What is the Basic Principle of Laser Marking?

The basic principle of laser marking is to use a high-energy laser beam to irradiate the surface of the object, and the light energy is instantly converted into heat energy, so that the surface of the object quickly evaporates, exposing the deep layer of material, or the light energy causes the chemical and physical changes of the surface material to engrave. Traces, or use light energy to burn off part of the material, so as to engrave any required text and graphics on the surface of the object, which can be used as a permanent anti-counterfeiting mark.

 

The Mechanism of Laser Marking 

Laser marking is under the action of a high-energy laser beam to cause the processed workpiece to undergo physical and chemical reactions such as melting, vaporization, heating and discoloration, thereby leaving a permanent mark on the surface of the workpiece. According to the different laser energy used, the mechanism of laser marking can be divided into the following types

Heating to Change Color Marking 

When most materials (especially some non-metallic materials, such as plastic, paper, rubber, etc.) are heated by laser, the material itself undergoes a chemical change, which will cause the surface color of the marked workpiece to change or make its surface gloss brighter. Therefore, this mechanism can be used for marking.

This change in the color of the material during laser heating only appears on the surface of the material, which is caused by changes in the metallurgical structure of metals or changes in the chemical composition of non-metals. It is generally difficult to predict the color change of these materials, especially plastic materials when the laser is applied.

Most of the laser marking machines in mask mode use this method for marking. This marking method requires low power density, the temperature of the marking part is below the melting point of the material, and the deformation of the material caused during marking is extremely small, which is suitable for laser marking on non-metallic materials.

Melt Marking

After the metal is heated to the melting point, the color of its surface will also change after the metal's decomposition due to the oxidation of the metal or the incorporation of other impurities. For example, the color of the marks produced by some steels will become darker after melting, but when there is a layer of oil film on the surface, marks with great contrast will be produced on the surface.

This method can also be used for laser marking. Since the surface profile of the metal does not change before and after marking, this type of marking method has great advantages in certain applications. For example, the surface of medical skeletal support plates, artificial spine connectors, cardiac pacemakers, etc., are required to be as smooth as possible, so it is best to use this method for marking.

The method of fusion marking is also suitable for some plastic materials. When they melt, they will form grooves on the surface or change the rest of the surface structure.

Vaporization Marking

Most materials will evaporate and vaporize when the surface temperature is higher than the melting point. For example, metal materials such as steel, aluminum, titanium, and copper.

 

Features of Laser Marking

Laser marking is non-contact processing. It can be marked on any conductive surface without deformation or stress. It is suitable for metal, plastic, glass, ceramics, wood, leather and other materials; it can mark barcodes, numbers, Characters, patterns, etc.; the mark is clear, permanent, beautiful, and can be effectively anti-counterfeit. Laser marking can conveniently use a computer to automatically control graphics and trajectories. It has the characteristics of fast marking speed, low operating cost, and no pollution, which can significantly improve the grade of the marked products.

Huiyao has the Laser Marking Machine  for sale; if you want to learn more about our products, please contact us.