Polygon Scanners For Laser Material Processing

In high-precision laser material processing, ultra short pulse laser source is used for polygon scanner scanning to reduce the heat affected zone. However, in order to prevent the material from overheating, system technology is required to quickly distribute the required high power to the surface.

1. System Technology

There are two possible ways: on the one hand, increase the parallelism of the process, on the other hand, increase the speed of the process. Improving the scanning speed requires low pulse energy and high repetition rate. At high repetition rate, the maximum speed of galvanometer scanner is not enough to meet the necessary pulse interval, so the laser must operate at low power.

The polygon mirror of the polygon scanner rotates at high speed and constant speed, so as to improve the maximum scanning speed. This allows low pulse overlap to make full use of laser power and obtain the best processing results. In order to realize two-dimensional machining, the scanning line is moved by moving the workpiece or using an additional galvanometer. The pulse and position of the laser beam are precisely modulated in synchronization with the positions of the polygon and the second axis.

2. Typical System Parameters

Different spatial resolutions can be achieved according to the control system and scanning head configuration used.