Engineering Review: High-speed MAG 6-Axis Collaborative Welder – Abu Dhabi, UAE

Field Performance Report: Integration of 6-Axis Collaborative Welder in Abu Dhabi

This report outlines the technical deployment and operational assessment of High-Speed MAG (Metal Active Gas) 6-axis collaborative welding systems within a high-capacity structural steel facility in the Industrial City of Abu Dhabi (ICAD). The objective was to transition specific high-volume carbon steel welding sequences from manual labor to Automated Welding to mitigate the impact of the regional climate on welder fatigue and to standardize joint quality.

The deployment focused on a specific 6-axis collaborative welder unit integrated with a high-speed MAG power source. Unlike traditional industrial robots, the cobot was selected for its small footprint and the ability to work alongside human fitters without expansive safety caging, which is a critical space-saving factor in the workshop’s current configuration.

The Synergy of Automated Welding and 6-Axis Kinematics

The transition to automated welding in the Abu Dhabi sector is often hindered by the complexity of structural geometries. Traditional 3-axis systems are insufficient for the non-linear seams found in our current carbon steel contracts. The 6-axis collaborative welder provides the necessary degrees of freedom (DOF) to maintain optimal torch angles—specifically the work angle and travel angle—across complex intersections, such as pipe-to-plate saddle welds and gusset reinforcements.

In this field application, the synergy between the cobot and the MAG process allowed for “lead-through” programming. Our senior welders, who are not robotic programmers, were able to physically move the 6-axis arm to define the weld path. This effectively transferred “tribal knowledge” regarding torch manipulation into a digital, repeatable program. The automated system then executed these paths with a consistency that manual welding cannot replicate over a 10-hour shift, particularly when ambient temperatures exceed 40°C.

Technical Parameters for Carbon Steel Welding

The primary material handled during this deployment was ASTM A36 and API 5L Grade B carbon steel, ranging from 6mm to 15mm in thickness. To maximize the efficiency of the 6-axis collaborative welder, we utilized a Metal Active Gas (MAG) process with a 1.2mm ER70S-6 solid wire and an 80/20 Argon/CO2 shielding gas mix.

Weld Procedure Specification (WPS) Calibration

To achieve high-speed results without sacrificing penetration, the following parameters were established for horizontal-vertical (PB) fillet welds:

• Wire Feed Speed: 10.5 m/min
• Voltage: 28.5V – 30V
• Travel Speed: 450 mm/min to 600 mm/min
• Gas Flow: 18 L/min (increased due to local workshop cross-drafts)

In carbon steel welding, heat input management is vital to avoid excessive grain growth in the Heat Affected Zone (HAZ). The automated welding controller monitored the energy input (kJ/mm) in real-time. By maintaining a constant travel speed through the 6-axis interpolation, we reduced the HAZ width by 15% compared to manual samples, resulting in superior Charpy V-Notch toughness results during the PQR (Procedure Qualification Record) phase.

Abu Dhabi Environmental Challenges and Mitigation

The environmental conditions in Abu Dhabi present unique stressors for any 6-axis collaborative welder. High humidity and ambient temperatures reaching 48°C in the summer months can lead to significant equipment derating and metallurgical defects.

Thermal Management of the Power Source

Most automated power sources are rated for a 100% duty cycle at 25°C or 40°C. In the ICAD workshop, we observed the thermal protection circuits tripping mid-weld during the afternoon shift. We implemented a dedicated closed-loop water-cooling unit for the MAG torch and added an external HVAC forced-air cooling system for the power source cabinet. This is a non-negotiable requirement for high-speed automated welding in the UAE.

Shielding Gas Integrity

Abu Dhabi’s coastal humidity can introduce moisture into the shielding gas lines, leading to hydrogen-induced cracking or porosity in carbon steel welding. We installed point-of-use inline desiccant dryers and switched from individual cylinders to a centralized bulk gas system with high-purity piping. This eliminated the intermittent porosity issues we initially faced during the 07:00 to 10:00 humidity peaks.

Performance Metrics: Manual vs. 6-Axis Collaborative Welder

The shift to the 6-axis collaborative welder was evaluated based on deposition rate and “Arc-on” time. Manual welders in the facility typically averaged an arc-on time of 25-30% due to the need for frequent breaks and repositioning. The automated welding station achieved an arc-on time of 75%.

Quality Control and NDT Results

Over a batch of 200 carbon steel structural nodes:

• Manual Repair Rate: 8.4% (mostly slag inclusions and undersized fillets)
• Cobot Repair Rate: 0.5% (limited to start/stop craters during initial setup)

Visual inspection (VT) showed a level of ripple consistency that reduced the need for post-weld grinding by 60%. Ultrasonic Testing (UT) confirmed that the 6-axis motion maintained a deep, consistent root penetration that is often missed in manual overhead or difficult-access positions.

Lessons Learned and Technical Recommendations

After six months of operation in the Abu Dhabi field site, several critical lessons have been identified for future automated welding rollouts involving carbon steel.

1. Tolerance Sensitivity in Automated Welding

While the 6-axis collaborative welder is highly repeatable, it is “blind” unless equipped with expensive laser-seam tracking. We learned that the upstream cutting and fitting processes must be tightened. Manual welders can compensate for a 2mm gap variation; the cobot cannot. We moved to CNC plasma cutting for all carbon steel welding preparations to ensure gap consistency within ±0.5mm.

2. Collaborative Safety vs. Productivity

The “collaborative” nature of the robot means it stops upon contact with a human. In a busy Abu Dhabi workshop, accidental bumps by fitters led to frequent “Emergency Stop” events, which ruined the weld bead continuity. We implemented “soft zones” using floor markings and light curtains. This maintained the “no-cage” benefit while reducing nuisance trips during the automated welding cycle.

3. Software Offsets for Thermal Expansion

Large carbon steel assemblies (over 3 meters) undergo significant thermal expansion during high-speed MAG welding. We observed the weld path drifting by up to 3mm by the end of a long seam. We programmed intermediate “cool-down” steps and used the 6-axis controller’s software to apply a linear offset to the path to compensate for the metal’s growth as it absorbs heat.

4. Maintenance of the 6-Axis Kinematics

The fine dust and sand typical of the UAE environment act as an abrasive on the cobot’s joints. We implemented a weekly “joint-cleaning” protocol using low-pressure compressed air and checked the encoder seals for ingress. Failure to do so leads to “joint jitter,” which manifests as micro-oscillations in the weld bead, compromising the fatigue life of the carbon steel joint.

Final Assessment

The deployment of the 6-axis collaborative welder for carbon steel welding in Abu Dhabi is a technical success, provided the environmental factors are managed. The automated welding process has effectively doubled the output of the structural line while significantly lowering the NDT failure rate. The key takeaway for senior engineering is that the technology is not “plug-and-play”; it requires a rigorous adjustment of upstream tolerances and a robust thermal management strategy to survive the regional climate.

Future phases will investigate the integration of “Through-Arc Seam Tracking” (TAST) to allow the 6-axis collaborative welder to autonomously adjust to fit-up variations, further reducing the reliance on high-precision tacking.

Report Prepared By:
Senior Welding Engineer, Abu Dhabi Operations
Date: October 2023