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.