What is a laser scan head?

A laser scan head is a sophisticated device that steers a laser beam with incredible speed and precision. In any advanced laser-based manufacturing system, the scan head is a critical component that takes a static laser beam and turns it into a dynamic, highly versatile processing tool. It's the precision laser material processing technology that enables the rapid, intricate movements required for applications like high-speed marking, micro-drilling and complex pattern cutting.

While traditional motion systems use large stages to move a workpiece under a fixed beam, a scan head moves the beam itself using small, agile mirrors. This allows for much higher accelerations and velocities over a specific area, known as the field of view, making it essential for maximizing throughput and creating fine features.

What is a galvo system?

A galvo system, often called a galvo scanner, is the most common type of laser scan head used in industrial applications. The name "galvo" is short for galvanometer, which is a type of high-speed, high-accuracy electric motor. A galvo system uses these motors to rapidly pivot mirrors, which in turn deflect and steer the laser beam.

This system is the engine behind the scan head's agility. By precisely controlling the rotation of the mirrors, a galvo system can position a laser spot anywhere within its processing field almost instantaneously. This capability is fundamental to any laser process that requires quick jumps between locations or the smooth tracing of complex paths.

What is galvo head?

A "galvo head" is simply another term for a galvanometer-based laser scan head. It refers to the complete assembly, which typically includes:

• Galvanometer Motors: Two high-speed motors that drive the mirrors. One motor controls X-axis motion, and the other controls Y-axis motion.

• Mirrors: Small, lightweight, highly reflective mirrors mounted to the motor shafts. Their low inertia allows them to be accelerated and repositioned very quickly.
• Encoder Feedback: High-resolution position sensors (encoders) that constantly track the exact angle of the mirrors.
• Control Electronics: The drive electronics and servo controller that interpret command signals and provide the necessary power and control logic to the motors.
• Focusing Optics: An F-theta lens is typically placed after the mirrors to focus the steered beam onto the workpiece and ensure the spot remains in focus across the entire processing field.

How does a galvo head work?

A galvo head works on a principle of closed-loop control. A command signal, representing a desired X-Y coordinate, is sent to the scan head's controller. The controller then sends a current to the galvanometer motors, causing them to rotate the mirrors toward the target angles.

Simultaneously, the high-resolution encoders on the motors provide real-time feedback on the mirrors' actual angular position. The controller constantly compares this actual position to the commanded position and adjusts the motor current to correct for any difference or "error." This continuous feedback loop happens thousands of times per second, ensuring the mirrors follow the commanded path with extremely high fidelity and accuracy. This closed-loop operation allows a galvo head to achieve both its remarkable speed and its micron-level precision. 

What is a galvo scanner used for?

So, what is a laser scan head used for in practice? A galvo scanner is employed in any laser application where high speed and intricate detail are required within a localized area. Its ability to quickly jump the beam or trace complex patterns makes it indispensable for:

• Laser Marking: Creating serial numbers, barcodes and logos on products at high speed. This is one of the most common uses.

• Laser Engraving: Creating detailed artistic patterns or deep marks.

• Micro-Drilling: Rapidly drilling thousands of tiny holes in materials like printed circuit boards or medical catheters.

• Scribing: Creating fine lines on brittle materials like silicon or sapphire for clean, controlled breaking.

• Laser Cutting: Cutting intricate shapes in thin materials such as medical stents, flexible circuits and textiles.

• Additive Manufacturing (3D Printing): Quickly scanning the cross-section of a part in a powder bed to selectively melt or sinter the material.

Choosing the best galvo laser scan heads for a specific task involves evaluating factors like aperture size, mirror coatings, thermal stability and control features to ensure optimal performance.

Talk to Aerotech about integrating the best scan head and motion control solutions into your laser processing systems.