公开(公告)号：US06555780B1

公开(公告)日：2003-04-29

申请号：US10006140

申请日：2001-12-10

申请人： Cheol-Jung Kim ,  Sung-Hoon Baik ,  Min-Suk Kim ,  Chin-Man Chung

发明人： Cheol-Jung Kim ,  Sung-Hoon Baik ,  Min-Suk Kim ,  Chin-Man Chung

IPC分类号： B23K2620

CPC分类号： B23K26/032 ,  B23K26/03 ,  B23K26/034

摘要： In a laser welding, a laser beam is focused on a workpiece by a focusing lens or lenses. The focusing lens or lenses image an aperture liming the size of the laser beam on the workpiece and the size of focused laser beam is the image size of the aperture on the workpiece at the wavelength of the laser. A weld pool is generated by the interaction of the focused laser beam and the workpiece. Due to the thermal conduction of the workpiece, the size of the weld pool is generally not the same as the size of the focused laser beam and varies with the power of the laser or with the focus shift of the focusing lens or lenses. The weld pool irradiates a thermal radiation. The thermal radiation is measured back through the focusing lens or lenses and through the aperture limiting the size of the laser beam or any other aperture limiting a size of the thermal radiation to be measured in three spectral bands with single element detectors. Due to the chromatic aberration of the focusing lens or lenses, the transmittance of each spectral band of the thermal radiation varies with the size variation and with the focus position of a weld pool and the spectral band signals measured with single-element detectors vary if the size and/or the focus position of a weld pool varies. However, the chromatic aberration of the focusing lens or lenses is usually unknown and is not easy to measure. A method to monitor the size variation and/or the focus position of a weld pool is disclosed wherein the effects of the chromatic aberration are measured experimentally and the size variation of a weld pool is monitored independently from the focus shift of the focusing lens or lenses and the focus position of a weld pool is monitored independently from the power variation of the laser.

摘要翻译： 在激光焊接中，激光束通过聚焦透镜聚焦在工件上。 聚焦透镜或透镜对激光束在工件上的尺寸进行成像，并且聚焦激光束的尺寸是在激光波长处工件上的孔径的图像尺寸。 焊池由聚焦激光束与工件的相互作用产生。 由于工件的热传导，熔池的尺寸通常与聚焦的激光束的尺寸不同，并随着激光的功率或聚焦透镜的聚焦偏移而变化。 焊接池照射热辐射。 通过聚焦透镜或透镜测量热辐射，并通过孔径限制激光束或任何其他孔径的尺寸，以单个元件检测器限制三个光谱带中待测量的热辐射的尺寸。 由于聚焦透镜或透镜的色差，热辐射的每个光谱带的透射率随着尺寸变化和焊池的焦点位置而变化，并且用单元件检测器测量的光谱带信号变化如果 焊池的尺寸和/或焦点位置不同。 然而，聚焦透镜或透镜的色差通常是未知的并且不容易测量。 公开了一种用于监测焊池的尺寸变化和/或焦点位置的方法，其中色差的影响通过实验测量，并且独立于聚焦透镜或聚焦透镜的聚焦偏移监测焊池的尺寸变化 并且独立于激光器的功率变化监测焊池的聚焦位置。

公开(公告)号：US06344625B1

公开(公告)日：2002-02-05

申请号：US09589134

申请日：2000-06-08

申请人： Cheol-Jung Kim ,  Sung-Hoon Baik ,  Min-Suk Kim ,  Chin-Man Chung

发明人： Cheol-Jung Kim ,  Sung-Hoon Baik ,  Min-Suk Kim ,  Chin-Man Chung

IPC分类号： B23K2620

CPC分类号： B23K26/032 ,  B23K26/034 ,  B23K26/04

摘要： In a laser welding, a laser beam is focused on a workpiece by a focusing lens or lenses. The focusing lens or lenses image an aperture liming the size of the laser beam on the workpiece and the size of focused laser beam is the image size of the aperture on the workpiece at the wavelength of the laser. A weld pool is generated by the interaction of the focused laser beam and the workpiece. Due to the thermal conduction of the workpiece, the size of the weld pool is generally not the same as the size of the focused laser beam and varies with the power of the laser or with the focus shift of the focusing lens or lenses. The weld pool radiates a thermal radiation. An apparatus and method is disclosed wherein the thermal radiation is measured back through the focusing lens or lenses and through the aperture limiting the size of the laser beam or any other aperture limiting a size of the thermal radiation to be measured in at least three spectral bands with single element detectors. Due to the chromatic aberration of the focusing lens or lenses, the transmittance of each spectral band of the thermal radiation varies with the size variation and with the focus position of a weld pool and the spectral band signals measured with single-element detectors vary if the size and/or the focus position of a weld pool varies. Algorithm to monitor the size variation and/or the focus position of a weld pool is disclosed wherein the size variation of a weld pool is monitored independently from the focus shift of the focusing lens or lenses and the focus position of a weld pool is monitored independently from the power variation of the laser.

摘要翻译： 在激光焊接中，激光束通过聚焦透镜聚焦在工件上。 聚焦透镜或透镜对激光束在工件上的尺寸进行成像，并且聚焦激光束的尺寸是在激光波长处工件上的孔径的图像尺寸。 焊池由聚焦激光束与工件的相互作用产生。 由于工件的热传导，熔池的尺寸通常与聚焦的激光束的尺寸不同，并随着激光的功率或聚焦透镜的聚焦偏移而变化。 焊接池辐射热辐射。 公开了一种装置和方法，其中通过聚焦透镜或透镜测量热辐射，并通过孔径限制激光束或任何其它孔径的尺寸，以限制在至少三个光谱带中待测量的热辐射的尺寸 与单元素检测器。 由于聚焦透镜或透镜的色差，热辐射的每个光谱带的透射率随着尺寸变化和焊池的焦点位置而变化，并且用单元件检测器测量的光谱带信号变化如果 焊池的尺寸和/或焦点位置不同。 公开了监测焊池的尺寸变化和/或焦点位置的算法，其中独立于聚焦透镜或透镜的聚焦位移监测焊池的尺寸变化，并且独立地监测焊池的聚焦位置 从激光的功率变化。

公开(公告)号：US06188041B1

公开(公告)日：2001-02-13

申请号：US09190234

申请日：1998-11-13

申请人： Cheol-Jung Kim ,  Min-Suk Kim ,  Sung-Hoon Baik ,  Chin-Man Chung

发明人： Cheol-Jung Kim ,  Min-Suk Kim ,  Sung-Hoon Baik ,  Chin-Man Chung

IPC分类号： B23K2600

CPC分类号： B23K26/034 ,  B23K26/04 ,  B23K26/0643 ,  B23K26/0665

摘要： A method and apparatus for real-time weld process monitoring are provided for a pulsed laser welding. The thermal radiation from a weld pool is measured at several spectral bands through an aperture with single-element detectors after splitting the spectral bands with dichromatic mirrors and beam splitters. The distal end of an optical fiber for laser delivery can be used as an aperture and each spectral band signal is measured with a single-element detector. Due to the chromatic aberration of an imaging optics, the field of view from a single-element detector through the aperture is varied by the wavelength of spectral band. The weld pool size contributing to the spectral band signal varies by the wavelength of the spectral band. The transmittance profile of each spectral band also depends on the focus shift of imaging optics. By processing the measured spectral band signals, the size of a weld pool, the power variation on a workpiece and the focus shift of imaging optics can be monitored simultaneously. Furthermore, the weld pool sizes at predetermined positions in time are correlated to the weld depth and the weld defect such as a weld gap for weld quality assurance.

摘要翻译： 为脉冲激光焊接提供了实时焊接过程监控的方法和装置。 在使用双色镜和分束器分割光谱带之后，通过具有单元件检测器的孔径在几个光谱带处测量来自熔池的热辐射。 用于激光输送的光纤的远端可以用作孔径，并且每个光谱带信号都用单元件检测器测量。 由于成像光学元件的色差，来自单元件检测器通过孔径的视场由光谱带的波长变化。 有助于光谱带信号的焊池尺寸随光谱带的波长而变化。 每个光谱带的透射率分布也取决于成像光学元件的聚焦偏移。 通过处理测量的光谱带信号，可以同时监测焊池的尺寸，工件上的功率变化和成像光学器件的聚焦偏移。 此外，预定位置的焊池尺寸与焊接深度和焊接缺陷（例如用于焊接质量保证的焊接间隙）相关。