Laser Pixel Array Optics for Stable High-Rate Metal AM
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Solution Overview
Problem
Current selective laser melting processes in metal additive manufacturing are limited by the ability to deliver energy to the build surface in a controlled manner, leading to issues such as metal vaporization, melt pool instability, and reduced processing rates while maintaining part resolution and accuracy.
Innovation Solution
The use of a linear array of laser energy pixels with rectangular shapes and uniform power density, arranged without spacing, allows for controlled energy delivery to the build surface. This configuration enables scanning of the energy line primarily perpendicular to its long axis, maintaining high part resolution and accuracy while potentially increasing processing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser spot is scanned over a thin layer of metal powder in selective laser melting, then metal powder is melted and fused into a solid metal structure, but the effective rate of the process is limited by the ability to deliver energy into the build surface in a controlled manner
Solution Approach 1:
The laser beam is divided into multiple discrete spots arranged in a grid pattern, allowing simultaneous processing of multiple locations on the build surface. This segmentation enables parallel energy delivery while maintaining precise control over each individual spot's energy placement, thereby increasing effective rate without sacrificing manufacturing precision
Solution Approach 2:
Multiple laser spots are combined into a coordinated array that operates simultaneously on different regions of the metal powder layer. By merging the functionality of multiple laser sources or time-multiplexed spots into a unified processing system, the effective rate increases while the control system maintains precision for each spot's energy delivery
2Productivity
If laser power is increased to increase processing rates, then more material can be processed per unit time, but metal vaporization and melt pool instability occur
Solution Approach 1:
The total laser power is distributed across multiple discrete spots rather than concentrated in a single high-power beam. This segmentation allows the system to process more material per unit time through parallel spots while each individual spot maintains lower power levels that prevent vaporization and maintain melt pool stability
Solution Approach 2:
Each laser spot in the array can be independently controlled with specific power levels optimized for local conditions. This local quality control ensures that each spot delivers just enough energy to melt and fuse the metal powder without exceeding the threshold that causes vaporization, maintaining reliability while achieving high overall processing rates
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 approach allows for an arbitrarily large amount of laser power to be delivered to the build surface in a controlled profile, enhancing processing rates while maintaining part resolution and accuracy, even over larger build volumes.
Implementation Method 1
Each optical fiber is configured to transmit laser energy from a first end coupled to an associated laser energy source of the two or more laser energy sources and out of a second end
Implementation Method 2
an optics assembly constructed and arranged to shape the laser energy output from each optical fiber to form a rectangular laser energy pixel associated with each laser energy source
Implementation Method 3
exposure of a layer of material on the build surface to the linear array of laser energy pixels melts at least a portion of the layer of material
Data Source
AI summary
Aspects described herein relate to additive manufacturing systems and related methods. An additive manufacturing system may include two or more laser energy sources and associated optical fibers. An optics assembly may be constructed and arranged to form a rectangular laser energy pixel associated with each laser energy source. Each pixel may have a substantially uniform power density, and the pixels may be arranged to form a linear array of laser energy pixels on a build surface with no spacing between the pixels. Exposure of a portion of a layer of material on the build surface to the linear array of laser energy pixels may melt the portion of the layer.