US 12,257,644 B2
Methods and systems for characterizing laser machining properties by measuring keyhole dynamics using interferometry
Paul J. L. Webster, Kingston (CA)
Assigned to IPG Photonics Corporation, Oxford, MA (US)
Filed by IPG Photonics Corporation, Oxford, MA (US)
Filed on Aug. 29, 2022, as Appl. No. 17/897,905.
Application 17/897,905 is a continuation of application No. 16/858,032, filed on Apr. 24, 2020, granted, now 11,426,816.
Application 16/858,032 is a continuation of application No. 16/383,544, filed on Apr. 12, 2019, granted, now 10,654,126, issued on May 19, 2020.
Application 16/383,544 is a continuation of application No. 15/684,145, filed on Aug. 23, 2017, granted, now 10,413,995, issued on Sep. 17, 2019.
Application 15/684,145 is a continuation of application No. 14/775,136, granted, now 9,757,817, issued on Sep. 12, 2017, previously published as PCT/CA2014/000273, filed on Mar. 13, 2014.
Claims priority of provisional application 61/778,592, filed on Mar. 13, 2013.
Prior Publication US 2023/0036545 A1, Feb. 2, 2023
Int. Cl. B23K 26/03 (2006.01); B23K 9/00 (2006.01); B23K 10/02 (2006.01); B23K 15/00 (2006.01); B23K 26/06 (2014.01); B23K 26/082 (2014.01); B23K 26/14 (2014.01); B23K 26/244 (2014.01); B23K 31/12 (2006.01); G01B 5/00 (2006.01); G01B 9/0209 (2022.01); G01B 11/22 (2006.01); G01B 11/24 (2006.01); G01N 21/954 (2006.01); G01S 7/481 (2006.01); G01S 17/89 (2020.01); B26F 1/26 (2006.01); B26F 3/00 (2006.01)
CPC B23K 26/032 (2013.01) [B23K 9/00 (2013.01); B23K 10/02 (2013.01); B23K 15/0046 (2013.01); B23K 26/0643 (2013.01); B23K 26/0648 (2013.01); B23K 26/082 (2015.10); B23K 26/14 (2013.01); B23K 26/244 (2015.10); B23K 31/125 (2013.01); G01B 5/0037 (2013.01); G01B 9/0209 (2013.01); G01B 11/22 (2013.01); G01B 11/2441 (2013.01); G01N 21/954 (2013.01); G01S 7/4817 (2013.01); G01S 17/89 (2013.01); B26F 1/26 (2013.01); B26F 3/004 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A system comprising:
a material processing laser source configured to generate a material processing beam that is applied to a sample location in a material modification process and creates a phase change region (PCR) in a material of the sample, wherein the material modification process includes a keyhole welding process and the PCR includes a keyhole;
an imaging system configured to produce an imaging beam;
an interferometer having a reference arm configured such that a first component of the imaging beam applied to an input of the reference arm results in an output signal of the reference arm, a sample arm configured such that a second component of the imaging beam applied to the sample arm results in an output signal of the sample arm, at least a component of the output signal of the sample arm including reflections of the component of the imaging beam from the sample location, a combiner configured to combine the output signal of the reference arm and the output signal of the sample arm to produce a combined signal as an interferometry output, and
a signal detector configured to produce an interferogram from the interferometry output;
a deflection element configured to control a direction of the imaging beam; and
a controller coupled to the deflection element and configured to control the deflection element such that
alignment of the imaging beam relative to a feature of the PCR is maintained, wherein the feature of the PCR is substantially a bottom surface of the keyhole of the PCR, and
a center of the imaging beam is directed to lag behind the material processing beam in a direction that is related to a velocity direction of the material processing beam relative to the sample location.