Although the Korean shipbuilding industry is experiencing a resurgence often referred to as its “second golden age,” it continues to face challenges in securing skilled labor. While the gap is partially filled with foreign workers, tasks like welding require extensive training due to the need for expertise and craftsmanship. Furthermore, once workers become proficient, many leave due to visa or residency limitations.
To address this, HD Hyundai Samho has adopted collaborative robots for welding automation. Welding is a critical process in shipbuilding, directly impacting structural integrity and overall vessel quality. HD Hyundai Samho, a global shipbuilding and marine company constructing over 50 ships annually, chose robotic welding automation as a way to reduce labor intensity and increase production efficiency.
JCT, a partner specializing in welding systems, joined this project. As a robotics automation company with strong expertise in component technologies and system integration, JCT delivers customized solutions using Rainbow Robotics’ RB series collaborative robots across factory automation, logistics, and service robotics. Beyond robotic systems, JCT also integrates various automation components such as PLCs, HMIs, and sensors to provide comprehensive SI solutions. With experience in both industrial and collaborative robots, JCT identified the RB series as the optimal choice for this process and supplied the solution to HD Hyundai Samho. Unlike industrial robots that require safety fences, collaborative robots can work alongside human operators without additional enclosures, offering greater efficiency in space and cost.
Welding ensures the strength and stability of ship structures. Previously, welding was done manually or using carriage systems. However, securing additional manpower became difficult, and carriage systems could not achieve full automation. These systems follow straight paths but struggle in closed or confined spaces due to limitations in welding start and end points.
Recognizing the need for flexibility and precision in constrained environments, HD Hyundai Samho adopted Rainbow Robotics’ RB3-730 collaborative robot. This decision enabled high-quality welding even in tight shipyard blocks, overcoming the limitations of carriage welding. Furthermore, the company is actively researching the use of collaborative robots in curved block welding applications to maximize their advantages.

A Portable Welding System with Mobility and Precision

The RB3-730, a compact high-precision collaborative robot, features an S-shaped arm configuration ideal for complex contours. Its three wrist joints rotate through a common point, allowing for precise and efficient movements. These structural benefits make the RB3-730 widely suitable for welding automation.
With a payload capacity of 3kg and a weight of 11kg, it is well-suited for mounting welding torches. Using these features, a portable welding system was developed that workers can carry directly. The magnetic robot base provides stable support during welding, while handles on both sides of the 14kg total system (including the robot) allow easy transport and ergonomic handling.

Precision Welding Enabled by Built-In RB Software

The RB series offers the most built-in functionalities among collaborative robots in its class. These features are standard capabilities provided by the manufacturer, enabling use across various processes without the need for additional programming or costs. In particular, advanced welding automation software such as seam tracking via arc sensing, touch sensing, and TIG gap maintenance functions are pre-installed, making the system adaptable to a wide range of working conditions. Additionally, the integration of auxiliary axes and synchronized control maximizes the potential applications of robotic welding.
This process utilizes arc welding, a method that joins metals by generating an electric arc between the electrode and the base material. Three main welding functions are primarily used: arc sensing, touch sensing, and weaving motion.Arc Sensing (Arc Tracking): Tracks the weld seam centerline and adjusts height between workpiece and torch in real time using welding current data. Both unidirectional and bidirectional arc sensing are supported, the latter being required for weaving operations. Applicable to MIG/TIG welding.

● Arc Sensing Function for Weld Seam Tracking

Rainbow Robotics’ collaborative robots come equipped with seam-tracking capabilities through arc sensing. This feature enables the robot to automatically follow the weld seam while adjusting the height between the base material and the electrode in real time during the welding process. It also compensates for deviations caused by material distortion or inaccuracies in teaching, maintaining consistent weld quality by utilizing current feedback from the welding machine. Arc sensing is categorized into unidirectional and multidirectional modes, with the latter required when used in combination with weaving. This functionality supports a variety of welding methods, including MIG and TIG.

● Touch Sensing Function for Detecting Base Material

The touch sensing function is designed to enhance welding applications. It detects the movement of the base material and reflects its direction in the welding process. This allows the robot to fine-tune the position of the electrode relative to the joint or surface of the material, ensuring precise alignment for optimal weld quality.

● Various Weaving Profiles

Weaving motion plays a crucial role in welding processes. Rainbow Robotics’ collaborative robots feature a user interface that includes built-in capabilities for creating various weaving patterns and profiles. The system supports a wide range of shapes commonly required in welding sites, such as trapezoidal, triangular, sine wave, square wave, sawtooth, and circular patterns. Users can simply select a shape and parameters to implement weaving motions easily, eliminating the need for time-consuming manual programming.

Improved On-Site Efficiency Post-Deployment

Since adopting the system, HD Hyundai Samho has seen improvements in work speed and overall productivity, along with more consistent weld quality. While manual welding takes about 13 minutes per flat block and the robot takes around 15 minutes, robots can work continuously without breaks.

In a day, a robot can weld up to 50 steel plates, compared to 25 by a human welder — doubling daily output. Manual welding can lead to quality variations and potential rework, while robots provide high precision from the start, eliminating such inconsistencies.

Additionally, a collaborative robot monitoring system collects real-time data on work hours, peak times, welding quantity, and robot operation rates. This enables data-driven forecasting and deployment, leading to more efficient manpower and equipment management based on workload.

Setting a New Standard for Automation in Shipbuilding

This project proves the real-world applicability of portable collaborative robot systems in the demanding environments of the shipbuilding industry. It demonstrates how collaborative robots can provide the necessary flexibility and precision in even the most complex manufacturing processes. Rainbow Robotics remains committed to leading automation innovations across various industrial sectors.