Micro-vibration Sensor with Crack-tip Piezoelectric Film
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Solution Overview
Problem
Current vibration sensors in ultra-precision machining environments have low measurement accuracy, which affects the surface quality of workpieces at a micron-level/nano-level.
Innovation Solution
A micro-vibration sensor is prepared by coating a first curing material onto a thin metal sheet, curing it, sticking a piezoelectric thin film element onto the edge, placing it in a second curing material, and removing the metal sheet to create a crack with the piezoelectric element at the tip, amplifying stress signals into electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional vibration sensor is used in ultra-precision machining environment, then the device structure is simple, but the measurement accuracy is low
Solution Approach 1:
The patent applies local quality by creating a crack tip region with highly concentrated stress field. The piezoelectric thin film is specifically positioned at the crack tip where stress is most concentrated, allowing localized high-sensitivity detection without requiring the entire sensor structure to be complex. This localized stress concentration approach enables high measurement accuracy while keeping the overall device structure relatively simple.
Solution Approach 2:
The patent replaces conventional mechanical vibration sensing with piezoelectric effect-based sensing. The piezoelectric thin film converts mechanical stress directly into electrical signals, substituting traditional mechanical measurement mechanisms with a more sensitive electromechanical conversion system. This substitution dramatically improves measurement accuracy for micro-vibrations in ultra-precision machining.
2Measurement precision
If the piezoelectric thin film element is positioned at the crack tip, then the detection sensitivity is high, but the manufacturing precision requirement is high
Solution Approach 1:
The patent applies preliminary action by pre-forming the crack structure and determining the stress concentration region before positioning the piezoelectric thin film. The crack is created first, establishing the near-tip stress field distribution, and then the piezoelectric element is positioned in this predetermined high-stress region. This sequence ensures optimal positioning without requiring extremely high manufacturing precision during the film attachment process.
Solution Approach 2:
The crack structure serves as an intermediary that naturally concentrates stress to a specific region. Instead of requiring precise direct positioning of the piezoelectric film on a flat surface, the crack acts as a stress-focusing intermediary that guides and amplifies mechanical stress to the film location, tolerating some variation in positioning while maintaining high detection sensitivity.
3Ease of operation
If a thin metal sheet is used as substrate, then the sensor is flexible and easy to install, but the structural strength is low
Solution Approach 1:
The patent creates a composite structure combining thin metal sheet substrate with cured layer and piezoelectric thin film. The thin metal sheet provides flexibility and ease of installation, while the cured layer (epoxy resin or similar material) provides structural support and strength. This composite construction allows the sensor to maintain both flexibility for easy installation and sufficient structural strength for durable operation in machining environments.
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 measurement accuracy and detection sensitivity by dramatically magnifying stress signals at the crack tip, resulting in a low detection limit and high precision.
Implementation Method 1
sticking a piezoelectric thin film element onto an edge of the first cured layer
Implementation Method 2
the crack deforms under a force, causing a stress at the near-tip stress field of the crack to get magnified dramatically
Data Source
AI summary
A micro-vibration sensor and preparation method thereof. The method includes a metal sheet is coated with first curing material, and first curing material is cured into first cured layer; piezoelectric thin film element is attached to edge of first cured layer; one side, attached with piezoelectric thin film element, of first cured layer is vertically placed into second curing material, and second curing material is cured into second cured layer; and metal sheet is removed to obtain micro-vibration sensor. Due to fact that piezoelectric thin film element is arranged at a crack tip, during micro-vibration, stress in stress field of crack tip is rapidly increased due to crack stress deformation, and stress signal is efficiently converted into electric signal; and micro-vibration sensor has characteristics of being low in detection limit and high in accuracy.