Video data generated at a high rate by a camera observing a welding operation is selectively stored in a video-computer interface to permit later computer analysis of the data. Special multiple memory techniques can be employed when the rate of which the data is generated is too fast for storage in a single memory in the interface. The width of the weld pool is detected by finding local minima of light intensity associated with these edges. The mass of the weld pool and the weld penetration can be measured and controlled by causing oscillations in the weld pool and measuring the natural frequency of such oscillations. The weld line can be tracked either by bouncing a beam of light off the welding electrode so as to form an illuminated area and detecting the resulting irregularity where the illuminated area crosses the weld line, or by detecting the deformation in the surface of the weld pool as the pool flows into the gap between the metal portions being joined. Prior to welding, the weld line can be detected by establishing a low power welding arc insufficient to create a molten weld pool but generating enough light to produce an irregularity in the reflected light at the location of the weld line.

Apparatus and methods for controlling a welding process

A mobile automated pipeline welding and quality control system comprising a gas metal arc welding carriage and a weld data monitor and acquisition unit The welding carriage carries a welding torch, wire feed device for feeding consumable wire to the torch, an oscillator for oscillating the torch and a motorized drive mechanism for moving the carriage about a weldment A controller for the carriage includes digital control circuitry for dosed loop control of the drive, oscillator and wire feed devices By default, the controller operates each device at one of a plurality of pre-programmed nominal speeds selected from a mode table The controller is responsive to drive, oscillation and wire feed speed variation signals under the control of an operator, and varies the speed of each device within speed ranges which are selected to ensure compliance with welding specifications The monitor has voltage and current transducers for measuring current and voltage at the welding torch The controller supplies the monitor with speed data relating to the drive, oscillator and wire feed devices All of this information can be displayed and recorded in the monitors memory In addition, the monitor can compute and display the heat input into the weld based on the detected welding parameters This information allows the operator to make minute adjustments during the welding process to ensure that a weld falls within specifications

Mobile automated pipeline welding and quality control system

The invention relates to an orbital welding device for mobile use in order to join a first pipe end (1) and a second pipe end (2) along a circumferential joint (3) by means of at least one weld seam (4), particularly for producing a pipeline (5) to be placed on land. The inventive device comprises a guide ring (6), which can be oriented toward the first pipe end (1) and the circumferential joint (3), and an orbital carriage (7) that can be motor-displaced along the guide ring (6) via an advancing device (8). On the orbital carriage (7), a laser welding head (12) for directing a laser beam (10) into a laser welding zone (13) is mounted in a manner that enables it to be oriented toward the circumferential joint (3) whereby enabling the production of the weld seam (4) along the circumferential joint (3) by displacing the orbital carriage (7). The laser beam (10) is produced by a high-power fiber laser beam source (9) located, in particular, on a mobile transport vehicle (35) while being situated at a distance from the orbital carriage (7), is guided by light guide (11) passing though a tube bundle (50) to the orbital carriage (7) and then supplied to the welding head (12). A significant advantage of the invention resides in the fact that the joining of two pipe ends by means of only one single welding process during a short period of time is made possible in the field with autonomous operation.

Orbital welding device for pipeline construction

An electric welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply (SMPS) as control element, the switching mode power supply preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed to a microprocessor via an entry keyboard, and in the microprocessor they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modulator of the switching mode power supply. The pulse width modulator is connected to the driver stages of the switching stages of the switching mode power supply, which switching stages are designed as boost regulator of buck regulator, and thus a pulse width modulation of the current pulses of the switching stages is effected in dependence on the difference between actual and nominal value. The converter section of the switching mode power supply preferably is designed as a modified single-ended buck regulator or as a push-pull full bridge, wherein it is operated at a fixed clock frequency of about 25 kHz. The secondary coil of the transformer of the switching mode power supply being either direct in connection with the output connection terminals of the switching mode power supply, or a secondary rectifier is connected between the secondary coil and the output connection terminals, whereby the secondary rectifier can be bridged by switch means.

Electronic welding apparatus

A system (and method) of controlling and simultaneously displaying arc welding torch parameters includes a power supply for supplying weld voltage and current to the torch in accordance with demand signals from a computer. The computer also supplies a demand motor speed to a motor for controlling the travel speed of the torch electrode relative to a workpiece or the fed rate of a filler wire to the weld area. The actual values of the weld voltage/current and the motor speed are fed back to the computer and displayed on a video color display in separate colors and in real time to enable on operator to readily correlate the actual with the demand parameter values. The position of the electrode relative to the workpiece is also fed back to the computer for presentation on the video display. In addition, deviations of the individual actual parameter values from acceptable tolerance limits are highlighted on the display.

Method and apparatus for controlling and simultaneously displaying arc welding process parameters

Method for controlling an automatic pipe welder is disclosed. In the automatic welder which requires remote control, welding conditions for butt welding pipes are stored and an actual joint geometry or groove shape is sensed. From signals relating to the stored welding conditions and the sensed groove shape, a control command signal in actual welding is produced to effect welding under an optimum condition. On the other hand, an arc condition at an actual welding point and a melting condition of a metal are monitored and displayed to modify the welding conditions in accordance with the monitored condition to control the automatic pipe welder.

Method for controlling an automatic pipe welder

Disclosed is a control apparatus for an automatic pipe welder, for controlling the automatic pipe welder which continuously butt welds pipes while it is running along a welding line on the periphery of a pipe, in accordance with predetermined welding conditions for each of a plurality of welding areas sectioned along the welding line. All of the welding conditions for the welding areas are stored in a digital storage device while welding conditions on an area currently being welded are stored in another storage device. The contents of the second-mentioned digital storage device are converted by a digital-analog converter to analog signals, which are then held respectively in corresponding sample and hold circuits. Outputs of the sample and hold circuits are supplied as control commands to respective control units which control the welder in accordance with the welding conditions. In this manner, the construction of the control apparatus and a control panel thereof is simplified.

Keiziro Sakai

Papers

Method for controlling an automatic pipe welder

Control apparatus for an automatic pipe welder

Steuereinrichtung fuer automatisches rohrschweisswerk