DE29822666U1 - Automatic arc welding machine with universal seam tracking for shipbuilding and steel construction - Google Patents

Description

The welding of section or module joints in shipbuilding is mainly done manually under assembly conditions. Since the parts to be joined cannot be clamped in processing machines, the shipbuilders have to go to the component with the process (welding device). The processes used are MIG/MAG and ε-hand. Every joint to be welded must be accessible along its entire length, so that racks must be set up on vertical and diagonal joints, the levels of which give the welder a secure hold. Due to changes in position and posture, moving along the joint always leads to an interrupted seam. When using stick electrodes, many additional starting points arise due to the electrode change. The physically very strenuous and monotonous activity of welding therefore leads to seam defects that have to be eliminated at great expense and in a time-consuming manner.

In recent years, welding tractors with the UP and MIG/MAG processes have been increasingly used for assembly welding in pre- and final assembly due to the length of the individual seams. These tractors guide the welding gun along a rail over the weld joint. One or two welders are required to operate these devices, who must take on the assembly and exact alignment of the rails at the joint and constantly monitor the process in order to manually compensate for the deviations between the rail and the joint using mechanical adjustment devices. Due to physical fatigue, constant position changes and necessary auxiliary work for seam preparation and follow-up, a very good manual welder achieves 25...35% during a shift.

Arc burning time. A disadvantage of using currently available mechanical rail-guided systems is the complex, precise laying of the rails parallel to the joint. Furthermore, the operator must be present at all times during the welding process. The welder practically continues to produce the seam by hand, only using an expensive additional device. The economic efficiency of the use is only based on improved seam quality. With a mechanized tractor system, an arc burning time of over 50% can be achieved.

The invention specified in claim 1 is based on the problem of creating an automatic welding machine that, after positioning and setting at the beginning of the seam, automatically follows the weld joint and welds it to the required quality. Changes in the position of the seam in relation to the tractor rail should be automatically recorded, saved and the welding torch adjusted accordingly so that the welding process runs largely without monitoring and the effort involved in installing the rails is minimized. The sensor systems must be robust in accordance with the harsh environmental conditions during welding. The automatic machine should be able to be adapted to any welding machine with a flat current-voltage characteristic curve. When used, the duty cycle (arc burning time) should be increased compared to mechanical systems. Furthermore, the operator should be freed up to carry out other tasks during the welding process, including operating multiple machines.

The core of the automation solution is an arc sensor. This provides information about the joint to the control system. For one-dimensional distance measurement, the arc sensor uses the electrical process parameters, which are changed by intentionally influencing the arc length. If the arc is swung across a joint with a V-seam cross-section, the arc length and thus the welding current changes on the slanted joint flanks. With rapid deflection, a strong current rise is obtained for a short time. This makes it possible to establish the connection between the joint geometry and the swinging movement. The welding machine has a microcontroller as hardware. Combined with an intelligent control and sensor concept, this is housed directly on the vehicle and thus replaces the external computer that is common in other sensor systems.

The control saves the exact location of the first welded layer of the seam, i.e. the waypoints of the travel path are stored values to which specific data of the joint are assigned. For torch guidance when welding the following layers, the specific seam position, including the path data of interrupted seams, can be called up, thus eliminating the need for further sensing. A smoothing algorithm for the path data * straightens the subsequent welds and produces very smooth cover layers. ; ■

The welding machine type can be freely selected and is controlled via the standardized « interface of the remote control. The operator reacts to changing gap widths by adjusting the pendulum width and welding speed. If the joint preparation is carried out using mechanical means as part of precision production, this is very constant over long lengths. Corrective intervention is then only necessary at longer intervals. When welding intermediate and cover layers, the process can be set so stably that the operator does not need to observe it. This means that occasional intervention by the operator is only required in the root layer. The welding machine can be used flexibly and can weld seams in the PA (trough layer), PC (crosswise), PE (overhead) and PF (vertical) positions both in closed halls and outdoors. The time-consuming, precise laying of the guide rails is no longer necessary, as the additional axes automatically compensate for the distance to the seam.

An advantageous embodiment of the invention is specified in claims 2 and 3.

The compact design makes the device easy to handle.

All settings on the welding machine and the welding station are made using a clearly laid out control panel. The device can be controlled both locally and remotely. Several data sets of the welding and oscillation parameters can be programmed and specified.

The inclination around the arc base point is realized by a parallelogram linkage.

The torch can be tilted positively and negatively in the direction of travel (welding feed) of the device. The inclination of the torch towards and away from the device can be adjusted across the direction of travel.

An embodiment is explained using Figures 1 to 3. They show:

Fig. 1 the machine in the front view

Fig. 2 the machine in side view

Fig. 3 the linear units and the tilting mechanism for the burner adjustment

The figures show a compact device with integrated sensor-guided control, ;· · · ·« that can be mounted on various guide rail systems 1 and is operated using a *... clear control panel 2. A feed tractor 3 is integrated for ";* guiding the welding torch 4 along the welding joint 5. The housing with the control *··* 6 is mounted on the mounting plate of the carriage. The deviations between the rail . .··,

··♦■· and joint are compensated by a 2-axis, electrically driven cross support made of . .··, linear units 7, which is mounted at the front end of the carriage. It consists of two linear modules arranged crosswise. The slide guides are completely encapsulated. The distance axis can be adjusted in height, the cross axis is attached centrally to the distance axis. The axes are driven by the flanged DC servo motors 8 via planetary and toothed belt gears. The arrangement of the axes keeps the moving masses small. The slide of the cross axis carries the boom 9 with the tilting mechanism 10 for the burner. On the axis support there is a quick-release strain relief 11 with the current sensor (HALL converter) 12. All parameter settings are made on the control panel 2, which is connected to the control system by a cable. The control cables to the welding power source 14, to the feed tractor 3 and to the DC servo motors 8 originate from the control system. A tactile height sensor 13 is mounted on the transverse axis, which also makes it possible to compensate for height changes (sheet metal curvatures) that cannot be detected by the arc sensor and prevents the torch from hitting deck joints.

The instantaneous welding current is tapped, galvanically isolated, by an external current sensor (HALL converter) 12 pushed onto the hose package.

List of reference symbols

1 guide rail system

2 Control panel

3 Feed tractor

4 welding torches

5 Weld joint

6 Housing with control

7 linear units

8 DC servo motors

9 booms

10 Tilting mechanism

11 Quick-release strain relief

12 Current sensor (HALL converter)

13 Tactile height sensor

14 Control cable to the welding power source

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Claims (3)

Protection claims 1. Rail-supported assembly welding machine for welding materials which form a joint between them, whereby the machine * , an arc sensor is used to detect the joint path, !**!*; - the torch head is guided in the transverse direction and in the height of the seam according to the values determined by the arc sensor ⁴ _t J„' - the three-dimensional movement of the burner head to the joint is measured, *. J, _t · - all data processed in context, - saves the data for later use, - can control any MAG welding power source with a flat characteristic curve. 2. Welding machine according to claim 1, which all control and movement devices combined in one compact device, - is operated via a remote control panel (2). 3. Welding machine according to claim 1 and 2, - which enables the position of the burner head to be adjusted in relation to the arc base point via a tilting mechanism (10).