1. Working Principle
A laser marking machine uses a laser beam to create permanent marks on the surface of various materials. The marking effect is mainly achieved through two methods.
Thermal processing: A high-energy-density laser beam irradiates the surface of the material. The surface absorbs the laser energy and generates a thermal excitation process in the irradiated area, causing the material temperature to rise. This leads to changes such as phase transformation, melting, ablation, and evaporation, leaving a visible mark on the surface.
Cold processing: High-energy ultraviolet photons break the chemical bonds in the raw material, especially organic materials, or in the surrounding medium. This causes non-thermal damage to the material. Unlike thermal processing, cold processing does not produce heat-affected zones. Instead, it removes material by breaking chemical bonds, so the inner layers and surrounding areas of the processed surface are not subjected to heating or thermal deformation.
2. Structure of the Laser Marking Machine
A laser marking machine mainly consists of the following components.
Laser Power Supply
The laser power supply provides power to the fiber laser. Its input voltage is normally AC 220 V. The power supply is installed inside the control box of the laser marking machine.
Fiber Laser
The fiber laser marking machine uses a pulsed fiber laser with good output beam quality and long service life. The laser is mounted inside the machine body.
Galvanometer Scanning System
The galvanometer scanning system consists of an optical scanner and a servo control unit. The optical scanner uses an AC servo motor with a moving-magnet deflection mode. It offers a large scanning angle, high peak torque, large load inertia, small electromechanical time constant, fast operation speed, and stable performance.
The optical scanner is divided into an X-direction scanning system and a Y-direction scanning system. A laser reflecting mirror is fixed on the shaft of each servo motor. The computer sends digital signals to control the scanning path.
Focusing System
The focusing system focuses the parallel laser beam to a single point. It usually uses an f-θ lens. Different f-θ lenses have different focal lengths, which affect the marking effect and marking range.
The fiber laser marking machine is equipped with a high-performance focusing system. The standard lens focal length is f = 160 mm, and the effective scanning range is Φ110 mm. Users can select different lens models according to actual needs.
Computer Control System
The computer control system is the core of control and command for the laser marking machine. It coordinates the acousto-optic modulation system and the galvanometer scanning system to complete laser marking on workpieces.
The computer control system mainly includes the main chassis, motherboard, CPU, hard disk, memory, D/A card, optical drive, display, keyboard, and mouse.
For non-standard mechanical parts used in laser marking systems, such as optical mounting brackets, galvanometer motor seats, and focusing lens adjustment holders, Hansheng Automation provides custom machining based on customer drawings or samples, including single-piece and small-batch orders.
