Determination of weld quality in pulsed Nd:YAG laser welds using IR and acoustic sensors

Bates, Gregory; Kelkar, Girish

doi:10.2351/1.5065769

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…There are a number of methods to implement each of the laser welding functionalities with the use of different types of sensors (tactile, ultrasonic, electromagnetic, etc) [1,2]. Still only few of them can be equally efficient when used for each of the three required sensor functionalities (detection, inspection, process control).…”

Section: Sensing Methods Overviewmentioning

confidence: 99%

Sensor integration for robotic laser welding processes

Iakovou¹,

Aarts²,

Meijer³

2005

International Congress on Applications of Lasers &Amp; Electro-Optics

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The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process, a separate sensory system is required. The use of separate sensory systems leads to heavy and bulky tools, in contrast to compact and light sensory systems that are needed to reach sufficient accuracy and accessibility. In the solution presented in this paper all three subprocesses are integrated in one compact multipurpose welding head. This multipurpose tool is under development and consists of a laser welding head, with integrated sensors for seam detection and inspection, while also carrying interfaces for process control. It can provide the relative position of the tool and the work piece in three-dimensional space. Additionally, it can cope with the occurrence of sharp corners along a three-dimensional weld path, which are difficult to detect and weld with conventional equipment due to measurement errors and robot dynamics. In this paper the process of seam detection will be mainly elaborated.

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Section: Sensing Methods Overviewmentioning

confidence: 99%

Sensor integration for robotic laser welding processes

Iakovou¹,

Aarts²,

Meijer³

2005

International Congress on Applications of Lasers &Amp; Electro-Optics

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“…Several types of sensor have been developed to monitor the welding process, among which the photodiode sensor (PS) has been extensively used for process sensing and control [5][6][7][8][9][10][11][12]. Some researchers have also demonstrated the optimization and closed-loop control of focal point position [13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Double closed-loop control of the focal point position in laser beam welding

Zhang

Chen

Jiang

et al. 2003

Meas. Sci. Technol.

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Focal point position control is significant in deep penetration laser beam welding because it is apt to change during welding due to some fluctuating factors, such as the non-planar workpiece, welding distortion and thermal focusing. This work describes the design of a double closed-loop control of the focal point position for CO2 laser beam welding. A photodiode sensor (PS) and a plasma charge sensor (PCS) are simultaneously utilized to detect the optical emission and plasma charge current in welding. It is found that the PCS signal could be used to control the nozzle–workpiece distance based on the decrease of PCS signal intensity with increasing nozzle–workpiece distance. The PS signal could be used to control the focal point position by using PS signal variation with focal point position. Therefore, a system for double closed-loop controlling the focal point position has been set up, using the PCS signal to control the nozzle–workpiece distance and the PS signal to control the focal point position. The experimental results with a non-planar workpiece show that the double closed-loop control of the focal point position not only automatically follows the contours of the workpiece surface, but also controls the focal point position constant by compensating the effect of thermal focusing.

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