Methods and systems for coherent imaging and feedback control for modification of materials via imaging a feedstock supply stream interferometrically
Inventors
Kanko, Jordan • Webster, Paul • Fraser, James M.
Assignees
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Publication Number
US-11802837-B2
Publication Date
2023-10-31
Expiration Date
Abstract
Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser, sintering, and welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.
Core Innovation
The invention relates to an apparatus and method for additive manufacturing that includes a material processing beam source producing a material processing beam applied to a surface. The additive manufacturing process includes at least one feedstock supply stream, such as a powder feedstock supply stream, and an imaging system that produces at least one imaging beam and includes an optical interferometer configured to produce an interferometry output based on at least one sample optical path length compared to a reference optical path length.
A component of the imaging beam is directed on a sample arm path that intersects the feedstock supply stream, and another component is directed on at least one reference arm path. A processor receives the interferometry output and produces an output used as feedback to control at least one processing parameter of the additive manufacturing process, enabling interface and depth or height related tracking between an opaque-material interface and a feedstock supply stream.
The interferometry-based feedback is used to control processing parameters associated with feedstock and material processing, including powder feedstock and processing-beam parameters. The disclosed approach addresses interferometry data reduction and interface tracking, including handling detector saturation through signal conditioning and dynamic range compression.
The implementation is described as using FPGA/ASIC for low-latency processing and real-time trend tracking algorithms to generate feedback values, and can integrate with auxiliary optical sensors for process monitoring. The disclosed uses include additive manufacturing processing parameter regime assessment and quality assurance, including detecting lack of fusion defects and avoiding false friend defects based on coherent imaging outputs and temperature or process radiation effects.
Claims Coverage
The provided claim set includes two independent claims: one directed to an apparatus and one directed to an additive manufacturing method. Across these independent claims, the inventive features are centered on interferometer-based sample/reference optical path length comparison during additive manufacturing, and generation of feedback used to control processing parameters.
Interferometer-based imaging beam intersects the feedstock supply stream during additive manufacturing
An imaging system produces at least one imaging beam including an optical interferometer that produces an interferometry output based on a sample optical path length compared to a reference optical path length, with the imaging beam directed on a sample arm path that intersects the feedstock supply stream and a component directed on at least one reference arm path.
Processor generates feedback from interferometry output for additive manufacturing parameter control
A processor receives the interferometry output from the imaging system and produces an output used as feedback to control at least one processing parameter of the additive manufacturing process.
Additive manufacturing method uses interferometer interferometry output to produce feedback that controls processing parameters
The method directs a material processing beam to a surface, generates an imaging beam, directs a component of the imaging beam on a sample arm path that intersects the feedstock supply stream, directs a component on at least one reference arm path, uses the optical interferometer to produce interferometry output based on sample optical path length compared to reference optical path length, produces a feedback output based on the interferometry output, and controls at least one processing parameter based on the feedback output.
The independent claims cover an additive manufacturing apparatus and method that combine a material processing beam with an interferometer-based imaging system comparing sample and reference optical path lengths during feedstock-intersecting imaging, and a processor that converts the interferometry output into feedback used to control additive manufacturing processing parameters.
Stated Advantages
Interferometry data reduction and interface tracking, including handling detector saturation through signal conditioning and dynamic range compression.
Low-latency operation through FPGA/ASIC processing and real-time trend tracking algorithms.
Processing parameter regime assessment and quality assurance, including detecting lack of fusion defects and avoiding false friend defects.
Powder feedstock monitoring to support multi-material or composition control, including controlling powder stream velocity/feed rate and the ratio of first-to-second powder feed rates.
Documented Applications
Additive manufacturing process monitoring and control.
Processing parameter regime assessment and quality assurance.
Detection of lack of fusion defects and avoidance of false friend defects.
Powder feedstock monitoring for multi-material or composition control.
Additive manufacturing with feedstock supply streams, including powder feedstock supply streams, using processor feedback based on interferometry output.
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