Engineering Review: Double Pulse 6-Axis Collaborative Welder – Riyadh, Saudi Arabia

Field Report: Deployment of Double Pulse 6-Axis Collaborative Welder – Riyadh Industrial Area

This report details the technical deployment and performance evaluation of a Double Pulse 6-Axis Collaborative Welder at a mid-scale structural fabrication facility in Riyadh, Saudi Arabia. The primary objective was the transition from manual GMAW (Gas Metal Arc Welding) to a semi-autonomous workflow focused on heavy-duty carbon steel welding. As the manufacturing sector in KSA shifts toward localized production, the integration of Automated Welding systems is no longer optional for maintaining the tolerances required by high-spec infrastructure projects.

1. System Configuration and the 6-Axis Collaborative Welder Advantage

The core of the installation is a 6-Axis Collaborative Welder integrated with a high-amperage double pulse power source. Unlike traditional industrial robots that require extensive light curtains and physical fencing—consuming valuable floor space in a crowded Riyadh workshop—the collaborative nature of this system allows for a “human-in-the-loop” strategy.

1.1 Degrees of Freedom and Torch Accessibility

The 6-axis configuration is critical when dealing with complex geometries common in carbon steel structural nodes. In our specific application, we were welding H-beam stiffeners and circular hollow section (CHS) baseplates. The sixth axis allows for constant torch orientation relative to the weld pool, maintaining the optimal push angle (usually 10 to 15 degrees) even when transitioning through tight radii. This mechanical dexterity ensures that shielding gas coverage remains laminar, preventing the porosity often seen in 4-axis or 5-axis limited systems.

1.2 Safety and Proximity

The “Collaborative” aspect was tested rigorously on-site. Using force-torque sensors in each joint, the arm is programmed to stop upon contact with a technician. This allowed our lead welders to stand adjacent to the arc to monitor the melt pool in real-time, adjusting parameters via the tablet interface without halting the automated welding cycle. This proximity is vital during the initial “dial-in” phase of a new project.

2. Implementing Automated Welding in a High-Ambient Temperature Environment

Riyadh’s environmental conditions present unique challenges for automated welding hardware. During the commissioning phase, ambient temperatures in the workshop reached 44°C. This has a direct impact on the duty cycle of the power source and the thermal expansion of the carbon steel workpieces.

2.1 Thermal Compensation and Path Planning

One of the primary lessons learned was the necessity of “Touch Sensing” and “Thru-Arc Seam Tracking.” On long carbon steel welding runs, thermal distortion causes the joint to migrate. Our automated welding routine was programmed to perform a three-point touch sense at the start of every cycle to recalibrate the 6-Axis Collaborative Welder’s path. Without this, the weld bead would consistently deviate from the root, leading to lack of fusion on the side walls.

2.2 Duty Cycle Management

While the cobot arm is rated for 100% duty cycle, the liquid-cooled torch and the power source are the bottlenecks. We adjusted the automated welding logic to include a 60-second “cool down” path between assemblies, where the arm moves to a cleaning station to ream the nozzle. This prevents the contact tip from overheating, which is the leading cause of wire burn-back and “bird-nesting” in the wire feeder.

3. Technical Performance: Carbon Steel Welding and Double Pulse Dynamics

The project focused exclusively on Carbon Steel welding (Grade S355JR and ASTM A36). The shift to Double Pulse technology was driven by the need for TIG-like aesthetics with MIG-level productivity.

3.1 The Double Pulse Advantage

Double pulse GMAW functions by oscillating the wire feed speed and the current between two levels. In our Riyadh application, this was essential for out-of-position welds. The “high” pulse provides deep penetration into the carbon steel, while the “low” pulse allows the puddle to freeze slightly, preventing sagging in vertical-up (3G) positions.

We achieved a 25% reduction in total heat input compared to standard spray-transfer GMAW. This is critical for carbon steel welding because excessive heat grain coarsening in the Heat Affected Zone (HAZ) can lead to brittle failure under the seismic loads specified for Riyadh construction projects.

3.2 Spatter Reduction and Post-Weld Cleanup

A significant “hidden” cost in Saudi workshops is the manual labor required for spatter removal. By fine-tuning the 6-Axis Collaborative Welder’s waveform, we virtually eliminated spatter. The synergy between the automated welding software and the double pulse power source meant that the “pinch” effect of the droplet transfer was timed perfectly with the current dip. The result was a bead profile that required zero grinding, moving the part directly from the weld station to the sandblasting bay.

4. Synergy: Why the 6-Axis Cobot and Automated Welding Must Move Together

The term “Automated Welding” is often used loosely, but in this field deployment, it specifically refers to the integration of the 6-axis movement with the pulse-logic of the power source. They are not two separate entities; they are a single localized ecosystem.

4.1 Lead-Through Programming

One of the practical advantages we exploited in Riyadh was “Lead-Through” programming. A senior welder manually moves the 6-Axis Collaborative Welder arm along the desired path. The system records the coordinates. This “teaches” the automated welding system the nuances of the joint. In carbon steel welding, where fit-up can be slightly inconsistent due to thermal cutting tolerances, this manual “teaching” allows the operator to build in “weaves” that a standard CAD-to-Path software might miss.

4.2 Data Logging and Quality Assurance

Every centimeter of the carbon steel welding process was logged. In the event of a NDT (Non-Destructive Testing) failure—such as an ultrasonic indication—we could go back to the timestamp of the automated welding log and see exactly what the voltage, current, and gas flow were at that coordinate. This level of traceability is becoming a requirement for Saudi Aramco and NEOM-related sub-contracts.

5. Lessons Learned and Practical Recommendations

After three months of operation in the Riyadh facility, several “ground-truth” engineering insights have emerged regarding the 6-Axis Collaborative Welder and its role in carbon steel welding.

5.1 Shielding Gas Consistency

We initially experienced intermittent porosity. The lesson learned was that the high-velocity swamp coolers used in Riyadh workshops create significant drafts. Even a 6-Axis Collaborative Welder with perfect torch angles cannot compensate for a 15 km/h gust stripping the shielding gas. Recommendation: Use localized screens or increase gas flow from 15 L/min to 22 L/min when working in open-bay environments, despite the slight increase in consumable cost.

5.2 Wire Selection and Storage

Carbon steel welding wire is susceptible to surface oxidation in humid conditions, though Riyadh is generally dry. However, dust is the primary enemy. The automated welding wire conduit must be fully enclosed. We observed that dust accumulation on the wire was being carried into the liner, causing friction spikes that the cobot’s sensitive motors interpreted as a collision. We transitioned to a “Drum” feed system with a sealed “Dome” to ensure the wire remained pristine.

5.3 The Human Factor: Upskilling vs. Replacement

The most successful outcome was not the replacement of welders, but their evolution into “Robot Operators.” The 6-Axis Collaborative Welder handled the monotonous 1-meter straight runs on carbon steel plate, while the human welders focused on the complex tacking and the final quality inspections. This synergy increased the workshop’s total linear meterage of weld per shift by nearly 40%.

6. Conclusion

The deployment of the Double Pulse 6-Axis Collaborative Welder in Riyadh demonstrates that automated welding is the most effective solution for scaling carbon steel welding operations in the region. By leveraging the 6-axis freedom of the cobot, we solved the problem of complex geometry accessibility, while the double pulse technology ensured metallurgical integrity and aesthetic quality. For future deployments, the focus must remain on environmental shielding (dust/wind) and robust touch-sensing protocols to account for the thermal realities of the Saudi industrial landscape.

Report End.
Senior Welding Engineer – Riyadh Field Office