A galvo head is a critical component in precision laser scanning systems and other optical applications where accurate and rapid beam steering is required. It consists primarily of a galvanometer motor with a mounted mirror, designed to control the angle of reflection of a laser beam or light with high precision and speed. The galvo head enables dynamic beam positioning, allowing lasers or other light sources to be directed accurately over a target surface or through an optical path.
What Is a Galvo Head?
The galvo head is essentially the mechanical and optical assembly that houses the galvanometer motor and mirror system. The galvanometer motor converts electrical control signals into precise angular movements. Mounted on the motor shaft is a lightweight mirror, which reflects the incoming laser or light beam. By controlling the mirror’s angle, the galvo head directs the beam’s path with extreme accuracy.
Typically, galvo heads come in single-axis or dual-axis configurations. A single-axis galvo head controls beam movement in one direction (horizontal or vertical), while a dual-axis galvo head has two galvo motors arranged orthogonally to steer the beam in two dimensions (X and Y axes), enabling scanning over a plane.
How Does a Galvo Head Work?
Inside the galvo head, the galvanometer consists of a coil suspended in a magnetic field. When an electrical current flows through the coil, magnetic forces cause it to rotate. The mirror attached to this coil moves correspondingly, altering the reflected beam’s angle.
The galvo head operates in a closed-loop control system. A position sensor (optical encoder or Hall sensor) continuously monitors the mirror’s position, sending feedback signals to the controller. This feedback ensures the mirror moves precisely to the commanded angle, compensating for inertia or external disturbances and maintaining accuracy even at high speeds.
The key advantages of galvo heads include very low inertia due to the small mirror and coil assembly, which allows for rapid acceleration and deceleration, and highly repeatable, stable positioning.
Applications of Galvo Heads
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Laser Marking and Engraving:
Galvo heads are widely used in laser marking machines where the laser beam must be quickly and accurately directed to create text, logos, or complex patterns on materials ranging from metals to plastics. -
Laser Cutting and Welding:
In industrial manufacturing, galvo heads steer the laser for precise cutting or welding paths, enabling complex shapes and fine details with high throughput. -
3D Printing and Additive Manufacturing:
Galvo heads are employed in systems like stereolithography to scan curing lasers across resin surfaces, forming 3D structures layer by layer with precision. -
Medical and Scientific Instrumentation:
Laser galvo heads are used in confocal microscopes and laser scanning systems for imaging, as well as in laser therapy equipment where precise beam placement is critical. -
Laser Shows and Displays:
Entertainment and visual display industries use galvo heads to steer laser beams rapidly, creating dynamic images, animations, and effects during performances.
Advantages and Limitations
Galvo heads provide high scanning speeds and exceptional angular resolution, making them ideal for applications requiring fast, accurate beam positioning. Their compact size facilitates integration into various optical systems.
However, galvo heads usually have a limited angular range—often around ±20 to 30 degrees—which restricts the maximum scanning area without additional optics. Maintaining the mirror’s cleanliness and preventing mechanical wear are important for sustained performance.
Conclusion
A galvo head is a fundamental building block for modern laser scanning and beam steering systems. By converting electrical signals into fast, precise angular movements of a mirror, it enables laser beams and light to be directed exactly where needed with great speed and accuracy. From industrial manufacturing to scientific research and entertainment, the galvo head plays a vital role in expanding the capabilities and applications of laser technology.