Bond Test Jaw Force Measurement Using Flexure Displacement
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Solution Overview
Problem
Existing bond test apparatuses lack precise control over the closing force applied by test tool jaws and provide inadequate feedback, leading to inconsistent bond strength measurements due to the use of pneumatic actuators and complex, expensive motor-driven systems.
Innovation Solution
A bond test apparatus utilizing a flexure coupled with a displacement sensor, such as a Hall effect sensor, to measure the displacement of the flexure and calculate the force applied to the jaws, eliminating the need for strain gauges and providing accurate, consistent force measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are mounted on flexures to measure force, then force measurement capability is achieved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent replaces the mechanical strain gauge mounting system with a magnetic field-based measurement system. A magnet is attached to the moving component and a Hall effect sensor detects its position, eliminating the need to mechanically mount strain gauges on flexures. This substitution resolves the contradiction by achieving force measurement through magnetic field detection rather than mechanical strain sensing.
Solution Approach 2:
The patent introduces a magnet as an intermediary element that couples the mechanical movement to the sensing system. Instead of directly measuring strain on the flexure, the magnet's movement in response to applied force is detected by the Hall effect sensor. This intermediary approach simplifies the measurement system while maintaining measurement capability.
2Ease of operation
If pneumatic actuators are used to close test tool jaws, then jaw closing capability is achieved, but control precision and feedback capability deteriorate
Solution Approach 1:
The patent implements a feedback system where the Hall effect sensor continuously monitors the position of the magnet attached to the moving component. This position information is fed back to the control system, enabling precise control of jaw closing force. The feedback mechanism resolves the contradiction by providing real-time measurement data that allows precise control of the jaw closing operation.
Solution Approach 2:
The patent replaces the pneumatic actuation system with an electric motor-driven system coupled to a lead screw mechanism. This substitution enables more precise control of jaw closing force through electrical control and mechanical advantage, while the integrated Hall effect sensor provides accurate feedback on the actual force applied.
3Measurement precision
If motor-driven systems with strain gauges are used to control closing force, then force control capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the force measurement function from the motor-driven system itself and implements it separately using a Hall effect sensor and magnet combination. Instead of relying on strain gauges mounted on the motor or drive mechanism, the measurement is performed independently on the moving component. This extraction simplifies the overall system while maintaining precise force control capability.
Solution Approach 2:
The patent substitutes the strain gauge-based measurement system with a magnetic field-based measurement system. The Hall effect sensor detects the position of the magnet, which moves in response to applied force, providing a simpler and more reliable measurement method that eliminates the complexity of mounting and calibrating strain gauges on motor-driven components.
4Measurement precision
If strain gauges are used for force measurement, then force measurement capability is achieved, but long-term precision and reliability deteriorate due to creep
Solution Approach 1:
The patent replaces the mechanical strain gauge system with a magnetic field-based measurement system using a Hall effect sensor. The magnet's position is detected through magnetic field changes rather than mechanical strain, eliminating the creep phenomenon that affects strain gauges over time. This substitution resolves the contradiction by providing a measurement system that maintains long-term precision and reliability without the degradation issues of mechanical strain sensing.
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 achieves precise control over the closing force and improved accuracy in bond strength measurements by using displacement sensors, reducing creep and maintaining high precision without the limitations of strain gauges.
Implementation Method 1
The sensor is a Hall effect sensor and one of the magnet or the sensor is fixed to, or fixed relative to, a first end of the flexure, while the other of the magnet or the sensor is fixed relative to a second end of the flexure
Implementation Method 2
a flexure (380), coupled to the test tool assembly (11, 410), wherein one of the magnet or the sensor is fixed to, or fixed relative to, a first end of the flexure (380), while the other of the magnet or the sensor is fixed relative to a second end of the flexure (380)
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
A bond test apparatus (200, 350) comprises: a test tool assembly, the test tool assembly comprising a test tool configured to contact a bond (101) during a bond test; a flexure (80, 380) coupled to the test tool assembly; a displacement sensor (220, 425); and a detectable member (110, 415). One of the detectable member and the displacement sensor is fixed relative to a first end of the flexure and the other is fixed relative to a second end of the flexure. The displacement sensor is not a strain gauge. The displacement sensor is configured to detect a displacement between the displacement sensor and the detectable member, so that the displacement sensor provides a measurement of a displacement of the first end of the flexure relative to the second end of the flexure on application of a force to the flexure. The bond test apparatus comprises a processor configured to receive a displacement signal from the displacement sensor and to determine the force on the flexure using the displacement signal. A cartridge for a bond test apparatus, a method of measuring a force in a bond test apparatus, and a method of measuring the closing force on the jaws of a bond test tool are also provided.