What is the Oscillation Principle of Galvanometer in Laser Welding?

What is the Oscillation Principle of Galvanometer in Laser Welding?

Galvanometer laser soldering is an exceptionally efficient welding technique that utilizes mirror oscillation to scan the target soldering area. Songsheng Optoelectronics will now explain the oscillation principles of galvanometers in laser soldering—let’s dive in!

Basic Structure and Function

The laser welding galvanometer system mainly consists of a galvanometer motor, reflecting mirrors, and a drive controller. The galvanometer motor serves as the core component, capable of precisely driving the reflecting mirrors for high-speed oscillation. Typically, there are two reflecting mirrors for the X-axis and Y-axis directions, which respectively control the laser's scanning path horizontally and vertically. The drive controller is responsible for sending signals to regulate the motion of the galvanometer motor.

The primary purpose of the galvanometer oscillation is to alter the laser's irradiation position, enabling flexible scanning of the welding area. In laser welding, the oscillation of the galvanometer allows for the welding of complex-shaped seams, such as circular, arc-shaped, or irregular weld paths.

Schematic Diagram of Galvanometer Scanning Welding Principle

Implementation of Oscillation Principle in Two-Dimensional Plane (Taking X-Y Plane as Example)

X-Axis Oscillation Principle:
The X-axis galvanometer motor performs rotational motion based on received control signals. When the motor rotates, it drives the connected X-axis reflecting mirror to change its angle. Assuming the laser beam initially incidents vertically onto the mirror, when the mirror rotates around the X-axis by a certain angle, the reflection direction of the laser changes horizontally (along the X-axis) according to the law of reflection.

For example, when the motor rotates positively by a certain angle, the mirror reflects the laser to the left; when rotating negatively, the laser reflects to the right. This achieves oscillating scanning of the laser along the X-axis direction.

Y-Axis Oscillation Principle:
Similarly, the Y-axis galvanometer motor drives the Y-axis reflecting mirror to rotate. When the Y-axis mirror rotates, the reflection direction of the laser changes vertically (along the Y-axis direction). The coordinated oscillation of both axis mirrors enables the laser to reach any designated position within the two-dimensional plane.

For instance, to weld a circular seam on a plane, by controlling the X-axis and Y-axis galvanometer motors to make the laser scan along a circular path with specific radius and angular velocity, a circular weld seam can be completed.

Scanning Modes and Motion Trajectory Control

Vector Scanning Mode:

In vector scanning mode, the welding pattern's geometric shape is decomposed into a series of vector segments. The drive controller precisely regulates the galvanometer's oscillation and laser emission by calculating the required angular variations for each vector segment and corresponding laser pulse durations.

For instance, when welding a triangular seam, the system first identifies the three vertex coordinates of the triangle. It then computes the necessary angular adjustments for both X and Y-axis galvanometers to transition between vertices, synchronizing laser activation/deactivation timing to achieve continuous welding along the triangular contour.

Raster Scanning Mode:

Raster scanning employs a systematic pattern, typically adopted for large-area welding or surface treatment. In this mode, the laser scans along the X-axis with predefined step intervals. Upon completing each line scan, the Y-axis advances incrementally before initiating the next parallel scan path – analogous to weaving a laser "grid" across the surface.

A practical application involves welding extensive rectangular circuit boards: the laser first scans left-to-right along the X-axis, then shifts minutely along the Y-axis for subsequent parallel scans until full area coverage is achieved.

Integrated Constant-Temperature Galvanometer Coaxial Vision Scanning Welding System Product Diagram

Songsheng Optoelectronics has developed an Integrated Constant-Temperature Galvanometer Coaxial Vision Scanning Welding System in response to market demands. This system provides a definitive solution to precision welding challenges in microelectronics, significantly improving welding yield rates and production efficiency in electronic manufacturing.

Featuring a Multi-Point Coaxial Optical Path System, the specially designed infrared lens ensures perfect alignment of the laser beam, imaging focal point, and infrared temperature measurement spot across the entire working range—even when deviating from the lens center. This innovation delivers a true temperature-monitored processing system.

Advantages of Galvanometer Coaxial Vision Scanning Welding System in Microelectronics Applications:

1. Coaxial integration of temperature measurement, imaging, laser processing,      guidance lighting, and illumination ensures advanced laser optical performance. 

2. Closed-loop temperature feedback with PID robust control is essential for achieving maximum production yield in laser processing.

3. The infrared temperature sensor responds 1,000× faster than conventional      thermometers—faster response enables superior welding quality.

4. Adjustable spot geometry adapts optimally to various pad sizes, enabling uniform      heating across different joint configurations.

5. Telecentric scanning lens design eliminates common optical aberrations, ensuring      consistent precision across the entire working field.

6. Multi-element collimating/focusing lenses (diffraction-limited design) outperform      standard single/doublet lenses in optical quality—our system employs stacked      diffraction-limited lens assemblies for optimal performance.

7. Proprietary multi-channel coaxial technology integrates laser, imaging, thermometry, and alignment beams into a single optical path.