Melt Pool Imaging Using Algebraic Connectivity for AM Control
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Solution Overview
Problem
Additive manufacturing machines operate in an open loop environment, lacking real-time feedback on process stability, leading to undetected issues that result in scrapped work in progress.
Innovation Solution
Implement a method of imaging the melt pool during the manufacturing process and extracting its algebraic connectivity to monitor and control the process in real-time, using imaging apparatus and algebraic connectivity analysis to determine the quality of the melt pool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If real-time melt pool monitoring is implemented using algebraic connectivity, then process stability and workpiece quality are improved, but device complexity and measurement difficulty increase
Solution Approach 1:
The patent implements real-time feedback control by continuously monitoring melt pool characteristics through imaging systems and using algebraic connectivity metrics to assess process stability. The system provides immediate feedback on melt pool quality, enabling dynamic adjustment of process parameters to maintain optimal manufacturing conditions throughout the additive manufacturing process.
Solution Approach 2:
The patent replaces traditional mechanical or contact-based measurement methods with optical imaging and computational analysis. By using imaging apparatus to capture melt pool characteristics and applying algebraic connectivity calculations to the image data, the system achieves non-contact, real-time monitoring that avoids mechanical interference with the manufacturing process.
2Device complexity
If open loop operation is used, then device complexity is reduced, but process stability and reliability deteriorate
Solution Approach 1:
The patent transforms the open-loop system into a closed-loop system by implementing real-time monitoring of melt pool characteristics and feeding this information back to the control system. The algebraic connectivity metric serves as a reliable indicator of process stability, enabling the system to detect and respond to deviations from optimal conditions, thereby significantly improving process reliability and consistency.
3Productivity
If quality inspection is performed after build completion, then measurement simplicity is maintained, but productivity and loss of time worsen due to work in progress being scrapped
Solution Approach 1:
The patent performs quality assessment during the manufacturing process itself rather than after completion. By calculating algebraic connectivity metrics from real-time melt pool images, the system identifies quality issues while they are still developing, enabling corrective action before defective work accumulates. This preliminary detection prevents wasted time and materials on defective builds.
Solution Approach 2:
The patent maintains continuous monitoring and assessment throughout the entire manufacturing process, eliminating idle inspection time at the end. The algebraic connectivity calculation operates continuously on incoming image data, providing uninterrupted quality feedback that allows for real-time process adjustment and ensures consistent workpiece quality without interrupting production flow.
Data Source
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AI summary
A method of controlling an additive manufacturing process in which a directed energy source is used to selectively melt material to form a workpiece, forming a melt pool (52) in the process of melting, the method comprising: using an imaging apparatus to generate an image (72) of the melt pool (52) comprising an array of individual image elements (74), the image (72) including a measurement of at least one physical property for each of the individual image elements (74); from the measurements, mapping a melt pool boundary (76) of the melt pool (52); computing a algebraic connectivity of the melt pool (52); and controlling at least one aspect of the additive manufacturing process with reference to the algebraic connectivity.