As laser manufacturing technology continues to evolve, rechargement laser has emerged as an advanced surface engineering technique with significant advantages in remanufacturing, surface strengthening, and component repair. Powder feeding methods play a critical role in determining the effectiveness of rechargement laser, directly impacting the quality of the cladding layer and the process efficiency. The center-feed laser cladding technology, developed as a new powder feeding method based on traditional off-axis and coaxial powder feeding, is especially suited for high-speed rechargement laser applications. This method fully utilizes the advantages of rechargement laser in surface flatness, processing efficiency, and powder utilization.

What is Center Feed Laser Cladding Technology?

Center feed technology, often referred to as “light-package powder” technology, is characterized by a single powder channel in the center of the cladding head. The laser beam is distributed in a ring shape or in multiple beams surrounding the powder flow. During the rechargement laser process, the metal powder flows from the central channel under the action of aerodynamics and gravity. The surrounding laser beams converge with the powder on the workpiece surface. The powder in the center is heated by the laser energy to a molten or semi-molten state and then falls into the molten pool, forming a dense and smooth metallurgical bond layer.

Now, let’s analyze the differences between center-feed rechargement laser technology and other powder feeding methods across several key dimensions.

1. Significant Improvement in Powder Utilization, Up to 90%

Compared to traditional coaxial pneumatic powder feeding methods, center-feed rechargement laser uses a single powder stream design, preventing scattering losses caused by multiple powder streams colliding. When performing vertical laser cladding, lower air pressure is used for powder feeding, which not only extends the contact time between the powder and the laser for better melting but also reduces the rebound and spattering caused by the powder colliding with the substrate. Practical applications show that this technology can improve powder utilization up to 90%, which is crucial in reducing the consumption of high-cost metals during rechargement laser.

2. More Stable Optical System, Supporting Long-Term Continuous Processing

In coaxial and off-axis powder feeding methods, the laser beam directly impacts the molten pool, and the high reflectivity and sustained thermal radiation of the pool can interfere with the optical system, affecting the stability of long-term processing. Center-feed rechargement laser heads, however, output the laser beam at a specific tilt angle, preventing the beam from directly reflecting back to optical components through the molten pool, effectively isolating the interference from thermal radiation and metal splashing. Therefore, this technology is particularly suitable for rechargement laser tasks that require continuous light output for extended periods, significantly enhancing equipment stability and lifespan.

3. High Cladding Efficiency, Suitable for High-Quality Thin Layers

In typical rechargement laser applications, center-feed technology achieves high cladding efficiency due to the high coupling efficiency between the powder and the laser energy. It can achieve a cladding efficiency of 0.7–1.2 m²/h (when the cladding layer thickness is 0.5–0.7mm). Additionally, high-speed rechargement laser results in a very short molten pool dwell time, which minimizes the dilution of the cladding layer and ensures that the substrate’s properties remain unaffected. The cladding layer produced by this technology also features excellent surface roughness, good crack resistance, and minimal thermal deformation of the workpiece, making it ideal for surface protective coatings on new components.

4. Comprehensive Comparison of Center Feed vs. Coaxial Powder Feeding

Compared to traditional coaxial pneumatic powder feeding methods, center-feed rechargement laser offers advantages in powder flow shape, air pressure requirements, and energy utilization. The single powder stream structure effectively prevents the powder from interfering with itself. Low air pressure and slow powder feeding enhance the laser’s heating effect on the powder, while also suppressing powder rebound and spattering. Actual rechargement laser cases show that center-feed processing results in gentle sparks with minimal spattering, improving surface quality and enhancing process repeatability.

Summary and Outlook

Off-axis and coaxial powder feeding methods have been widely used in the development of rechargement laser technologies, but their applications are limited due to issues such as powder utilization and optical system stability. Center-feed rechargement laser technology effectively addresses these shortcomings, showcasing several technical advantages. With the deep integration of high-speed rechargement laser and center-feed powder feeding, we believe that “high-speed rechargement laser + center-feed” will become the mainstream direction in the future of rechargement laser, playing an increasingly important role in high-end manufacturing and remanufacturing markets.