Abstract: The present invention provides an arc welder in which a robot controller of a teaching playback type robot and a welding power source are of digital control type and the robot controller and the welding power source are coupled through a bus. A welding condition command required for welding and a real welding condition are transmitted digitally through the bus in a parallel mode.

Abstract: An electronics assembly system includes an image acquisition system that is coupled to a controller through an improved interface. The coupling facilitates advanced monitoring and control of the image acquisition system. Multiple image acquisition systems can be coupled to the controller over the same interface.

Abstract: A welding device and a welding method for butt welding two pipes to be welded are provided. The welding device comprises a welding device body, having an electrode unit with a welding electrode and a fixing clamp for holding the pipes to be welded; and electrode position indicating means for indicating a position of the welding electrode with respect to the pipes to be welded. The electrode position indicating means is capable of irradiating an indicating light to the pipes to be welded at the position corresponding to the welding electrode. Therefore, the positions of the butt edge surfaces of the pipes and the welding electrode can be easily and correctly consistent so as to perform a good welding.

Abstract: A method for recognition, determination and localization of at least one arbitrary object or space and the picking up of said object, by at least on robot, in particular, a service robot, which operates independently on the base surface. The method is achieved, whereby the robot is oriented within at least one room by room co-ordinates and/or co-ordinates of arbitrary objects in the room, transmitted to the robot by at least one sensor element, in particular, a transponder or transmitter.

Abstract: An adaptive and synergic fill welding method and apparatus enables automatic, or adaptive fill, and user directed, or synergic fill, modes to provide improved fusion quality, by ensuring that base metal dilution of a weld remains within a predetermined range. The apparatus includes a means for profiling and tracking a joint, and multi-part adjustable welding means. In adaptive fill mode the method automatically varies a plurality of welding parameters in response to measured variations such as joint width between work pieces. In synergic fill mode, the method enables a user to vary multiple welding parameters in response to joint variations by adjusting a single variable, a synergic fill number, which may be controlled by means of a user interface pendent. The multiple welding parameters may include predetermined wire feed speed, torch travel speed, welding voltage and current, torch oscillation width, dwell time, and a plurality of bead size parameters.

Abstract: A robot controller for teaching a robot with high efficiency. The robot controller including command storage unit (21) where a movement command and a work command are stored, command identifying unit (24) for discriminating between the movement and work commands, unit (22) for making/editing a series of work programs or discrete work programs by a combination of the commands, work program storage units (23) where the work programs are stored so as to control the robot according to the stored program, further including a work section identifying unit (25) for identifying a work section of the work program by way of the command identification unit (24) and work section automatic stopping unit (27) for automatically stopping or suspending the execution of the work program at the work section in a standby state when the work section identifying unit (25) identifies the work section during the execution of the work program.

Abstract: Bendings &Dgr;&agr;, &Dgr;&bgr;, and &Dgr;&thgr; are determined by the torques about the axes of coordinate systems disposed to respective joints and by spring constants. Parameters &agr;, &bgr;, and &thgr;0 are determined by adding an amount of twist to corrected D-H parameters &agr;s, &bgr;s, and &thgr;0s when twist is “0”. A rotational angle &thgr;′ (&thgr;st) is determined from a target position x by executing inverse kinematics using the parameters &agr;s, &bgr;s, and &thgr;0s (step S6). Further, a position x′ is determined from the rotational angle &thgr;′ by executing forward kinematics using the parameters &agr;, &bgr;, and &thgr;0, and the difference &Dgr;x between the target position x and the position x′ is determined. The difference is corrected, and a new target position x is set.

Abstract: The invention relates to a short-cycle arc welding system comprising a robot having at least one arm which can be displaced in at least one coordinate axis (x, y, z), a welding head which is positioned on the arm and on which a holding device or holding an element and a lifting device are provided, said lifting device moving the holding device back and forth in relation to the welding head and a measuring system for determining the relative position between a component and an element which is held by the holding device and is to be welded to the component. Said measuring system comprises a foot which is mounted on the welding head and which is embodied in such a way that, during operation, it is in contact with the component in order to determine the relative position between the element and the component.

Abstract: The invention describes a method of positioning a welding torch (10) and a welding wire (13) at the center of a seam (32). The welding torch (10) is positioned by means of a robot arm on a predetermined or programmed position between two seam edges (34, 35), after which an alignment process is run whereby the robot arm moves the welding torch (10) in one direction until a short circuit occurs between the welding torch (10) or the welding wire (13) and a seam edge (34, 35) of the workpiece (16), and the welding torch (10) is then displaced in the opposite direction by the robot arm until another short circuit occurs between the welding torch (10) or the welding wire (13) and another side seam edge (34, 35) of the workpiece (16). A control system (4) then evaluates the displacement path in order to calculate a seam center, on which the welding torch (10) is positioned. No additional hardware components are needed in order to implement the method.

Abstract: Constituent pieces of a structure to be welded are arranged in a desired configuration on a support surface and are welded together at a plurality of weld points to form the welded structure. At least one image of the arrangement of the constituent pieces on the support surface is recorded and the positions of the weld points are determined from the image(s). The welding of the constituent pieces is controlled on the basis of the determined positions of the weld points.

Abstract: An authenticating pattern is disposed on a cover and an authenticating device is disposed in a robot apparatus for authenticating the cover on the basis of the authenticating pattern of the fitted cover. An information holding device for holding inherent information is disposed in the cover and a reading device for reading out the inherent information from the information holding device is disposed in the robot apparatus. A function of detecting an amount of influence due to the cover and changing manifesting patterns of motions as occasion demands on the basis of the detection result is disposed in the robot apparatus.

Abstract: Disclosed herein is a self-diagnosis type welding carriage control system for automatically controlling welding conditions and implementing an oscillation motion. The welding carriage control system includes a main controller for a database, a remote control panel controller, a welding machine and condition controller, motion controllers for oscillation and travel motions, and a digital signal processing controller for managing memories for the respective controllers. The controllers are each provided internally with a central processing unit, and a dual port random access memory so as to share neighboring central processing units and memories through a versa module eurocard bus.

Abstract: In the tracking welder, left and right side wheels are supported rotatably by a pair of bearing units that are pivotally attached on a carriage, and this carriage is provided with a driving source for running the carriage, a transmission system for transmitting a rotational motion of the driving source to the left and right side wheels, a welding torch, a sensor for detecting a route to be welded, a track-controlling motor to be rotate in forward and backward directions in response to a detection signal of the sensor, and a steering system for turning the bearing units in an amount corresponding to a rotational amount of the track-controlling motor. According to this tracking welder, it is possible to automatically perform various kinds of welding including not only fillet welding of a corner between horizontally placed steel plate and web plate erected on the steel plate, but also butt welding of steel plates, for example.

Abstract: The invention describes a welding apparatus (1), which has a current source (2) for supplying electrical power to at least one electrode at a welding torch (10) and a control system (4) cooperating with the current source (2), linked to an input device (22) for entering settings for different welding parameters, several sensing means being provided for detecting various actual values of a welding process. At least one measuring device or system for sensing mechanical motion, in particular a welding wire displacement and/or a welding torch displacement or similar, is provided, which detects a surface structure of an object.

Abstract: A system and method for servoing robot marks using fiducial marks and machine vision provides a machine vision system having a machine vision search tool that is adapted to register a pattern, namely a trained fiducial mark, that is transformed by at least two translational degrees and at least one mon-translational degree of freedom. The fiducial is provided to workpiece carried by an end effector of a robot operating within a work area. When the workpiece enters an area of interest within a field of view of a camera of the machine vision system, the fiducial is recognized by the tool based upon a previously trained and calibrated stored image within the tool. The location of the work-piece is derived by the machine vision system based upon the viewed location of the fiducial. The location of the found fiducial is compared with that of a desired location for the fiducial. The desired location can be based upon a standard or desired position of the workpiece.

Abstract: SEMI-AUTOMATIC WELDER TO CLOSE DISPOSABLE BOXES, consisting of a box-shaped basic part defined by a lower and an upper platform defining an upper assembly and a lower assembly level, the lower level defining means for built-in assembly of a double-welding set, whereas the upper level configures means to assemble a shaping device, above which a ram device is vertically aligned, mounted on a support that has an inverted “L” shape, defined by a horizontal and a vertical branch, the first being crossed by a transmission and driving mechanism protected by plate surrounding devices, and also such transmission and driving mechanism is, on the one side, operatively coupled for vertical and alternated operation of the ram and, on the other side, it is equally coupled to horizontally operate the double-welding set that, in turn, is electrically interconnected with an electrical control panel, mounted on the back of the base.

Abstract: In a welding apparatus and a method thereof for a hermetic compressor, a welding apparatus for a hermetic compressor includes a plurality of three welding torches placed at the circumference of a casing at regular intervals, a driving unit rotating the casing or the welding torches and a control means controlling a current and a voltage applied to the welding torches in accordance with welding conditions and the driving unit. Accordingly the welding apparatus and the method thereof for the hermetic compressor are capable of decreasing sharply a welding time and improving a productivity by installing not less than three welding torches.

Abstract: An arc welding apparatus and control method thereof, changes welding power in real time to achieve favorable welding quality. The welding apparatus includes a robot mechanism such as a welding robot, a welding unit including a welding torch at an articulated portion of the robot mechanism, and a control unit to set a welding profile in accordance with welding conditions and a welding path, and to control the robot mechanism and the welding unit in real time in accordance with the welding profile. The method includes setting a welding condition for a parent metal, setting a welding path on the parent metal, setting a welding profile and change factor in accordance with the welding condition and the welding path, and performing a welding operation in accordance with the welding profile. Therefore, the arc welding apparatus and control method thereof achieves a favorable welding result regardless of a type of parent metal by controlling welding power in real time according to conditions of the parent metal.

Abstract: An electric arc welding robot for welding a zone of a rail or the like comprises a movable, electric arc torch unit for operating the welding, first controlling means for controlling a first displacement of the torch unit substantially in front of the periphery of the zone to be welded, so that welding geometrical locations are read on said zone, by means of reading means connected to a memory unit, for memorizing said welding geometrical locations read on the rail, and second controlling means for automatically controlling a second displacement of the torch unit in front of the zone to be welded, within the limits of said reading and as a function of the welding geometrical locations, as memorized.

Abstract: A probe for touch sensing to determine the position of a workpiece in a robot welding system using a robot driven welding gun for advancing a welding wire in a given direction toward a workpiece. The gun is movable by a robot controlled arm in a selected weld path and the probe comprises a rigid, elongated feeler with a touch tip which feeler is carried by a mechanism fixed with respect to the gun and movable by the mechanism between a retracted position and a known extended position wherein the feeler extends from the mechanism a fixed distance having an outermost contact point for the touch tip where the point has a known spatial relation to the gun. A detector detects when the contact point touches the workpiece to locate the workpiece. Several touches are used to determine the orientation of the workpiece for automatic welding.

Abstract: A robotic system for a robot includes a programmable controller coupled to the robot and a teach pendant coupled to the programmable controller. The teach pendant is adapted to control the robot and includes a processor capable of operating the teach pendant and a display coupled to the processor. The teach pendant also includes a web browser. The web browser is adapted to accept input data in a standard format and display the input data on the display.

Abstract: An arc welding overlay apparatus that comprises a welding head carriage adapted for movement on a track, an index arm mounted for movement in a direction substantially transverse to the track, a slide mounted for movement in a direction substantially transverse to the index arm, a welding torch mounted to the slide, and means for dispensing a filler material to the welding torch. Feedback means and control means cooperate to indicate and control the movement of the weld head carriage, index arm, electric arc length and the filler dispensing rate. Means are also provided for emergency shutdown of the electric power source.

Abstract: A control method for arc welding wherein position control of an electrode or a torch is performed while adjusting welding conditions on the basis of optical information obtained from arc light generated during an arc welding process. Illuminance, which forms the optical information obtained from the arc light, has a certain mutual relationship with the arc length or the torch height, so that the weld control is accomplished based on the illuminance. The control method includes a step of comparing illuminance with reference information based on the mutual relationship, and a step of adjusting the welding conditions on the basis of a result of comparison.

Abstract: When an emergency stop button 12 is pressed after a robot 1 passes a teaching point PN, and then reach a position PE, the robot 1 is stopped at a position PS diverted from the predetermined teaching route L. When the start button is pressed next, the robot 1 moves at a speed VL lower than a teaching speed Vt until it reaches a next first teaching point PN+1. Passing first teaching point PN+1, the robot 1 moves at the teaching speed Vt. The robot 1 moves at the low speed VL at a restarting time, so that an operator can check for interference between the robot 1 and the workpiece W. Passing the next first teaching point PN+1, the robot 1 moves at the teaching speed Vt, so that the reduction of the operation efficiency can be prevented.

Abstract: A method for correcting a preset locus of a teaching point for a welding robot having a touch sensor, includes the steps of positioning a workpiece on a welding jig, performing a touch-sensor tracking for the workpiece relative to reference coordinate axes, calculating a displacement of the workpiece through the touch-sensor tracking, and obtaining a new locus of the teaching point based on a transformation matrix generated on the basis of the displacement. With these steps, the teaching points are correctly updated by a touch sensor tracking without an additional equipment for optional sensor tracking, such as laser sensors and arc sensors.

Abstract: A robot control system and method for controlling a robot that performs working on a working path between a specified working start point and a working end point. The robot control system includes an interrupt request signal generating section for generating a signal for requesting change of the working path of the robot, an upper controller for generating an interrupt signal including a specified changed value for changing in real time the working path of the robot in accordance with the interrupt request signal generating section, and a robot controller for controlling in real time the operation of the robot in accordance with the interrupt signal from the upper controller. Thus, the motion of the robot that is working can be changed in real time.

Abstract: Two pipes are arranged, when forming a deep sea pipeline, end to end thereby defining a circumferentially extending narrow angled (less than 10 degrees) groove. Two arc welding torches are arranged directly adjacent to each other on a single carriage that moves around the pipes, thereby forming a twin arc welding system. The position of the arc of each torch is independently oscillated between the walls of the groove to form a weld therein. The arcs are guided automatically by an electronic guidance system, wherein electrical characteristics (such as arc current voltage and/or impedance) of the welding of each torch with regard to one of the two pipes are compared with the corresponding electrical characteristics relating to the other of the pipes. The position of an arc of a torch may thus be aligned with the center line of the groove.

Abstract: A tracking monitoring device and a tracking control device are provided for determining the state of how a weld line is tracked under arc sensing control to let the oscillating center of a welding torch track a correct weld line along the groove center based on a welding current waveform when the welding torch is oscillated in the direction of the groove width, and for controlling an arc welding process. The tracking monitoring device and the tracking control device can form a weld line less affected by a short-circuit mode or sputtering mode which serves as a disturbance factor in a welding current value and are capable of coping with a welding speed increase in association with higher speed oscillating frequency.

Abstract: A method for forming a cylindrical body utilizing a continuous weld is provided. The method includes feeding a source material including a first edge and a second edge from a coil and offsetting at least one of the first edge and the second edge. The method further includes spiraling the material to form a cylinder, welding the first edge and the second edge together forming a continuous weld, and cutting the cylinder to a selected length. To fabricate a jacket, a longitudinal cut is made in the cylindrical body, at least one cutout is cut, and the continuous weld is an outer fillet weld.

Abstract: A method and system of depositing molten metal from an advancing welding wire to form a root pass of weld metal in the bottom of a gap between first and second metal members having generally flat base elements joined by a metal backing plate extending between said base elements, which method and system includes passing welding current between the welding wire and the metal members from a power supply to create a heat generating welding arc, moving the welding wire in a given direction along selected path over the backing plate, sensing a blow through of the backing plate by the welding arc, reversing said given direction of said welding wire for a short distance when a blow through has been sensed and then, resuming movement of said welding wire in said given direction along the selected path.

Abstract: The invention relates to the field of automated welding, and more particularly, to an automated, gas metal arc welding apparatus for externally welding abutting sections of pipe. The apparatus has a motorized main carriage for travelling circumferentially about one of the pipe sections to be welded. The apparatus is provided with a welding torch which is connected to the main carriage. The welding torch is movable relative to the main carriage by the actuation of a multi-axis drive mechanism. The multi-axis drive mechanism has a horizontal transport mechanism for linearly translating the torch transversely of the weld seam, a vertical transport mechanism for vertically displacing the torch transversely of the weld seam and an angular transport mechanism for pivotally moving the torch transversely of the weld seam. A controller is provided for actuating the various transport mechanisms individually or simultaneously if desired.

Abstract: Constituent pieces of a structure to be welded are arranged in a desired configuration on a support surface and are welded together at a plurality of weld points to form the welded structure. At least one image of the arrangement of the constituent pieces on the support surface is recorded and the positions of the weld points are determined from the image(s). The welding of the constituent pieces is controlled on the basis of the determined positions of the weld points.

Abstract: A gas turbine component can be refurbished and/or repaired with an arc welding process that is used in conjunction with a 6-axis robot, a camera and a robot controller/vision processor. Applied to a wire fed plasma welding process, the vision system identifies the part, constructs a weld path based on the part's individual contour, and calculates a trajectory (with or without sinusoidal oscillation) for the robot arm to follow.

Abstract: Surfaces of a weld seam are measured to determine weld seam characteristics such as weld seam profile, seam shape, misfit in a seam, seam gap, and surface irregularities. A desired weld bead profile is predicted based on the weld seam profile. Optimal welding parameters for the weld process are determined to achieve the desired weld bead profile. As the weld bead is applied along the weld seam, weld bead characteristics are measured to define the actual weld bead profile. The desired weld bead profile is compared to the actual weld bead profile and the weld process is modified if there is a difference between the actual weld bead profile and the desired weld bead profile. Modifications may include changing wire speed, travel speed, torch position, torch angles, or other various welding parameters.

Abstract: The light pinpointing device is for producing a pinpointing light signal at an operative center point of a robot tool. The pinpointing light signal is useful to properly position the robot tool during the teaching phase. The light pinpointing device comprises a frame having first and second opposite ends, the first end being provided with a fastener for fastening the frame to an end of the robot tool. A light source assembly is provided to produce a pair of light beams inside the frame. A lens in front of the light source assembly is provided for directing the light beams through the second end of the frame in converging directions so that the light beams intersect with each other at a distance from the end of the robot tool corresponding to the operative center point thereof, thereby providing the pinpointing light signal.

Abstract: A method provides an exact measurement of the tool center point (TCP) being carried out, preferably in the whole working area of the robot. In this measurement, the robot moves very slowly so that little heat is generated by the driving assemblies and the temperature gradients are as low as possible. The measurement can be made, for example, using a high-precision laser distance and angle measurement system. The measurement is carried out such that a measuring point is moved to working area points and then the deviations of the positions and/or orientations of the measuring point are determined using the laser distance and angle measurement system, i.e. a nominal/actual comparison is made. The TCP can preferably serve as the measuring point. The point must always be selected so that the positioning and orientation deviations of the kinematic chain with respect to the PCT can be determined with sufficient accuracy.

Abstract: Methods for weld monitoring and for laser heat treatment monitoring are provided using infrared emissions. In the method for weld monitoring, an infrared (IR) signature emitted by a hot weld surface during welding is detected. The detected infrared signature is compared with a steady state infrared signature signal. The compared results are correlated with a predetermined weld parameter. The predetermined weld parameter includes at least one of a full penetration weld, a workpiece misalignment, and a workpiece contamination. In the method for monitoring a laser heat treating process, an infrared (IR) energy signal emitted by a workpiece surface during the laser heat treating process is detected. The detected energy signal is compared with a predefined voltage range. The compared results are correlated to identify a potential defect.

Abstract: An off-line teaching apparatus includes an operation command-receiving device for receiving an operation command inputted via an input/output port from a key input device or a coordinate input device and successively storing the operation command in a buffer; an operation command-reading device for successively reading the operation command stored in the buffer; an operation command-counting device for counting a number of operation commands stored in the buffer; and a confirmation sound-generating device for generating confirmation sound upon receipt of the operation command by the operation command-receiving device when a counted value obtained by the operation command-counting device is not less than a predetermined number. Accordingly, the operator is informed, in real time, of the fact that the system responds to the input of the operation command from the operator. Thus, it is possible to improve the operability of the off-line teaching.

Abstract: Parameters of a robot is displayed on a display device of an operation terminal in a manner that parameters having been changed and parameters having not been changed of all the parameters are displayed in a distinguished manner such that the background color of the parameters having been changed differs from that of other data.

Abstract: An operation line searching method in which an operation start position is automatically approached and a robot/sensor system having such function of detecting the operation line. A robot having a laser sensor and an operation tool attached to a distal end thereof approaches an operation start position Q1 using various searching motion path patterns (a) to (d). Pattern (a) is determined to avoid an obstacle F or an obstructively-shaped portion G. The path thereof, for example, can be determined by specifying a coordinate axis of a coordinate system w. Patterns (b) and (c) are carried out by teaching, to the robot, data for determining the paths thereof in order. Pattern (d) is carried out in the following manner: an initial parameter <V1>, an angle of rotation and a norm increase factor are specified as parameters, and at the time when incremental travel quantity of a (i+1)th occurrence (i=0, 1, 2, . . .

Abstract: Apparatus (10) and method of forming a deep sea pipeline or a cross country pipeline by welding pipes together to form the pipeline. Two pipes (2, 4) are arranged so that their ends (26, 27) define a circumferentially extending narrow angled (less than 10 degrees) groove (28). At least two arc welding torches (1) are arranged directly adjacent to each other on a single carriage that moves around the pipes, to form a twin arc welding system. The arcs of the torches (1) form a weld (3) in the groove. The carriage is moved around the pipe, the torches thus moving around the pipe with the same speed. Each torch (1) is independently oscillated so that the position of its arc oscillates between the walls of the groove.

Abstract: A method and system for automatically filing the narrow gap between facing end walls of adjacent first and second railway rails by depositing vertically spaced layers of molten metal in the gap with an electric arc welding torch using a robotic mechanism that moves the torch in a pattern controlled by a low level robotic execute program from a spatial position to a next spatial position, said method and system comprising: constructing a data array for a specific gap, said array constituting a series of positions making up an idealized progression of said torch to fill said gaps in vertically spaced layers made up of multiple positions, each of said fixed positions identified by at least four coordinates, including (1) at least x, y and z, (2) the layer in which said position is a part and (3) the welding parameters to be executed while said torch moves toward the next position; outputting data relating to a specific position from said data array; processing said welding parameters associated with said outputt

Abstract: Disclosed is a method for correcting teaching points for a welding robot. The method for correcting teaching points for a welding robot having a touch sensor, comprising the steps of mounting a workpiece to a welding jig; establishing at least one teaching point between an initial welding point and a terminating welding point; touch-sensing the workpiece at a point corresponding to the established teaching point through the touch sensor; identifying a point detected by the touch-sensing; and obtaining a new teaching point based on the difference between the established teaching point and the detection point. With these steps, the teaching points are correctly updated by a touch sensor tracking without an additional equipment for optional sensor tracking, such as laser sensors, arc sensors, etc., thereby performing the welding operation along the correct welding path.

Abstract: A method of monitoring the alignment of pipes to be welded end to end involves supporting a reference bar extending generally parallel to, and external of, the pipes so as to span a weld position of which the ends of two pipes are to be welded, performing measurements of perpendicular distance between the bar and each pipe at two predetermined distances from the end of each pipe, determining the thickness of the walls of the pipes, determining the slope of the exterior of each pipe with respect to the reference bar, calculating from the slopes the difference between the distances from the bar to the outer surface of each of the two pipes to the weld position, so as to provide a measure of the misalignment of the outer surface of the pipes at the weld position, differencing the wall thicknesses of the pipes to provide a wall thickness difference, and subtracting the wall thickness difference from the misalignment of the external walls of the pipe to determine the misalignment of the inner surfaces of the pipes

Abstract: An electric arc welding apparatus for depositing molten metal from an advancing welding wire into a weld puddle in an open root between two juxtapositioned plates where the root extends in a welding path and is formed by converging walls terminating in generally parallel walls spaced to define a gap, which apparatus comprises a contact holder with a wire outlet, a switching power supply directing welding current to the wire as the wire passes from the outlet toward the open root, with the advancing wire defining an electrode stick out between the contact holder and the weld puddle, a circuit for sensing the length of the stick out, and control means for adjusting the welding current as a function of the sensed stick out length.

Abstract: A method of determining position information of a workpiece relative to a robot includes the ability to move the workpiece into a variety of orientations relative to the robot during the touch sensing location procedure. The position information is then used for performing a robot operation including coordinated motion. A coordinated reference frame is defined with respect to a moveable positioner that supports the workpiece. Known kinematic relationships between the positioner and the robot are used to control operation of the robot within the coordinated reference frame throughout the touch sensing location procedure. By moving the workpiece relative to the robot during the touch sensing location procedure, a greater variety of workpieces can be processed and relatively complicated workpiece configurations can be accurately determined. The robot operating parameters are modified according to the determined position information.

Abstract: A method and system of depositing molten metal from an advancing welding wire to form a root pass of weld metal in the bottom of a gap between first and second metal members having generally flat base elements joined by a metal backing plate extending between said base elements, which method and system includes passing welding current between the welding wire and the metal members from a power supply to create a heat generating welding arc, moving the welding wire in a given direction along selected path over the backing plate, sensing a blow through of the backing plate by the welding arc, reversing said given direction of said welding wire for a short distance when a blow through has been sensed and then, resuming movement of said welding wire in said given direction along the selected path.

Abstract: Both a method and apparatus for regulating the position of a camera in a thermographic control and monitoring arrangement is provided for a system for welding together at least two metal plates along a joint plane. The apparatus includes a welding head that generates a high energy-density welding beam, a camera for thermographically monitoring the welding carried out by the welding beam, a movable frame member for supporting the welding head and camera, a fixed light source disposed in a zone that is accessible by the welding beam generated by the welding head, and an adjustment assembly for regulating the position of the camera with respect to the welding head. In the method, the welding beam is moved into a reference position with respect to a point source of light. Next, the frame member is displaced by a specific distance d corresponding to the distance desired between an impact point I of the welding beam and the field of view of the camera on the plate is being welded.