The line width of laser marking can be less than 12pm, and the depth of the line can be less than 10pm. It can mark the surface of small parts in millimeters. Laser marking can easily use computer for automatic control of graphics and heat traces, and has fast marking speed, low operating cost, no pollution and other characteristics, can significantly improve the grade of the marked products.
There are three laser marking methods. The galvanometer laser marking method was introduced last time, and this time I will introduce the other two.
(1) Dot matrix laser marking method
One or several small lasers are used to emit light pulses at the same time, and one or more laser pulses are ablated on the surface of the workpiece to ablate uniform and fine pits (the diameter of the pits is generally 15pm) after passing through a mirror and a focusing lens, the characters and patterns marked by the laser are composed of multiple small round pits. Generally, the vertical stroke is up to seven points, and the horizontal stroke is up to five points, forming a 7x5 array, as shown in the figure below.
(2) Mask laser marking method
The structure of mask marking is composed of TEACO laser and mask. The mask is made of high temperature resistant metal sheet and other materials. Characters, barcodes or patterns are dug out on the mask by hollowing, mechanical engraving or photographic etching. The laser beam emerges from the hollowed-out gap of the mask to form the shape of the character barcode or pattern. After the converging lens, the pattern reduced according to the required scale is reflected on the surface of the workpiece, and ablated into a mark. The following figure shows the principle of mask laser marking method.
