The manufacturing challenge of improving productivity while maintaining quality and keeping costs in check affects every industry, and welding is no exception. Novarc Technologies created their collaborative welding robot, the Spool Welding Robot (SWR), to automate the welding process in order to improve productivity on the shop floor and reduce costs for the pipe fabrication shop.
The SWR uses a floating long-reach manipulator with a 3-axis robotic arm at the end that works with an operator to increase their dexterity and flexibility. It is designed specifically for pipe, small pressure vessel and other types of roll welding, and is capable of welding flanges, Ts, elbows, reducers and more.
Implementation of the SWR has shown a three to five times increase in pipe welding productivity, potentially allowing the cobot’s capital cost to be recovered in an average of six to 18 months. Even with this outcome – and impressive results like that at Vancouver Drydock, where productivity was increased by more than 400 percent using the SWR – Novarc continued to undertake further research to develop ways to expand the capabilities of the SWR for pipe fabrication shops.
The result was the development of new SWR+HyperFill technology, which increases heavy fabrication productivity by increasing weld deposition rates while delivering excellent weld quality.
The SWR+HyperFill design uses Lincoln’s STT GMAW-MWSC process on the root pass, and twin wire GMAW-P (HyperFill) on the fill and cap passes. It is a highly efficient, fully integrated dual-torch system. It can be used on carbon steel pressure pipes or vessels with 0.5 in. to 2 in. thickness and as small as 6 in. in diameter. The system also has the flexibility of using root-to-cap GMAW or seamlessly switching to flux-core arc welding (FCAW) or metal-core arc welding (MCAW) for the fill and cap passes.
Novarc introduced SWR+HyperFill to the market this spring after doing extensive research and conducting a productivity study to review the capabilities. The evaluation compared Novarc’s mechanized SWR, integrated with STT GMAW-MWSC and GMAW-P (HyperFill) twin-wire technology, against typical traditional welding (baseline) processes such as manual (SMAW), semi-automatic (GMAW) and mechanized (SAW). Productivity studies were done in an actual shop production environment following typical practices and welding procedure specifications.
In order to evaluate welding productivity, costs, quality and efficiencies, some companies use sophisticated programs based on specific applications and equipment, while others just use rough estimates. However, an accurate assessment demands that a full range of deposition rates, efficiencies and duty cycles be considered.
In the Novarc study, three major factors were considered to simplify the relative comparison of welding and automation technologies:
- Duty cycle – the ratio (percentage) between arc time and the total time spent by the welder or welding operator completing a joint.
- Deposition rate – a measure of the rate of weld metal deposition (lb./hr or kg/hr) for the welding processes and/or automation system.
- Deposition efficiency – the ratio (percentage) of weight of deposited weld metal as compared to the weight of filler metal consumable used.
The results of the comparison found that substantial productivity improvements can be realized on the shop floor with the SWR+HyperFill platform. Improvements in deposition rate, deposition efficiency and duty cycle, compared to the baseline processes, were consistently achieved, demonstrating that the system is capable of reducing welding times, achieving higher production rates and excellent weld quality when compared to traditional pipe fabrication shop practices.
Besides achieving higher deposition rates and deposition efficiencies, SWR+HyperFill can increase factored diameter inches to 350 to 500 per shift on carbon steel pipes, meeting ASME Section IX and B31.3 WPS qualification requirements and achieving high toughness test results down to -50 degree F (-45 degree C).
With the SWR+HyperFill solution, there are a number of benefits beyond the original features of the SWR (e.g., small footprint, integration with up to five positioners, assisted seam tracking and height control, welding vision system NovData). These include:
- Deposition rates of 15 lbs./hr or higher on fill and cap passes
- The root, fill and cap passes can be welded for up to 2.5-in.-thick materials in the same welding cell as the SWR
- Flexibility to use GMAW or MCAW on the root
- Flexibility to use FCAW or MCAW on the fill and cap passes instead of HyperFill (with the right tip and drive rolls)
- Flexibility to weld stainless steel with the second torch (with the right tip and drive rolls)
- Elimination of the hot pass common with manual or semi-automatic welding
This research determining the expanded capabilities of the SWR+HyperFill system is very good news given that pipe welding is an integral process to myriad construction projects all over the world. If modern welding and automation technologies are implemented over some traditional welding practices, then pipe fabrication shops are guaranteed higher performance, specifically in deposition rate, deposition efficiency and duty cycle, resulting in a higher return on investment.
Practically speaking, this means these shops will be able to increase their heavy fabrication productivity by increasing weld deposition rates and delivering excellent weld quality; lower their cost by reducing weld and material handling costs compared to the sub-arc process; and streamline and simplify production.
As for the bigger picture, this automation technology helps highly skilled welders extend their careers, and it allows other workers to do the jobs that previously only highly skilled welders could do by working alongside the robot.
Filling the labor gap is key as the severe global shortage of highly skilled welders impacts numerous industries such as oil and gas, building construction and shipbuilding. Pipe fabrication shops serving these global industries require highly skilled welders, and according to the American Welding Society, this is a looming labor crisis that will escalate to a shortage of about 300,000 welders by 2024.
Pipe fabricators and mechanical contractors with customers in a number of industries that are faced with this labor skills gap, and are consistently pressed to increase margins on existing projects, can now confidently bid with increased competitiveness on new projects. This is good news for all the players.
The Lincoln Electric Co.