Engineering Review: 3000W 6-Axis Collaborative Welder – Curitiba, Brazil

Field Engineering Report: Integration of 3000W 6-Axis Collaborative Welder in Curitiba Industrial District

1. Project Overview and Site Conditions

This report details the commissioning and operational performance of a 3000W 6-Axis Collaborative Welder at a Tier-1 automotive tooling facility in Curitiba, Brazil. The primary objective was to transition from manual GTAW (TIG) processes to Automated Welding for high-precision Tool Steel welding applications, specifically focusing on the repair and surfacing of injection molds and stamping dies.

Curitiba’s industrial climate presents specific challenges, notably high ambient humidity which can impact shielding gas purity and wire surface oxidation. During the initial setup, we identified a requirement for enhanced gas filtration and specialized storage for filler metals to prevent porosity—a critical failure point when dealing with high-carbon tool steels. The system deployment utilized a 3000W fiber laser source integrated with a high-degree-of-freedom robotic arm, providing the necessary power density for deep penetration while maintaining the agility required for complex geometries.

2. The Synergy of 6-Axis Collaborative Welder and Automated Welding

The integration of a 6-Axis Collaborative Welder into the production floor represents a fundamental shift in how Automated Welding is perceived in the Brazilian market. Traditional industrial robots require extensive safety fencing and rigid programming, making them unsuitable for the “one-off” nature of tool and die repair. However, the collaborative nature of this 6-axis system allows engineers to work alongside the machine, using lead-through programming to define paths on irregular surfaces.

Kinematic Flexibility and Torch Orientation

In the context of Automated Welding, the “6-Axis” component is not a luxury; it is a technical necessity. When surfacing a complex P20 or H13 tool steel mold, the torch must maintain a consistent perpendicularity to the workpiece or a specific drag angle to manage the weld pool effectively. The 6-axis kinematics allow the cobot to reach into deep cavities of a mold—areas where a 3 or 4-axis linear system would inevitably encounter a mechanical singularity or collision. This flexibility ensures that the 3000W energy delivery remains constant, preventing undercuts or lack of fusion at the edges of the tool.

Collaborative Logic in Tooling Repairs

The synergy here lies in the “Human-in-the-loop” strategy. The senior welder in the Curitiba shop identifies the wear zones on the tool steel, manually guides the 6-Axis Collaborative Welder to define the start and end points, and then allows the automation software to calculate the weave pattern and travel speed. This removes the manual fatigue associated with maintaining a 0.5mm arc gap over a 4-hour shift, which is common in Tool Steel welding.

3. Technical Deep-Dive: Tool Steel Welding Parameters

Tool Steel welding is notoriously difficult due to the high carbon and alloy content (Chromium, Molybdenum, Vanadium), which increases hardenability and the risk of Martensitic cracking. Our implementation in Curitiba focused on two specific grades: H13 (Hot Work) and D2 (Cold Work).

Thermal Management and Power Modulation

Using the 3000W power source, we moved away from constant current delivery to pulsed modulation. This is where Automated Welding proves its superiority. By synchronizing the laser pulse with the 6-axis movement, we achieved a controlled Heat Affected Zone (HAZ). In Tool Steel welding, an oversized HAZ leads to a “soft spot” or subsequent cracking during heat treatment. The cobot’s ability to maintain a precise travel speed of 4.5 mm/s ensured that the energy input per linear millimeter was kept within the strict ±5% tolerance required for H13 stability.

The Preheating Requirement

A lesson learned during the first week in Curitiba was the necessity of integrating an induction preheating station with the 6-Axis Collaborative Welder. Even with 3000W of power, welding tool steel at an ambient temperature of 18°C led to hydrogen-induced cracking (HIC). We established a protocol where the automated system would only engage once the substrate reached 350°C. The cobot’s sensors were used to verify the surface temperature before initiating the Automated Welding sequence, ensuring a metallurgical bond rather than a superficial deposit.

4. Lessons Learned from the Curitiba Installation

Lesson 1: Redundancy in Path Planning

One frequent issue encountered was the “dead zone” in the arm’s reach when dealing with 500kg automotive dies. While a 6-Axis Collaborative Welder is agile, its reach is finite. We learned to position the die on a secondary rotary axis (effectively creating a 7-axis system). This synergy between the cobot and the workpiece positioner is essential for Automated Welding of large-scale tool steel components to avoid reaching the limits of the arm’s joints, which causes “jerky” motion and inconsistent bead appearance.

Lesson 2: Shielding Gas Dynamics

In the Curitiba workshop, cross-drafts from the ventilation system significantly impacted the gas lens performance. In Tool Steel welding, even minor oxidation can ruin a mold’s mirror finish. We switched to a high-flow gas shroud specifically designed for collaborative arms. Because the 6-Axis Collaborative Welder moves at angles a human wrist cannot sustain, the gas shroud must be designed to provide 360-degree coverage regardless of torch orientation.

Lesson 3: Software Abstraction for Local Operators

The transition to Automated Welding succeeded only because we abstracted the complex G-code into a visual interface. The Brazilian operators, while highly skilled in manual welding, initially struggled with the coordinate systems. By using the cobot’s “teach pendant” to simplify Tool Steel welding paths into “Start,” “Way-point,” and “End,” we reduced setup time by 40% over the first month.

5. Impact on Productivity and Metallurgical Quality

The deployment of the 3000W system has yielded a 65% reduction in post-weld machining time. Because the Automated Welding process deposits a much “nearer-to-net” shape than manual welding, the subsequent CNC grinding of the tool steel dies is significantly faster. Furthermore, the 6-Axis Collaborative Welder provided a consistency in bead overlap (set at 50% for this project) that is physically impossible to achieve manually.

From a metallurgical standpoint, the rapid cooling rates associated with the 3000W fiber source, when controlled by the precise motion of the 6-axis arm, resulted in a finer grain structure in the weld metal. This is a critical advantage for Tool Steel welding, as it improves the wear resistance of the repaired tool during high-volume production runs on the stamping line.

6. Conclusion and Future Scaling

The Curitiba project confirms that the 3000W 6-Axis Collaborative Welder is the optimal tool for high-precision Automated Welding in the tool and die sector. The key to success was not just the hardware, but the meticulous application of thermal controls and the strategic use of 6-axis motion to overcome complex part geometries. For future deployments, we recommend a standardized inclusion of an integrated induction heating unit and a localized dehumidification system for the wire feed unit to ensure consistent results in the humid Brazilian South.

Final Specification Summary:

• Power: 3000W Continuous Wave (Modulated)
• Motion: 6-Axis Collaborative (1300mm reach)
• Substrate: H13, D2, P20 Tool Steels
• Process: Laser-Wire Hybrid (Automated)
• Location: Curitiba, PR – Brazil