Optimising Trencher blade lifecycles: High-precision hardfacing via Wire-Laser Deposition

Optimising Trencher Blade Lifecycles: High-Precision Hardfacing via Wire-Laser Deposition

In the utility and construction sectors, equipment uptime dictates project margins. Trenchers and wheel saws, specifically designed to excavate narrow channels for cabling and piping, operate in some of the most hostile environments imaginable. The cutting wheel acts as the primary engagement point, subjected to continuous, brutal impact from rock, abrasive soil types, and subterranean debris.

Consequently, the segments making up these wheels are high-consumption consumables.

The traditional supply chain model relies on buying expensive spare parts and accepting significant downtime during replacements. However, the industry is shifting toward advanced repair protocols that not only restore these components but improve their baseline metallurgy for extended service life.

1. Abrasion mechanics and component degradation

The specific component analysed in this case is a trencher segment, a critical part of the cutting wheel assembly. Under standard operation, the segment faces severe abrasion that rapidly erodes the cutting geometry.

Once the protective surface is compromised, the base metal wears away exponentially, leading to catastrophic failure or ineffective trenching. The operational reality is that standard steel segments cannot withstand prolonged exposure to abrasive geological formations without significant degradation. Operators are forced to balance the high cost of frequent replacements against the productivity losses of operating with worn equipment.

A solution that reinforces the part against extreme wear while maintaining structural integrity is essential.

2. Metallurgical control in hardfacing

Applying a wear-resistant layer, known as hardfacing, is not a new concept, but doing so with precision presents specific metallurgical challenges. Traditional arc welding methods often result in high heat input, which causes excessive dilution.

Dilution occurs when the base material melts into the coating, effectively watering down the hardfacing material and reducing its wear-resistant properties. Furthermore, inconsistent thermal gradients in traditional processes can lead to spalling or cracking, rendering the repair useless.

The engineering objective for this trencher segment was to apply a dense, uniform coating of cast tungsten carbides in a nickel-based matrix (NICARBW-LD). The target was to achieve a metallurgical bond with low dilution (preserving the carbide's properties) and zero cracking, a difficult balance to strike on complex geometries.

3. How is Meltio used for cladding applications?

In collaboration with Welding Alloys, Meltio deployed a wire-laser metal 3D printing approach to carry out a two-layer hardfacing operation. The process used the Meltio Engine Robot Integration, which allows for the precise 6-axis deposition required for the curved geometry of the trencher segment.

The execution followed a rigorous five-step cladding protocol to ensure repeatability:

1. Part evaluation and preparation. The component was inspected for surface oxidation. Using the Meltio system's multi-laser capability, a laser cleaning pass was performed to prepare the substrate, eliminating the need for aggressive mechanical grinding in some areas.
2. Digital reconstruction. As the damaged area required precise machining references, the part was scanned. Reverse engineering allowed the team to recreate the part digitally, generating an exact mesh for toolpath generation.
3. Reference alignment. To address the lack of standard centring protocols in robotics, the team established three specific reference points on the fixture. This triangulation served as the guide for locating the part within the robot's coordinate system.
4. Calibration. Using the 3-Point Calibration Method, the exact coordinates were fed into Meltio Space, the slicing software. This ensured the digital toolpath aligned perfectly with the physical part, guaranteeing the hardfacing material was deposited exactly where required.
5. Deposition. The robot executed the printing process using NICARBW-LD wire. The process was shielded by 100% argon gas to prevent oxidation during melt pool formation.

4. Metallurgical integrity and operational efficiency

The application of Laser Metal Deposition (LMD) yielded quantifiable technical improvements over traditional hardfacing methods.

• Controlled dilution. The process achieved an average dilution rate of approximately 5% to 10%. This low dilution ensures that the nickel matrix and tungsten carbides retain their intended hardness and abrasion resistance without being compromised by the iron from the substrate.
• Structural integrity. Post-process analysis revealed excellent adhesion with no observed spalling or cracking, a critical factor for parts subjected to high-impact shocks.
• Material efficiency. Unlike subtractive manufacturing or messy spray coatings, the wire-laser process resulted in zero material waste. The wire is fed directly into the melt pool, ensuring 100% utilisation of the expensive high-performance alloy.
• Enhanced performance. The resulting component is not merely repaired; it is reinforced. The tungsten carbide overlay provides extreme resistance to abrasion, significantly extending the mean time between failures (MTBF) compared to the original OEM specification.

At a glance

• System: Meltio Engine for Robot integration
• Sector: Civil engineering
• Material: NICARBW-LD
• Partner: Welding Alloys

5. Conclusion

This case study demonstrates that wire-laser metal 3D printing is a viable, industrial-grade solution for heavy equipment maintenance. By combining the agility of robotic integration with the precision of the Meltio Engine, civil engineering firms can move beyond simple repairs.

They can implement a strategy of component enhancement, where parts return to the field stronger and more durable than when they left the factory. The collaboration with Welding Alloys proves that integrating advanced materials like NICARBW-LD with precise laser deposition sets a new standard for hardfacing performance in the field.

This case study was originally published by Meltio as Optimizing Trencher blade lifecycles: High-precision hardfacing via Wire-Laser Deposition, written by Rubén de las Heras, in collaboration with Welding Alloys. Reproduced here with credit to Meltio.