach 2:
The patent replaces traditional mechanical connection methods with magnetic coupling between the sensor assembly and the electrode holder. This magnetic coupling transmits force information without direct mechanical contact, eliminating friction interference while maintaining measurement accuracy. The magnetic field serves as the transmission medium instead of mechanical contact.
2Device complexity
If gauges and pressure regulator valves are used for indirect control, then the device complexity is reduced, but the manufacturing precision deteriorates due to unpredictable variations in friction and electromagnetic forces
Solution Approach 1:
The patent implements a feedback control system where sensors continuously measure the actual welding force and transmit this information to a control unit. The control unit compares the measured force with the target force and automatically adjusts the electrode holder position or pressure to maintain the desired welding force. This closed-loop feedback eliminates the need for complex mechanical pressure regulation mechanisms while ensuring precise force control.
Solution Approach 2:
The patent replaces mechanical pressure regulation valves and gauges with an electronic control system based on sensor feedback. Instead of using mechanical components to indirectly control and measure pressure, the system uses electronic sensors and control algorithms to directly manage the welding force, achieving better precision with simpler mechanical components.
3Manufacturing precision
If force measurement instruments are interposed during production checks, then the manufacturing precision can be verified, but the productivity decreases due to production stoppages
Solution Approach 1:
The patent enables continuous force measurement during welding operations by integrating sensors into the electrode holder assembly. The measurement process occurs simultaneously with the welding process rather than requiring separate inspection steps. This continuous monitoring allows real-time verification of welding force without interrupting production, maintaining both measurement accuracy and manufacturing productivity.
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 provides precise and reliable measurement of welding force, eliminating process uncertainties and ensuring consistent results by compensating for electromagnetic interference and friction-related distortions.
Implementation Method 1
owing to the Joule effect, the current causes the localized heating of the point of contact between the parts and the electrode
Implementation Method 2
the flow of current between the electrodes produces an electromagnetic force contrary to the direction of the force applied
Data Source
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AI summary
A welding apparatus, which comprises a movement assembly (2) for at least one electrode, which can be passed through by current for the execution of welding treatments. The assembly (2) comprises at least one cylinder (3) and at least one stem (4) which rigidly supports the electrode; the stem (4) is at least partially accommodated in the cylinder (3) and is coaxially movable with an alternating straight motion along the longitudinal axis (A) of the cylinder (3), in order to press the electrode against the parts to be welded with a corresponding welding force. The apparatus comprises a device (6) for measuring the welding force, which comprises a plate (7), which is stably interposed between the stem (4) and the electrode with the respective faces (7a, 7b) arranged at right angles to the longitudinal axis (A), and a plurality of deformation sensors (8), which are accommodated in through slots (9) provided in the plate (7) and distributed along an imaginary circumference (B) which is centered along the longitudinal axis (A).