CHEC deploys custom welding robot for Saudi prefab project

China Harbour Engineering Company (CHEC) is constructing more than 5,000 villas and supporting facilities for the Sedra Phases 3-5 and East Riyadh projects in Saudi Arabia using fully prefabricated construction. Embedded-part welding is critical to structural safety, with manual welding producing inconsistent quality that cannot meet mass-production demands.

In December 2024, the project team began developing a custom welding robot. Curved welds formed by threaded rebar against steel plates lack a uniform pattern, and commercial vision systems designed for flat, regular workpieces fail because of rebar reflections and surface deformation. Through iterative algorithm optimization, the team introduced multi-dimensional feature extraction to eliminate reflection interference and developed an adjustable calibration module to correct clamping deviations in real time, achieving 1-millimeter weld detection accuracy. The hand-eye coordinated system integrates modular quick-change fixtures, intelligent path planning, and precision welding, matching optimal paths and parameters for different embedded parts.

The robot entered service in June 2025, but Riyadh's extreme heat and strong sunlight caused vision errors and equipment overheating. The team added thermal shielding to the cameras, upgraded image algorithms with glare filtering and automatic temperature correction, and improved cooling circuits and auxiliary fans to ensure accurate recognition and stable operation in high-temperature conditions.

The robot achieves a 99.5 percent weld pass rate and 50 pieces per hour, an 80 percent productivity gain over manual welding. The resulting technology – automated identification and welding of multi-spec embedded parts with digital control – has been granted a national invention patent, providing a replicable solution for automated embedded-part welding.

The site of the Sedra Phases 3-5 and East Riyadh projects in Saudi Arabia. [Photo provided to chinadaily.com.cn]

A custom welding robot. [Photo provided to chinadaily.com.cn]