High-speed laser cladding technology, developed from traditional laser cladding, is an efficient surface engineering technique that significantly improves processing efficiency and reduces overall costs. However, in practical applications, controlling processing costs remains a crucial challenge. Since the cost of metal powder typically accounts for 80%–90% of the total cost of laser cladding, increasing powder utilization has become a key factor in promoting the large-scale application of high-speed laser cladding technology. This article systematically reviews the main factors affecting powder utilization in high-speed laser cladding and explores corresponding process optimization directions.

1. The Effect of Melt Pool Spot Size on Powder Utilization

In high-speed laser cladding, the size of the melt pool spot directly determines the effective area for powder capture and melting. If the spot size is too small, some powder will fail to enter the melt pool, resulting in waste. Conversely, while a larger spot size may improve powder reception per pass, it can lead to decreased coating flatness, increasing subsequent grinding and polishing work, thus reducing overall powder utilization. Therefore, appropriately matching the spot size with the process objectives is essential for improving overall powder utilization in high-speed laser cladding.

2. Powder Feeding Hole Structure and Powder Flow Characteristics

The diameter of the powder feeding hole in the cladding head directly impacts the concentration and stability of the powder flow. Smaller hole diameters lead to more concentrated powder beams but cause rapid dispersion in the air. Larger holes can cause the powder to spread beyond the laser action zone, leading to powder loss. The ideal high-speed laser cladding process should ensure that the powder spot diameter on the substrate surface is slightly smaller than or equal to the melt pool spot diameter to maximize powder utilization.

3. The Relationship Between Laser Power and Powder Melting State

Laser power is the core parameter that determines whether the powder can be fully melted. Under constant powder feeding and other process conditions, insufficient power results in incomplete powder melting and powder loss due to splattering. Increasing the power appropriately can improve the powder melting rate and bonding quality, thus enhancing powder utilization in high-speed laser cladding. However, excessive power can cause over-evaporation or melt pool instability, so it is crucial to find the optimal process window.

4. Balancing Powder Feeding Rate and Process Efficiency

The powder feeding rate affects both the thickness and forming efficiency of the cladding layer, as well as powder utilization. Under constant laser power, lower powder feeding rates result in more efficient use of each unit of powder. However, excessively low feeding rates can significantly reduce cladding efficiency, thereby negating the advantages of high-speed laser cladding. Therefore, it is important to optimize the powder feeding rate considering production rhythm and cost structure.

5. The Effect of Scanning Speed on Powder Behavior

High-speed laser cladding uses scanning speeds far higher than traditional laser cladding, which presents higher demands for powder particle movement and energy absorption. Increased speed enhances the kinetic energy of the powder particles, causing some to eject before they reach the melt pool. Additionally, high-speed motion shortens the powder’s residence time in the beam, weakening the melting effect. Therefore, while pursuing high speed, it is important to balance powder melting efficiency and utilization.

6. The Influence of Workpiece Size on Energy Transfer

The size and shape of the workpiece directly affect the absorption of laser energy and heat transfer. When conducting high-speed laser cladding on large or highly conductive substrates, rapid heat loss can lead to insufficient melt pool temperature, making it difficult to fully melt the powder, thus decreasing powder utilization. In such cases, increasing laser power or implementing preheating processes is often necessary to maintain the process stability and optimize powder utilization in high-speed laser cladding.

7. Powder Particle Size and Its Compatibility with the Cladding Process

The particle size of the powder determines its heat absorption rate and melting behavior. In high-speed laser cladding, the interaction time between the powder and the laser beam is extremely short, so selecting the appropriate powder particle size distribution is crucial. Larger particles are difficult to melt fully within the limited time, causing un-melted particles to be ejected, while smaller particles are more likely to be blown away by air currents or suffer from burn-off. Proper powder selection is key to achieving high-quality high-speed laser cladding and improving powder utilization.

8. Conclusion and Outlook

High-speed laser cladding, as an important development direction of laser cladding technology, is influenced by multiple process and equipment factors affecting powder utilization. From spot control and powder feeding parameters to powder characteristics and workpiece conditions, all factors need to be systematically considered and optimized. It is important to note that powder utilization should not only focus on direct losses during the cladding process but should also take into account material losses in subsequent machining stages. Therefore, “overall process utilization” should be the evaluation standard.

Looking ahead, with the continued application of process modeling, real-time monitoring, and closed-loop control, the powder utilization rate in high-speed laser cladding is expected to continue improving. This will drive broader and more cost-effective industrial applications of this technology in remanufacturing, surface engineering, and additive manufacturing.