Controlling Single-Layer Cladding Width in Laser Cladding Process

The single-layer Laser Cladding width in laser cladding is primarily determined by the coupled effects of laser parameters, powder feeding conditions, and scanning parameters. Laser power and spot size are core energy-related factors: higher laser power increases energy input, expanding the melting range of the substrate and powder to widen the cladding layer, while a larger spot size reduces energy density but broadens the melting area under constant power. Powder feeding rate also plays a critical role; excessive powder requires more energy for melting, reducing the effective energy acting on the substrate and narrowing the cladding width, whereas insufficient powder may lead to over-widening due to excessive substrate melting. Additionally, scanning speed affects energy accumulation per unit area-higher speeds shorten melting time and narrow the width, while lower speeds increase the melting range but risk excessive heat-affected zones. Material properties such as thermal conductivity and melting point further modulate the width by influencing heat dissipation and energy requirements for melting.

Achieving accurate control of single-Layer Cladding width relies on systematic parameter optimization and real-time feedback regulation. Parameter optimization, the foundational approach, involves determining the optimal combination of laser power, powder feeding rate, and scanning speed through experimental design or numerical simulation. Simulation tools (e.g., finite element analysis) can predict temperature fields and cladding geometries, reducing experimental costs and improving efficiency. Real-time feedback control is essential to counteract process disturbances (e.g., laser power fluctuations, uneven powder feeding). This strategy employs online monitoring devices (e.g., CCD cameras, laser sensors) to capture cladding width in real time, and adjusts key parameters dynamically-for instance, increasing scanning speed or decreasing laser power if the width exceeds the set value, or vice versa. Auxiliary measures such as substrate preheating (to stabilize heat distribution) and optimized shielding gas flow (to control molten pool stability) also enhance width uniformity.

Reliable detection methods are indispensable for verifying and refining width control effects, with offline and online techniques complementing each other. Offline detection methods, such as optical microscope observation and coordinate measuring machine (CMM) measurement, offer high accuracy by analyzing cross-sectional samples or 3D surface data, making them suitable for post-process quality inspection and parameter calibration. Online detection, critical for real-time feedback, primarily uses image processing technology-high-speed cameras capture molten pool or solidified Laser Cladding layer images, and edge detection algorithms (e.g., Canny operator) extract width information. To overcome harsh process environments (high temperature, smoke, strong light), online systems often integrate protective measures (e.g., filters, dust removal devices) and multi-sensor fusion (combining image, laser, and ultrasonic sensors) to improve detection reliability. These detection methods provide data support for parameter optimization and feedback control, forming a closed-loop system for stable width control.