Ipg Photonics Corporation

Queen's University at Kingston

Ipg Phontonics

Paul J L Webster

James M Fraser

Victor X D Yang

Jordan Kanko

Christopher M Galbraith

Cole Van Vlack

Genevieve Elizabeth Hayes

Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or 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.

Methods and systems for coherent imaging and feedback control for modification of materials using dynamic optical path switch in the reference arms

A method, apparatus, and system are provided to monitor and characterize the dynamics of a phase change region (PCR) created during laser welding, specifically keyhole welding, and other material modification processes, using low-coherence interferometry. By directing a measurement beam to multiple locations within and overlapping with the PCR, the system, apparatus, and method are used to determine, in real time, spatial and temporal characteristics of the weld such as keyhole depth, length, width, shape and whether the keyhole is unstable, closes or collapses. This information is important in determining the quality and material properties of a completed finished weld. It can also be used with feedback to modify the material modification process in real time.

Methods and systems for characterizing laser machining properties by measuring keyhole dynamics using interferometry

A system and method may be used to monitor and/or control material processing where a process beam is moved in a wobble pattern, such as a wobble-welding process. While at least one process beam is moved according to a wobble pattern on a processing site (e.g., a weld site) of a workpiece, an ICI system moves an imaging beam at least partially independently of the process beam to one or more measurement locations on the wobble pattern and obtains ICI measurements (e.g., depth measurements) at those locations. The ICI measurement(s) may be used, for example, to evaluate keyhole and/or melt pool characteristics during a welding process. Although the present application describes wobble welding processes, the systems and methods described herein may also be used with other material processing applications where a laser or other energy beam is wobbled or dithered during processing including, without limitation, additive manufacturing, marking and material removal.

Systems and methods for monitoring and/or controlling wobble-processing using inline coherent imaging (ICI)

Systems, methods and apparatuses are used for monitoring material processing using imaging signal density calculated for an imaging beam directed to a workpiece or processing region, for example, during inline coherent imaging (ICI). The imaging signal density may be used, for example, to monitor laser and e-beam welding processes such as full or partial penetration welding. In some examples, the imaging signal density is indicative of weld penetration as a result of reflections from a keyhole floor and/or from a subsurface structure beneath the keyhole. The monitoring may include, for example, automated pass/fail or quality assessment of the welding or material processing or parts produced thereby. The imaging signal density may also be used to control the welding or material processing, for example, using imaging signal density data as feedback. The imaging signal density may be used alone or together with other measurements or metrics, such as distance or depth measurements.

Monitoring material processing using imaging signal density determined from inline coherent imaging (ICI)

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.

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Kingston, Canada

Paul J L Webster