In laser oscillation welding, it can be classified into single-pendulum and double-pendulum welding guns based on the number of the core optical components - the mirrors. This article, based on the definition of "single pendulum as a single mirror system and double pendulum as a double mirror system", elaborates on the technical differences between the two.
1. Pendulum Laser Welding Gun: Single Oscillation Mirror System
System Composition:
The core component of the pendulum laser welding gun is a single oscillation mirror system. This system consists of only one reflective mirror driven by a high-speed servo motor.
Motion mechanism and capability:
This single mirror usually controls the laser beam to reciprocally deflect along a single axis. Therefore, the movement trajectory of the laser focus on the workpiece surface is limited to a one-dimensional linear oscillation, such as a straight line, a line segment, or a high-frequency reciprocating scan along the X-axis direction.
Function and Limitations:
Function: Achieve oscillation in a single direction. Primarily used for stirring the molten pool in a specific direction, or for compensating for gaps during welding through lateral micro-oscillation.
Limitations: It is unable to generate any two-dimensional planar trajectories (such as circles). Its movement capabilities are extremely limited and it cannot achieve complex molten pool stirring patterns.
II. Dual-oscillator Laser Welding Gun: Dual Oscillator System
System Composition:
The core of the dual-oscillator laser welding gun is a dual-oscillator system. This system consists of two independent high-speed servo motors driving reflective mirrors. Generally, the first oscillator controls the deflection in the X-axis direction, and the second oscillator controls the deflection in the Y-axis direction.
Motion mechanism and capabilities:
By controlling the deflection angles and movement timings of these two mirrors, it is possible to precisely synthesize any two-dimensional plane trajectory of the laser focus on the workpiece surface. These trajectories include but are not limited to circles, ellipses, infinity shapes, and other custom complex patterns.
Functions and Benefits:
Function: Achieve complex two-dimensional oscillation.
Advantages: Through two-dimensional trajectory oscillation, it can more effectively stir the molten pool, break dendrite growth, promote gas escape, thereby significantly improving the weld formation quality, suppressing pores and cracks, and enhancing the bridging ability for assembly gaps.
III. Summary of Core Differences
IV. Selection of Application Scenarios
Simple Pendulum Welding Gun (Single Oscillation Mirror): Suitable for simple applications where only a single-direction swing is required to meet the process requirements, such as widening the weld seam in a specific direction, or performing basic swing welding in situations where the requirement for the stirring mode is not high. Its application scope is relatively narrow.
Double pendulum welding gun (double mirror): It is currently the mainstream technology for laser oscillation welding. It is suitable for most applications that require complex trajectory oscillation to improve weld quality, such as welding of aluminum alloys, high-strength steels, etc., as well as precision processing with high requirements for weld formation and porosity rate.
Conclusion: Based on the definitions of "single mirror" and "double mirror", the fundamental difference between the single pendulum and double pendulum laser welding guns lies in the number of core optical components. The single mirror system can only achieve one-dimensional oscillation and has limited movement capabilities; while the double mirror system can achieve two-dimensional planar oscillation and possesses the ability to generate complex trajectories, thus having an absolute advantage in the welding process effect.