IN THE LOOP: VALUE ADDED

Automatic orbital Gas Tungsten Arc Welding (GTAW) is utilized in a variety of industries where maximum leak integrity, high performance, or ultra cleanliness is of paramount importance. Automatic orbital welding systems enhance precision and reliability over manual techniques.

The advent of new technology has further improved these systems and made orbital welding practical for a range of applications. Small, portable inverter power supplies designed with open platforms provide welders of various skill levels with even more welding options and an ease of use not previously available. Improved programs and controls help improve the consistency and reliability of welds as well as operator efficiencies.

A closer examination of these advances reveals why automatic orbital welding applications continue to expand diversely through the biopharmaceutical and semiconductor industries, to petrochemical and power plants, to chemical processing and refining operations.

OPEN PLATFORM DESIGN
Orbital welding power supplies are incorporating more skills of the welder into the welding system itself, enabling efficiencies in automation, programming, and documentation.

To achieve these efficiencies, a power supply must be designed with an open platform that allows an interface with standard devices and the ability to expand as technology evolves. The result is a welding system that meets the expanding needs of various industries:

Automation
Aspects of the welding process that historically would be undertaken manually, such as travel speed, arc gap, current control, and gas flow are now controlled through electronic and mechanical means. This minimizes many of the variables in the welding process that can lead to errors or defects and enable welders to focus most of their attention on overseeing the process and completing actual welds.

The result is a more efficient and streamlined welding process that raises productivity as well as weld consistency and quality.

Programming
Every orbital weld – regardless of the application – requires the creation of a program to control the output characteristics of the system. User-friendly systems simplify programming by providing step-by-step procedures to create programs for a variety of tube diameters, wall thicknesses and base materials.

Rather than build programs manually using charts or tables, assessing past weld parameter data, or relying on memory, the operator can create a program by selecting pertinent data from "pick lists" or dropdown menus. The system then creates the initial program for the operation, which can significantly reduce the chance for human error and reduce start-up time.

This is also very helpful when welding materials are unfamiliar to the user. If additional assistance is needed, a quality orbital welder supplier can offer support in developing welding programs.

Newer orbital welding systems offer numerous preset programs and heightened user interfaces for programming ease. Models are available with integral USB ports that allow operators to plug in a keyboard, mouse, and/or a number keypad for easier data entry. Operators may also download welding programs via a USB flash drive or update operating system software to add features or functionality. Durable, integrated color touchscreens provide visual programming aids.

Documentation
In some industries, documentation of the weld is important for quality assurance and control. Traditionally, this documentation process is costly and time consuming, requiring weld operators to maintain detailed, written weld logs that must be entered into databases and formatted into reports.

But modern orbital welding technology enables this data to be stored within the system for retrieval and transfer to databases for analysis and reporting. Data management gives an organization the ability to track trends, review production rates and calculate costs per weld to ultimately help improve efficiency, lower costs, and bid more accurately on welding jobs.

High-speed thermal printers built into newer orbital welders also help with documentation. For example, users can print a hard copy reference of weld parameter details for documentation purposes.

Based on procedural requirements, operators may need to "coupon in" by creating a schedule, completing a weld, examining it for quality, and documenting these actions by printing the coupon. At specified intervals, the operator will perform similar actions to "coupon out." Coupon printouts provide a record of verification to meet quality control requirements.

WELD REPEATABILITY, CONSISTENCY AND EFFICIENCY
Human fatigue can become a factor with manual welding. Although the operator may be highly skilled and experienced, he risks producing inconsistent results because each weld is literally completed by hand.

The automated orbital welding process achieves weld repeatability and consistency over extended periods of time because the electrode accurately rotates 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 entire process is tightly controlled to produce high-quality welds on a consistent and repeatable basis.

A controlled set of operations is performed to maintain variables 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. Technical advances here have further improved weld consistency and operator efficiency:

Gas Control
Automated orbital welding generally uses the GTAW process that establishes an arc between a nonconsumable tungsten electrode and the base material being welded to create a weld puddle.

The electrode is positioned in the weld head. The electrode and weld puddle are both surrounded by a shielding gas that 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 as the electrode moves along the joint and progressively melts and joins the adjoining surfaces.

Older systems use a flowmeter to manually control gas flow to the weld held. Operators must adjust the flowmeter for different welds, risking potential human errors in making changes and reducing their own efficiency if the flowmeter is not in the immediate vicinity of the weld location.

Newer orbital power supply designs use automatic shield gas control to the weld head to eliminate human inefficiency or the potential of incorrect settings. 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 damage the weld head or the workpiece.

Blast Purge
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 automatically return gas flow to normal levels, allowing operators to start a weld sooner. This can improve operator efficiency when welding at locations where long distances exist between the power supply and weld head.

POWER CONSIDERATIONS
When choosing an orbital welding power supply, operators should look for systems that can 1) perform welds for a wide range of applications and 2) limit electrical interference.

Higher Amp Outputs
Power supplies with higher power outputs can weld 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 small diameter thin-walled tubing for R&D or semiconductor applications.

Electromagnetic Interference
Initializing the welding process requires a high-frequency, high-voltage arc start that may generate electromagnetic interference (EMI). EMI is an electrical disturbance that can interfere with computers or other sensitive electronic devices. Frequent EMI generated by a welding project could be a nuisance, or worse, it might shut down computers and cause work to be lost.

Arc starting technology has improved into a nuisance-free operation. New welding systems with low EMI arc start technology permit the arc start to occur without affecting the operation of equipment in close proximity.

PORTABILITY AND ACCESSIBILITY
With manual welding, there must typically be enough clearance for the operator to have full body access to the weld location. To gain access in plant settings, manual welding can literally require the dismantling of walls to provide the operator with enough space to make the weld. For this reason, small, lightweight orbital welding systems are a practical option for welding contractors and other industries.

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. The weld head only needs enough clearance at the weld site to make a full 360-deg orbit around the tubing.

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 each adjust the display to their native language to improve their efficiency. Some welding systems feature universal voltage input capabilities that automatically adjust to a country's voltage input.

THE VALUE OF ORBITAL WELDING
Orbital welding is increasing in value because it delivers highly repeatable, consistent and quality welds easier than ever before. Advanced technology makes it a cost-effective and viable option for plant managers, weld operators and others involved in welding to complete more welds per day and improve efficiency compared to other processes.

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John Glessman is the manager of welding system products for Swagelok Company, 31500 Aurora Road, Solon, OH 44139, 440-349-5934, john.glessman@swagelok.com, www.swagelok.com.