Advancements In Automatic Orbital Welding Systems, Part 2
WELD REPEATABILITY, CONSISTENCY AND EFFICIENCY
The automated orbital welding process aids in achieving weld repeatability and consistency over extended periods of time. With manual welding human fatigue can become a factor. Although the operator may be highly skilled and experienced, he may produce inconsistent results because he literally is completing each weld by hand.
With orbital welding, the electrode is accurately rotated in an orbit around a joint on a rotor. The rotor and electrode are housed in the weld head, which rotates around the tube. The process is highly controlled, ensuring high-quality welds that can be produced on a consistent and repeatable basis. Orbital welding systems perform a set of operations in a controlled manner where variables are maintained at preset levels. The system automatically starts and completes the weld, stepping from one variable setting to the next at a specific location along the joint or at a predetermined time during the process. Advancements have been made to further help with weld consistency and operator efficiency.
Gas Control. Automated orbital welding generally uses the GTAW process, which operates by establishing an arc between a nonconsumable tungsten electrode and the base material that is being welded, creating a weld puddle. The electrode is positioned in the weld head. The electrode and weld puddle are both surrounded by a shielding gas, which is fed through the weld head to protect the electrode, molten weld puddle, and solidifying weld metal from atmospheric contamination. The heat produced by the arc melts the base material, and the electrode moves along the joint and progressively melts and joins the adjoining surfaces.
Newer orbital power supply designs feature automatic shield gas control to the weld head. Older systems require the use of a flowmeter to manually control gas flow to the weld held. Operators must adjust the flowmeter for different welds, allowing the possibility of human error when making changes and reducing operator efficiency if the flowmeter is not in the immediate vicinity of the weld location. Systems with automatic shield gas control eliminate this inefficiency or the possibility of negatively affecting the weld quality due to an incorrect setting. Forgoing a flowmeter, the controller adjusts gas flow automatically based on the program selected for a particular weld. The integrated flow controller also prevents users from initiating the weld without gas flow, an error that could result in damage to the weld head or the workpiece.
Blast Purge. Further gas control advancements enable operators to improve their efficiency when welding at locations where long distances exist between the power supply and weld head. A sufficient gas volume must be present at the weld location before starting a weld. In traditional orbital welding systems an operator may encounter a long wait for purge gas to reach the weld location. Newer welding systems utilize a blast purge feature to rapidly fill the lines and then automatically return gas flow to normal levels, allowing operators to start a weld sooner.
When choosing an orbital welding power supply, operators should look for systems that enable them to perform welds for a wide range of applications. They should also look for systems that limit electrical interference.
Higher Amp Outputs. Power supplies with higher power outputs are capable of welding larger diameter and heavier walled tubing and/or piping while maintaining consistent welds. Newer welding systems offer the power output needed to weld the heavier walled components found in general industrial applications like oil and gas while still having the ability to weld smaller diameter thin walled tubing for R&D or semiconductor applications.
Electromagnetic Interference. Initializing the welding process requires a high-frequency, high-voltage arc start, which could result in electromagnetic interference (EMI). EMI is an electrical disturbance that may cause interference with devices such as computers or other sensitive electronics. Frequent EMI resulting from a welding project could prove to be a nuisance or worse in the case of computers shutting down and causing work to be lost. Technology in arc starting has improved, and welding systems with low EMI arc start technology allow the arc start to occur without affecting the operation of equipment in close proximity. This allows for nuisance-free operation.
PORTABILITY AND ACCESSIBILITY
Small, lightweight orbital welding systems are a practical option for many industries, including welding contractors. Weld system power supplies can be moved easily from one job site to another. Remote controls and detachable weld heads and fixtures allow joints to be pre-positioned and enable orbital welding to be conducted in hard-to-reach places. There only needs to be enough clearance at the weld site to allow the weld head to make a full 360-degree orbit around the tubing. With manual welding, there typically must be enough clearance to provide the operator with full body access to the weld location. To gain access in plant settings, the manual method literally can require the dismantling of walls to provide the operator with enough space to make the weld.
As the world becomes a smaller place, a single welding system may be utilized across broader cultures and geographies. Perhaps the biggest cultural equalizer for a welding system is the ability for operators to use the system no matter what language they speak. Welding systems with multiple language capabilities built into the interface let users switch between languages at the touch of a button. The same welder can be used by a number of operators who can adjust the display to their native language and thereby improve their efficiency. Some welding systems also feature universal voltage input capabilities to automatically adjust to a country’s voltage input.
THE VALUE OF ORBITAL WELDING
Orbital welding is used in applications ranging from biopharmaceutical and semiconductor industries to petrochemical and power plants to chemical processing and refining operations. Orbital welding is finding increasing value because it can deliver highly repeatable, consistent and quality welds easier than ever before. Advanced technology is making orbital welding a cost-effective and viable option for plant managers, weld operators and others who have involvement in the welding process. The result is the ability to complete more welds per day compared to other processes and improve efficiency.
John Glessman is manager, welding system products, for Swagelok Company, 31500 Aurora Road, Solon, Ohio 44139, www.swagelok.com . He can be reached at email@example.com  or 440-349-5934.