Is automated TIG welding economically viable?
When automating a TIG application, the first question to ask is the same as for any other automation: Is it profitable to use a robotic welding torch or a robotic welding cell?
To completely equip a robotic welding cell is a significant investment that usually only pays off in serial production with high volumes and in multi-shift operation. To ensure that this high investment pays off and that the profit is satisfactory, the cycle times of the robotic systems are optimized. Set-up and maintenance work should also always be considered, since the robot cannot perform during this time. A welding robot should be in permanent use so that it amortizes as quickly as possible.
Is experienced, well-trained staff available for the automated welding process?
One of the fundamental requirements in TIG welding, whether welding manually or with a welding robot, is the need for well-trained staff. Only those who have mastered the TIG welding process can ensure that the welding seams are executed by the robot in a qualitatively flawless way. Automated TIG welding is only different from manual welding in the sense that larger quantities are produced and the welding speed is higher. The Application and the parameters are almost the same.
For the correct implementation of the welding movement sequences using the robot, adequate programming knowledge for the respective welding robot must also be provided in order to determine the movements of the robot on the components and also the sequence of the weld seams for cycle-time-optimized production. Experienced welding staff is therefore essential for an automated TIG process.
What must be taken into consideration when programming the welding robot?
TIG welding is in itself a very clean process, but it is also much less resistant to errors. Due to the more concentrated arc, it is less forgiving of errors than MIG/MAG welding, which is fundamentally somewhat rawer. Therefore, when automating, it must be ensured that the programming is very accurate.
The programming of the robot welding torch is based on the TCP (tool center point), which must not change even when components are replaced on the torch system and the corresponding accessories. If the TCP changes due to a geometric modification of the existing setup, it must be reprogrammed.
The welding parameters correspond as far as possible to those in manual welding operation and, if necessary, are only adapted to slightly higher welding speeds. However, the speed must always be in the best possible relation to the quality.
What does the automated TIG welding cell look like?
To set up an automated TIG welding cell, you often need more space than for a manual welding booth. In addition, the following things belong to the TIG robotic welding cell:
- Safety enclosure including safety equipment to prevent access during automatic operation.
- Welding robot including control system
- TIG welding torch including hose package, power source and, if necessary, cold or hot wire feeding system
- Automated positioning system with adapted welding fixtures
- Supply lines for gas, pressured air, electricity and, if necessary, coolant
- External cooling system (if necessary)
- Fume extraction system (especially when welding stainless steels, welding fumes are produced that contain Cr-VI or nickel, which can be cancer-causing, therefore an extraction system is recommended for these applications)
- Important: Shielding curtains against direct and indirect view of the arc and its reflections on surfaces inside the welding cell.
Tip: Protect the welding cell from air circulation so that the shielding gas is not negatively affected.
Especially in terms of accessibility, but also in terms of plant availability, the TIG robot welding torch is of major importance. So-called change-neck torches are available in different geometries on the one hand and on the other hand allow a fast and, if necessary, automated change of the TIG torch.
With the additional use of a changeover unit, there are up to 5 torch heads in one rack. If different geometries are required or if a service is due (for example, replacement of the tungsten electrode), the changeover can be automated. Automated changeover is also no problem with liquid-cooled torches, as the cooling channels in the torch body are automatically locked during changeover. If wire feeders are used, they simply flip to the side.
The reproducibility of good welding results and the production of high volumes is a clear advantage of automated welding. If the accessibility of the workpiece for the automated process is ensured and the mentioned conditions are met, there is no further obstacle for the automated TIG process.
For the individual configuration of a TIG welding cell and the precise configuration for the workpieces to be welded, it is best to use a robotic system integrator. The initial contact for planning automation in the field of TIG welding can also be the manufacturer of the welding equipment or the robot.
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