JST Optical / Laser Seam Tracker
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Conventional seam tracking systems with tactile probes have been used for many years and have a proven record of success. There are, however, a number of applications where the use of a probe which must "feel" the weld joint can lead to irregular and unreliable results. In these applications, it has been traditional to resort to special probe designs and to have the operator monitor the weld process in order to take corrective action if the seam tracker probe is seen to leave the joint.The introduction of laser tracking permits automatic joint tracking to be used in the more diffi cult joint confi gurations. As the system functions with no contact between the sensor and the joint, there is no tendency for the system to run out of the joint. The system is suitable for all types of joint design and all arc welding purposes. > The compact laser sensor is normally mounted on or near the welding torch. It is of a robust design and construction to function satisfactorily, even in high current and heat environments. Units have been used in applications with welding currents up to 700 amps.The sensor houses laser diodes with optics which project a fan of visible laser light on to the work piece. A CCD camera in the sensor, set at a tri- angulation angle to the laser diodes, receives a refl ection from the surface of the part which is a contour map of the joint geometry. Using triangula- tion permits not only the horizontal features to be detected, but also the height (sensor to work piece distance) to be determined.The sensor is supplied complete with a spatter shield with disposable protective window. This protects the laser diodes and the camera from the heat and fumes of the welding arc. Dry compressed air can be fed to the sensor to assist in cooling and to keep the protective window free of fume buildup. For high heat applications, a water cooled sensor mount is included to integrate with an optional or customer supplied water chiller. > The complete seam tracking system consists of the following elements: Laser Sensor Seam Tracker Control Pendant Control Motorized Cross-SlideAll the elements of the system have been devel-oped to be compatible. There is no need for you to mix and match components from different manu- facturers with all the problems that entails. >

Extractor Module This software stage extracts the seam information and, according to preprogrammed instructions, sets the torch in its correct relative position with the joint, either in the center or a different position.Using this information, the control moves the slides to maintain the correct relative position of the welding torch.The system is capable of working with different joint confi gurations. The seam tracker control is preprogrammed with a number of standard joint geometries. Comparator Module This software section looks at the lines defi ned by the segmentation software and...

Pendant Control > The operator pendant control is supplied as stan-dard with all seam tracking systems and includes the following displays and controls: Two line fl uorescent displayՕ Self-centering jog switches, left-right, up-down Start and stop pushbuttonsՕ Laser on/off pushbutton with warning lamp Seam pushbutton with lamp Օ Error pushbutton with warning lampThe pendant operates in conjunction with the seam tracker control and has different functions according to the setting of the control selector switch. In the RUN mode, the display changes depending on whether the system is in...

The standard unit is suitable for all straightforward tracking operations and will maintain the relative position of the torch to the work piece in both the cross seam and vertical direction.Where the condition of the joint is variable or where, in multi-pass welds, there is a variation of fi ll, alternative systems are available which can measure the joint and calculate the necessary change in travel speed to achieve the necessary fi ll. These systems use the same type of laser sen- sor and work in conjunction with the full range of Jetline fi xturing to ensure that the perfect weld is...