What Are the Reasons for the Laser Scanner Galvanometer Scanning Error?

Laser scanner galvanometer technology has been widely used in various fields and industries, such as laser marking, laser stage, and laser rapid prototyping, due to its high precision, fast speed, and convenient control. However, in the process of laser scanner galvanometer, errors may occur due to the simplification of the verification method, which is a geometric algorithm error. To solve this error, hardware or software correction methods can be adopted. Compared with hardware correction, software algorithms are generally used for correction, which effectively saves costs and time. Adapting effective correction algorithms for laser scanner galvanometer can reduce scanning errors and effectively ensure the accuracy of the scan pattern. Based on this, this article briefly analyzes the causes of errors in laser scanner galvanometer.

Causes of errors in laser scanner galvanometer

In laser processing, the scanning galvanometer rapidly scans, and the coordinates of the scanning points in the scanning plane have a corresponding relationship with the deflection angles of the x-axis and y-axis galvanometers. There is a functional relationship between the coordinates of the scanning points and the deflection angles of the x-axis and y-axis galvanometers. By controlling the servo motors of the x-axis and y-axis galvanometers, which determine the corresponding deflection angles, a certain input voltage can be given to obtain the corresponding deflection angles.

During the scanning process of the laser galvanometer scanner, the deflection angles of the galvanometer are calculated for the coordinates of the scanning points in the plane, and the input voltage of the servo motor determines the deflection angles of the galvanometer. The 16-bit binary digital signal of the motion control card is converted into an analog signal as an input voltage. Therefore, from this perspective, the scanning points are determined by the x-axis and y-axis digital signals of the 16-bit binary motion control card.

There is a complex relationship between the deflection angles of the x-axis and y-axis galvanometers and the coordinates of the scanning points, and precise conversion through corresponding formulas requires a longer time, which puts a severe test on the processor of the control unit, and also affects the real-time performance of high-speed scanning. To simplify this process, the relationship between the deflection angles of the x-axis and y-axis galvanometers and the coordinates of the scanning points is transformed into a linear relationship. Although this simplification can simplify the entire calculation process, it inevitably produces corresponding errors, resulting in distortion and deformation of the scanned pattern, which is a geometric distortion.

The error in laser scanner galvanometer is essentially caused by algorithm distortion

Unlike the errors caused by optical components, the error in laser scanner galvanometer is caused by approximations and simplifications in system control. The distortion generated by the laser scanner galvanometer in scanning is a typical distorted image, that is, the difference between the coordinates of the scanning points and the actual coordinates. To correct this error, hardware or software correction methods are generally used, and software algorithms are mostly used for correction. Compared with hardware correction, software correction is more cost-saving and can effectively correct geometric distortions caused by approximations and simplifications, correcting errors in the galvanometer system. Software correction focuses on the errors in the entire galvanometer system, and corrects the errors caused by various influencing factors based on the requirements of accuracy.