The shipbuilding industry has long felt the demand to increase its production rates. Ships, however, are massive, complex structures with specifications that become more stringent by the day. Shipbuilders are being asked to reduce the time and cost associated with their processes, while also being expected to enhance precision and structural integrity. To say the least, the stakes are high.
Welding, a fundamental part of ship construction, is one area where innovative equipment solutions can make a difference. Impacting everything from hull integrity to operational performance, the range and complexity of welding requirements necessitate a move beyond traditional methods that are often insufficient. Fortunately, other welding solutions are available that can make a significant difference.
Traditional welding methods used in shipbuilding and heavy fabrication are wide ranging and include multiple welding processes for different elements of a ship. These welding processes are performed manually or semi-automatically with mechanical systems.
However, a different class of automated welding system – one that is intelligent and adaptable – offers a different approach. Lincoln Electric’s Inrotech-Crawler fully automated welding solution is a mobile, multi-axis robotic welding system designed for long, complex, multi-pass welds on large plate and thick profile structures, where geometry varies significantly due to fit-up tolerances, distortion and scale. The solution continuously senses and adapts to these geometric variations and distortions.
The Inrotech-Crawler’s forte is replacing – or reducing reliance on – the most common manual and semi-automatic welding solutions, which require significant manual intervention, pre-programming or re-setup when geometry changes. They include:
- Manual multi-pass welding (stick, flux-cored, solid wire MIG-MAG)
- Semi-automatic welding tractors
- Simple mechanized track-based welding systems
Adapting in real time
In addition to reducing or totally eliminating reliance on manual or semi-automatic processes, several key benefits make the system an attractive solution for shipbuilders looking to enhance their multi-pass welding capabilities. These include reduced cycle times, consistent weld quality, enhanced worker safety and exceptional flexibility.
Flexibility allows the system to adapt to various welding tasks and materials, making it suitable for diverse applications within shipbuilding.
Additionally, the Inrotech-Crawler is equipped with advanced monitoring systems that provide real-time feedback during the welding process. This real-time sensing allows for adaptive parameter adjustment, ensuring consistency and quality in every weld. The data collected during the welding process can also be useful for future projects, enabling shipbuilders to continually refine their techniques based on facts.
The Inrotech-Crawler’s ability to perform fully automated welding also eliminates many of the labor-intensive aspects associated with traditional welding methods. This reduces the margin for human error and allows for a much faster turnaround time on jobs. It also reduces dependence on highly skilled welders for repetitive, heavy welding.
Advances in the shipyard
Seaspan’s Vancouver Shipyards recently implemented the new welding technology, starting in the panel shop where the Inrotech-Classic version is used primarily for fillet welding on T-beams. In the block assembly shop, the more advanced Inrotech-Crawler is used for groove welds where steel plates are butted together to form long structural seams.
This version scans and assesses the joint and only proceeds if the weld can meet welding procedure specifications.
“If it doesn’t think it can do a proper weld, it won’t do it,” says Vincent Mak, welder chargehand, Vancouver Shipyards. “That’s actually a positive from a quality control standpoint. It might mean we need to adjust the fit of the plates or the way we need to sequence welds prior, but the end result is a weld that meets our standards.”
The Inrotech-Crawler in the block assembly shop recently completed its first job. Finding the balance between automation and human workers is central to how the new technology is being used in the yard.
“When the Inrotech-Crawler completed its first job in September, one of the biggest surprises was the positive reception from the workforce,” Mak says. “Honestly, I expected more pushback. But most folks have been very supportive. We have so much welding work to do, especially with work on the polar icebreaker underway. The new equipment is being seen as a tool rather than a replacement for skilled welders.”
Mak is referring to the heavy polar icebreaker currently under construction at Vancouver Shipyards.
Richard Leech, director of manufacturing at the shipyard, noted automation is a continuing focus.
“As projects like the Multi-Purpose Icebreakers move forward, we continue to search for automation solutions while fully optimizing the tools we already have,” he says. “Planning is key to automation success; looking ahead at the builds and sequencing to fully use the equipment at each stage. There’s an amazing opportunity here to work together across planning, engineering, production and quality teams to keep moving automation and efficiency forward, especially on future projects.”
Combining advanced automation with workforce expertise is driving innovation and building the skills needed for future shipbuilding. The new welding technology is helping achieve this by empowering skilled trade workers instead of replacing them.
The logic of it
The intelligence behind the welding technology is Lincoln Electric’s Inrotech-WeldLogic software. Based on years of accumulated experience in manual and robotic welding, the software automates complex multi-pass welding with adaptive planning, precision, consistency and minimal operator input. The Inrotech-Crawler goes from a simple motion system to an autonomous system capable of scanning, analyzing and executing welding sequences based on the real geometry of each weld pass on the fly.
The operator’s role is intentionally simplified. To initiate a new welding job, they only have to provide basic inputs via the intuitive HMI, such as material type and thickness, groove type and orientation, wire and gas. This ease of use allows a single operator to supervise multiple Inrotech-Crawler units simultaneously, significantly increasing productivity and reducing manpower costs.
To begin, the Inrotech-WeldLogic system uses a laser scanner to automatically measure and identify the actual groove geometry. The WeldPlanner, the central computational module of the system, processes this scanned data and calculates all relevant welding parameters. These include:
- Number and location of weld passes
- Layer heights, weaving patterns and torch angle
- Welding speeds, amperages and voltages
- Adaptive parameter adjustments based on groove position, tolerance variations and interpass temperature
This foundation allows Inrotech-WeldLogic to dynamically adapt welding parameters in real time, adjusting seamlessly to variations in groove geometry, which are a frequent challenge in heavy industrial welding. This ensures uniform weld quality and repeatability, even when dealing with irregular or large-scale structures such as ship hull sections.
Multi-pass challenges
In advanced welding applications, particularly for multi-pass joints, precision and repeatability are critical. For every weld pass, temperature, groove geometry and deposition rate must all be monitored and controlled. Any small deviation, such as excessive interpass temperature or variable bead height, can lead to internal defects, lack of fusion or inconsistent penetration.
The Inrotech-WeldLogic sequence eliminates these risks by providing real-time scanning, automated cleaning and the adaptive recalculation between each pass. By re-scanning after every weld deposit, the system updates the groove geometry and corrects for even microscopic deviations caused by heat distortion or filler accumulation. This ensures consistent penetration and bead formation across all layers, even on multi-pass welds up to 6 in. (150 mm) deep.
This adaptability is particularly important when dealing with deformations that occur during welding. The system’s sensors detect these changes and adjust parameters, such as welding speed, weaving amplitude and bead positioning, without interrupting the process.
The system also streamlines multi-job welding. For projects involving numerous shorter welds, the multi-job mode can facilitate splitting up a weld groove into more segments to plan an optimum weld sequence with respect to heat-related deformations.
This approach eliminates the need for precise workpiece placement. Joints only need to fall within the robot’s reachability, which significantly reduces setup time.
Answer to complexity
Inrotech-WeldLogic’s versatility makes the Inrotech-Crawler highly attractive across various heavy industries, including shipbuilding, offshore construction and other large-scale manufacturing. The system’s ability to adapt to changing geometries ensure it meets the demands of even the most complex projects. The technology brings measurable benefits across productivity and quality metrics:
- Time savings: Automated planning and execution reduce setup time dramatically.
- Quality assurance: Every pass is planned according to exact geometry, ensuring compliance with the customer’s WPS parameters and minimizing human error.
- Process consistency: Intelligent monitoring and parameter adaptation maintain uniform quality over long welds and complex geometries.
- Operational simplicity: No offline programming or robot teaching required.
As global competition intensifies in the shipbuilding industry, the need for high-quality, efficient production methods becomes ever more critical. The introduction of intelligent automated welding solutions represents a pivotal shift toward improved operational efficiency and quality assurance. The Inrotech-Crawler addresses unique welding challenges with efficiency, quality and adaptability. Cutting-edge technology like this not only meets the current demand but also paves the way for future advancements in shipbuilding processes.
To explore more about shipbuilding and heavy fabrication, Techgen Media has an archive of structural articles to check out.
