Mobile Navigation

Future solution

Robotic TIG cladding: Addressing the quality and productivity conundrum

When it comes to cladding operations, consistency, quality and speed of delivery for suppliers to the energy and oil and gas industries is key. Since pre-Covid days, it’s becoming apparent a declining number of new project awards will be the norm until the next oil and gas super cycle. With this, an even more competitive landscape is expected to open up new doors to technology. This is where robotic cladding could pave the way to even more success and profitability for industry suppliers.

The TOPTIG design feeds the filler metal directly through the nozzle into the arc at an optimal angle to the tungsten electrode. The precise wire angle and flexible robotic arm provide the capability to deliver the TIG wire into the arc at higher temperatures.

Regularly lauded as high-quality processes, both TIG welding and TIG cladding are readily adaptable to materials of all types and service conditions within the diverse energy and oil and gas industries. Today’s conventional cladding process requires constant operator attention and interaction. While this has been perfected over many decades in the industry, little has changed in terms of a new breakthrough solution. The use of conventional TIG cladding operations remains highly labor intensive and time consuming.

Conventional mechanized TIG operations have improved over the past decade, primarily focused on single-wire, and sometimes multiple-wire, operations. Manufacturers squeeze the inherent process limitations to achieve results similar to their industry peers, which ultimately has an impact on bid competiveness, productivity and profits. 

That’s where automation and new ideas for innovation and solutions come into play. Robotic TIG welding systems, such as Lincoln Electric’s TOPTIG, already have proven themselves. TOPTIG, for example, combines quality with speed, increasing operational efficiency up to 300 percent for some users in welding applications. They achieve this by increasing the arc-on time, travel speeds and deposition rates, while achieving higher quality and improved bead appearance.

The same values of TOPTIG welding are being investigated and developed for cladding in a number of industries that rely on clad materials in their final product. With this, ongoing development will help operators eliminate common TIG cladding challenges in a way that simply wasn’t possible before.

Cladding challenges

The components of a TOPTIG robotic TIG welding system.

Cladding by itself often strains budgets and the contractor’s ability to meet short notice demand quickly and consistently. TIG cladding requires precise coordination and placement of the wire at the correct travel speed and amperage. The key limitations are commonly the position, wire feed speed, constraints of chemistry and compliance with third-party or industry standards. Conventional TIG processes and wire delivery have been optimized over the years, but still more room for improvement is possible particularly in the areas of increasing deposited weld metal and reducing operator intervention.

Speed is limited by the position and maximum available wire feed speed in order to maintain chemical, hardness and surface condition properties. Robotic TIG cladding is expected to offer the advantages of precise control and integration with coordination motion to optimize the surface position during cladding, while increasing deposited material. For cladding operations, achieving a single-wire deposition rates exceeding 300 ipm with 0.045 wire using the power source waveform control with robotic controls would be an increase of 25 to 50 percent above conventional deposition rates.

This is particularly beneficial when using the common alloys used in the energy and oil and gas industries. Precise positional control of the part, as well as the accuracy of wire delivery in the TOPTIG robotic system has been proven in welding. The same result is expected for cladding.

Takes skill

The challenge of cladding and welding operation is exacerbated by the ongoing skilled labor shortage, which includes all levels of ability. A large number of experienced welders and operators are retiring and a smaller number of new workers are entering the workforce. Combined with many other factors, this means the labor pool falls short to support the need. Unfortunately, without an increase in skilled manufacturing employees, it’s only going to get worse. The American Welding Society estimates there will be a shortage of nearly 400,000 welding operators by 2024.

Experienced TIG operators are even harder to find these days. The precision of the TIG cladding process demands knowledge and experience to deliver precise wire placement in the weld puddle at the correct travel speed and amperage on high-cost parts. Compounding this is finding operators who are capable of achieving a good result in out-of-position cladding applications where small changes can have serious impacts to the final results. This is evident in internal bore cladding out of position, where cameras and constant monitoring of the arc is required at each station.

Mistakes and rework can add up quickly. Robotic TIG cladding provides the opportunity to close the skills gap and deliver consistency and precision 24/7 with trained operators who may be able to monitor multiple cells all at once.

Meeting expectations

Once the exception, robotic systems that are easy to learn and use are more commonplace. While robotics is viewed as a high technology offer to many industries slow to change, robotic TIG welding (and future cladding adoption) lines up with the trend in many other industries and applications, where machine learning and a “push of a button” is the expectation. Today’s workforce is geared toward this expectation in their personal and professional lives, so industry continues to adapt. 

Today, manufacturers are willing to invest in cost-effective, fully integrated, easy-to-program TIG process solutions, such as Lincoln Electric’s patented TOPTIG Fab-Pak robotic cell, and the same is expected to be true for cladding applications.

Programming options for fully automated robotic TIG systems combine precise torch placement with easy-to-teach pendant controls to exceed many mechanized TIG system capabilities. Optimized bead geometry and layers can be deposited over the base metal with the right chemistry and precise penetration profile to control dilution.

TOPTIG is offered as a complete, ready-to-use robotic package. It is a proven solution for welding now emerging as an option for future cladding operations. In both cases, the system incorporates Lincoln’s PowerWave platform and the patented TIG wire delivery design. 

This unique design feeds the filler metal directly through the nozzle into the arc at an optimal angle to the tungsten electrode. The precise wire angle and flexible robotic arm provide the capability to deliver the TIG wire into the arc at higher temperatures. This allows for faster wire feed speeds (deposition rates) and faster travel speeds compared to manual and most mechanized TIG cladding systems. By increasing the transfer of deposited filler metal (or clad material) across the arc, cycle times for the same parts are reduced. 

By adjusting flexible parameters with the robotic controls, operators can accommodate different joint types, materials and positions, including choosing between different droplet transfer modes. Users also can elect to pulse and synchronize the output current, which results in near-perfect surface appearance. They also can quickly change out the tungsten without disassembling the torch, which adds to the speed factor.

Older, conventional systems with add-on TIG torches convey filler metal using an external guide tube, positioning the wire at an angle approaching 90 degrees relative to the electrode. This can cause issues with access, positioning and reliability, even at slower travel speeds and deposition rates. 

On the other hand, the integrated wire delivery in the nozzle of robotic TOPTIG systems has a compact profile that allows operators to have greater access to the base metal and use multi-directional programming, which is a plus in pipe cladding applications. The wire feed design allows precise, repeatable wire placement where energy is most efficient, reducing spatter and distortion and helping to provide even coverage, even at faster travel speeds.

Final delivery

Simply put, here’s what a robotic TIG system delivers:

  • Consistent quality – gives manufacturers the flexibility to deliver quality at production speeds that would be impossible for manual and some existing mechanized TIG systems to achieve.
  • Increased productivity – justify the cost of a robot by examining the productivity gains the company would experience versus what is currently achieved with manual or mechanized cladding systems.
  • Decreased scrap and waste – the precision of cladding robots exceeds an accuracy level of 0.0001 in. (0.00234 mm). Welding paths are also programmed to handle some part variation. This means easily reducing the number of sub-par parts and scrap rates. This also can help stay on track with budget and profitability.
  • Better return on investment – switching to robotic TIG cladding (or welding cells) will help reduce labor and materials, while increasing repetitive quality. A higher throughput rate also speeds up the payback period.

While robotic TIG cladding won’t completely replace everything existing systems bring to the table, it does present a new and exciting future opportunity to operate at a higher level of productivity with repeatable processes, delivering substantial gains in quality, productivity and profitability.

The Lincoln Electric Co.

Comments

Comments powered by Disqus.