by Bill Atkinson
As the capabilities and technology of welding systems have continually progressed, more and more companies are considering the implementation of orbital welding as a cost effective alternative manufacturing and fabrication process. For companies that plan to include orbital welding to their workflow, some background and basic operating fundamentals can assist you with the selection of the right equipment for the job.
Originally, orbital welding systems were designed around a single process and dedicated to producing repeatable, accurate results for a specific application. To the industries that embraced orbital welding to join tube and pipe, the advantages offered in terms of performance and reliability were obvious and orbital welding was rapidly adopted as a preferred manufacturing capability.
Orbital welders come in a wide variety of configurations and types as welding systems became more sophisticated and versatile. The process of orbital welding can now be utilized in many manufacturing roles where components need to be rapidly and repeatedly fabricated with dependable quality and consistent precision beyond conventional pipe welding.
Orbital welding systems designed to work in conjunction with tube cutting machines for joining electropolished ID stainless tubing through autogenous butt welding have become an integral part of the construction and maintenance of high purity tubing and process piping systems for food and beverage, petrochemical, semiconductor, and pharmaceutical industries, just to name a few. Excellent arc control produces uniform weld fusion while preserving the integrity of the ID bore so that weld points do not present a contamination source.
Orbital welding systems can provide welding in open or closed chamber configurations depending on the weld requirements and the desired method of purge gas control required. In addition to chambers for purge gas typically formed on the OD of the weld surface, many successful internal chamber techniques and internal alignment clamps that include purge dam capabilities exist to ensure quality welds through effective oxygen reduction.
Special mechanized orbital pipe welding systems are available with single and multiple heads that are producing significantly higher performance in terms of weld head travel and filler metal deposition rates. These productivity increases are an extremely important factor for midstream production in the oil and gas industry, land based and offshore pipeline production, and for municipal and commercial piping infrastructure maintenance and construction projects.
Many industrial orbital welding systems are employed for the fabrication of primary structures that will be employed in oil exploration and production. Much of this fabrication is conducted onshore with the structures being transported to their place of deployment. The joining of pipeline sections in onshore “fab-yards” also decreases the level of offshore joining required.
Today’s systems offer the welder unprecedented levels of control with some systems offering the remarkable ability to sense the current properties of the arc in real time. Using advanced algorithms and stored data, these systems can moderate and adjust the current at incredibly fine increments to achieve essentially perfect welding results on small and thin-walled components up to heavy weld profiles with complex “J” and compound bevel geometries.
In a world short on welders, the degree of programmable control and precision offered by today’s welding systems empower a new generation of operators to routinely produce welds that would have been nearly impossible for even the most accomplished welders using the unmechanized equipment of the past. This is especially true today with difficult to weld exotic alloys and increasing requirements for compliance to welding codes and certifications.
Programmable weld controllers offer the ability for companies to develop weld procedures and record and store proprietary welding process instructions and parameters in program files that can be cataloged, retrieved, and digitally distributed throughout the enterprise.
Companies that are introducing orbital welding into their workflow have many more options and equipment choices than ever before. The proven results and success of orbital welding equipment is demonstrated by the wide range of specialized equipment available and the number of orbital welding equipment manufacturers.
Key to choosing an optimal orbital welding system for your business is to thoroughly evaluate your present requirements, while also factoring in what additional welding processes might be desirable on an on-going basis to maximize the versatility of your welding operations.
Gaining a comprehensive understanding of all the features and benefits offered by the wide variety of today’s welding systems can be a daunting task. A good starting point is to consider some of the essential operational aspects of these systems, and how they can benefit you.
Here is a list of ten key points to look at when investing in today’s orbital welding equipment.
1. Power – An ideal welding system needs to be versatile enough to cover a broad range of applications, with a power level to thoroughly bracket your needs. Systems that provide a wide range of operating currents will be more flexible and will provide weld development over a wider range of sizes, material types and weld thicknesses. In addition, different welding processes require varying degrees of power for optimal operation. Power levels also need to be considered when applications for orbital welding require high levels of travel and deposition.
2. Control – Orbital welding can be degree, length or time based, and digital weld controllers that offer more than one of these modes of operation can offer increased choice to best fit the application. Some basis of control is more prevalent in different areas of the world than others. Having a choice of control modes allows the welding system to better address the mode that is more familiar or offers operator options to best correspond with a specific application.
Another important manual aspect of control is provided through a pendant controller that greatly increases direct interaction with the welding process. A well designed, user friendly pendant provides the capability to monitor values and adjust the weld control program immediately without having to enter those settings into the main control unit. The controller should keep track of those modified inputs for further evaluation.
This interaction is further enhanced by the controller’s ability in some systems to sense and monitor the welding arc characteristics in real time and make immediate changes to produce welds of amazing quality and repeatability.
3. Availability of Parts – Orbital welding is a considerable investment that can yield ongoing cost and time savings. One factor in ongoing operating costs of a welding system is the availability and nature of component parts. Welding is a process that places extreme demands on working components through the heat, smoke and spatter present in the operation. Many parts that are exposed to these factors degrade over time and wear at an enhanced rate. A welding system that has been designed to utilize standard, readily available parts is a system that will be much more cost effective to your business.
4. Multiple Processes – When discussing any form of orbital equipment, one of the prime factors to consider involves the modes of operation required for your welding operations. Mechanized processes offered in orbital welders typically include GTAW, GMAW-S, GMAW-P, and FCAW. Any single welding system that provides multiple welding processes offers increased versatility to perform a wide range of work requirements, or to combine those processes in multi-process procedures that can be extremely important to productivity.
5. Flexibility – Flexibility in orbital welding can be defined in terms of (in multi-process systems) the time required to reconfigure from one process to another. Can this changeover from GTAW to GMAW for example, be performed without removing the weld head from the mounting track. In some systems this changeover can be accomplished in just a few minutes. Mounting rings for orbital weld heads should compensate for variances in pipe diameter produced by heat transfer from the welding process. Rings should work with several different pipe sizes to reduce the number of mounting rings required to cover the pipe sizes you work with. A flexible welding system can deal with process changeover without the need to purge gas lines due to having discreet gas inputs for different gasses.
6. Safety – Due to ever increasing concerns in the workplace, the hazardous nature of hexavalent chrome exposure, flux fumes and other products of the welding process are being monitored and regulated more than ever before. Welding systems with advanced circuitry to reduce smoke and produce less spatter offer greatly reduced exposure levels that can improve the operator’s working conditions, save time through reduced compliance measures, and ensure a safer, healthier workplace.
7. Performance – Orbital welding systems are available that perform with unprecedented levels of weld deposition, significantly impacting reducing project costs and time. Best of all, today’s high performance systems have proven that they can deliver very high travel and deposition rates while maintaining critical weld integrity and welding procedural compliance.
8. Weld Procedures – The weld controller is where computer technology makes its greatest contribution. The “programmability” of mechanized welding incorporates the ability to define a weld procedure, either a subset of instructions for a individual process or a comprehensive, dynamic program that contains all of the stages of the weld from the root pass to the cap pass. The controller interface works with the welder to provide a practical, reliable means to precisely direct the mechanized weld head, through control inputs for speed, duration, and current properties to perfectly complement the weld profile and material being joined. The ability to loop, chain and link program elements is extremely beneficial to effective program development. When QC procedures are required, controller screen monitoring and modification screens, combined with the ability to save and print that data, facilitate procedural compliance.
9. System Configurability – Modularity is another aspect of orbital welding where specialized mounting can be designed to convert the welding system from an orbital configuration to a weld cladding system. In addition, the capability to easily convert the weld head from ring mounting to flat (track) mounting, as would be required for joining flat or curved plate, adds a tremendously beneficial configuration and operation option to any orbital welding system.
10. Ease-of-Use and Training – Inherent ease of use is a goal of any advanced welding system. Simple, logical input screens, logical (familiar) welding symbols and references, and an effective control pendant feature all aide the welder while learning the nuances of a new welding system. All of the features of a comprehensive and well designed welding system need to operate together effectively for the system to be easily mastered by the operator. A reasonable learning curve is a primary benefit. Some equipment manufacturers offer excellent (free) customer training and support programs to effectively exploit all of the system advantages.
As you can see, today’s advanced mechanized orbital welding systems offer a wide range of dynamic features and processes that provide more control, versatility and reliability than ever before. Implementing one of these high performance orbital welding systems into your workplace will ensure that you get repeatable, quality welds for increased productivity, time and cost savings.