Photoacoustic Defect Detection in Plastic Encapsulated Components
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Solution Overview
Problem
Current methods for detecting internal defects in plastic encapsulated components, such as X-ray and ultrasonic detection, are either costly, harmful, or cause secondary damage, and lack sufficient sensitivity and resolution to identify defects like delamination.
Innovation Solution
A photoacoustic detection method using a nanosecond laser source and ultrasonic probe to extract and analyze time-domain waveforms, determining defect locations and types by comparing waveforms at different surface locations, with ultra-pure water as a coupling agent to avoid secondary damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic detection technology is used, then detection sensitivity to air defects is improved, but the object needs to be soaked in coupling agent requiring subsequent drying to avoid secondary damage
Solution Approach 1:
The patent replaces the traditional mechanical ultrasonic detection system with a photoacoustic detection system. The photoacoustic effect uses laser-induced acoustic waves instead of mechanical ultrasonic waves, eliminating the need for coupling agents and subsequent drying processes. This substitution maintains high detection sensitivity while avoiding the harmful effects of coupling agent immersion and drying on the plastic component.
Solution Approach 2:
The patent changes the detection parameter from mechanical ultrasonic waves to photoacoustic waves generated by laser irradiation. This parameter change allows detection without requiring the object to be soaked in coupling agents, thereby avoiding the secondary damage from immersion and drying while maintaining high detection sensitivity for air defects.
2Measurement precision
If X-ray detection technology is used, then detection rate for volume defects is improved, but the method is costly and harmful to the human body
Solution Approach 1:
The patent replaces the ionizing radiation-based X-ray detection system with a photoacoustic system that uses laser-induced acoustic waves. This substitution eliminates the harmful radiation exposure to the human body while maintaining the ability to detect volume defects such as pores and inclusions with high detection rates.
Solution Approach 2:
The patent converts the harmful ionizing radiation of X-ray into beneficial photoacoustic waves generated by laser irradiation. The photoacoustic effect transforms optical energy into acoustic energy, creating a non-harmful detection mechanism that maintains high detection rates for volume defects without the health risks associated with X-ray exposure.
3Strength
If ultrasonic detection technology is used, then penetration ability is improved, but imaging resolution is low
Solution Approach 1:
The patent replaces the traditional ultrasonic detection system with a photoacoustic system that combines the penetration ability of acoustic waves with the high resolution of optical focusing. The photoacoustic effect allows for strong focusing of the laser spot, achieving lateral resolution of about 1 μm to 100 μm, which is significantly higher than conventional ultrasonic imaging resolution while maintaining good penetration through the plastic material.
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 method provides non-destructive, real-time, and high-sensitivity detection of internal defects, avoiding secondary damage and offering simple operation with accurate defect location, size, and type determination.
Implementation Method 1
Photoacoustic detection technology based on the photoacoustic effect is a new type of non-destructive testing technology, its basic principle is that when periodic modulated light or pulsed light is irradiated on the material to be tested, the material to be tested absorbs light energy and is periodically heated to produce pressure waves, that is, photoacoustic signals.
Data Source
AI summary
A detection method for internal defects of plastic encapsulated components includes the following steps: pretreatment of plastic encapsulated components; photoacoustic signal acquisition; time domain waveform extraction, and analysis. In the detection method for internal defects of plastic encapsulated components, the photoacoustic image of different plastic encapsulated components is measured by the photoacoustic detection system based on the photoacoustic effect, and the time-domain waveforms at different positions of plastic encapsulated components along the laser and ultrasonic propagation directions are extracted. By analyzing the position, shape, and strength characteristics of the reflection peak of the time-domain waveform, the identification, positioning, and defect type analysis of the internal defects of plastic encapsulated components are realized, the photoacoustic effect is used to distinguish the defect area and defect type inside the plastic encapsulated components, which provides a new method for the non-destructive testing of the internal defects of plastic encapsulated components.