Coaxial Thermal Radiation Image Evaluating System for Selective Laser Melting
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Solution Overview
Problem
Current methods for monitoring the melting bath status in selective laser melting additive manufacturing are either costly due to the need for high-resolution thermal imagers or require expensive dual-color pyrometers, and fail to accurately determine melting bath temperature, especially under the influence of non-coherent images and thermal imager resolution limitations.
Innovation Solution
An insert coaxial thermal radiation image evaluating system utilizing a conjugate foci framework with a high-sensitivity avalanche photodiode and notch filter, coupled with a scanner and dichroic mirrors, to form images of thermal radiation generated from a high-power infrared laser irradiation zone, allowing for precise temperature measurement and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution thermal imagers are used to capture real-time melting bath images, then measurement precision is improved, but device cost increases significantly
Solution Approach 1:
The patent introduces a beamsplitter as an intermediary optical element that divides the optical path into two channels: one for processing laser observation and another for thermal radiation detection. This allows a standard photodiode to function as a pyrometer by detecting thermal radiation through the beamsplitter, eliminating the need for expensive high-resolution thermal imagers while maintaining measurement precision
Solution Approach 2:
The patent creates an optical copy of the melting bath thermal radiation by using the beamsplitter to redirect a portion of the thermal radiation to the photodiode detector. This optical copying mechanism enables temperature measurement without requiring direct high-resolution thermal imaging, thereby reducing device cost while preserving measurement accuracy
2Measurement precision
If dual-color pyrometers are positioned coaxially to evaluate thermal radiation, then temperature measurement capability is improved, but device cost increases
Solution Approach 1:
The patent segments the optical detection system into two independent channels using a beamsplitter: one channel for processing laser observation and another for thermal radiation detection. This segmentation allows a standard photodiode to perform pyrometer function in the thermal radiation channel, replacing the need for an expensive dual-color pyrometer while maintaining temperature measurement capability
Solution Approach 2:
The patent makes the photodiode detector multi-functional by enabling it to detect both processing laser light and thermal radiation through different optical paths created by the beamsplitter. This universality allows a single, cost-effective detector to replace expensive specialized equipment while maintaining measurement capabilities
3Device complexity
If standard photodiodes are used to detect thermal radiation, then device cost is reduced, but sensing intensity is insufficient
Solution Approach 1:
The patent introduces a beamsplitter as an intermediary that optimizes the optical path for thermal radiation detection. By carefully designing the optical coupling through the beamsplitter, the system maximizes the thermal radiation signal reaching the photodiode, compensating for the photodiode's inherently lower sensing intensity compared to specialized detectors
Solution Approach 2:
The patent optimizes detection parameters including the photodiode's spectral response characteristics and the optical path design to enhance thermal radiation detection efficiency. By adjusting these parameters, the system achieves sufficient sensing intensity with a cost-effective photodiode instead of requiring expensive high-sensitivity detectors
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 system enhances the precision of melting bath status surveillance, improves additive manufacturing efficiency, and reduces costs by using a domestically manufactured metal additive manufacturing framework, while achieving high transverse and vertical resolution imaging.
Implementation Method 1
evaluating thermal radiation emitted from a high-temperature melting bath with a light detector
Implementation Method 2
An insert coaxial thermal radiation image evaluating system utilizing a conjugate foci framework with a high-sensitivity avalanche photodiode and notch filter
Implementation Method 3
coupled with a scanner and dichroic mirrors, to form images of thermal radiation generated from a high-power infrared laser irradiation zone
Implementation Method 4
form images of thermal radiation generated from a high-power infrared laser irradiation zone, allowing for precise temperature measurement
Data Source
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AI summary
An insert coaxial thermal radiation image evaluating system (16) includes a cage support (5), first lens (7), first cage movable frame (9), second cage movable frame (10), cage holder (6) and light detector (13). The first cage movable frame (9) is movably disposed at the cage support (5) and connected to the first lens (7). The second cage movable frame (10) is movably disposed at the cage support (5) and connected to the light detector (13). The cage holder (6) is connected to the cage support (5) to fix the cage support (5) to an optical substrate (11). The first cage movable frame (9) is movably disposed in the cage holder (6). The first lens (7) and a second lens (8) of a metal additive manufacturing system together form a structure of conjugate foci, such that a thermal radiation generated from a high-power infrared laser irradiation zone (18) forms according to a fixed ratio an image captured by the light detector (13).