SPI fiber laser used in stainless steel marking

As we all know, stainless steel is a widely used engineering material in the world today, and it can be used in various industries and fields. From consumer goods to cooking utensils, from surgical instruments to roofs, stainless steel is the material of choice. There are more than 150 grades of stainless steel, and the degree of difference in surface finish is even more dazzling. There is always one of them that can meet everyone's requirements. In contrast, fiber lasers are also widely used industrial marking tools. The combination of the two will give you unexpected results.　　Many stainless steel products and parts need to be printed with a logo, whether the logo is a simple letter and number indicating the date of production, or a finer bar code or two-dimensional code, fiber lasers can do it. Whether these logos are single lines, outlines, or filled fonts-no matter what your requirements, as long as you can express it on paper, fiber lasers can copy it to metal. Some markings are very delicate, such as functional markings that are usually used as scales on various tools or instruments. Some markings are not very important, such as decorations or decorations, and fiber lasers can also be used for marking. The size of the SPI fiber laser is only the size of a shoebox, but it can provide 10-40mW focused nanosecond pulses. When marking the material, it can change the color of the material surface without being affected by heat to form a permanent mark. Used in conjunction with an optical scanning galvanometer, any pattern can be printed, making it a widely used marking tool.　　 The physical and chemical properties of stainless steel and its response to lasers are worthy of study, because the visual effects ultimately achieved may be completely different depending on the characteristics of the incident light and the grade of stainless steel. A laser with enough pulse energy will locally melt the metal surface, and the molten part will produce a series of pits and react with the oxygen in the environment to turn into a dark mark, and the outline can be touched, with a bumpy feeling. As the pulse energy increases, some materials are vaporized and air pressure is generated at the melting point of the cavity, resulting in a splash effect, which greatly improves the visual quality of the mark. The engraving effect can also be obtained after repeated markings back and forth. If you choose a lower energy density and a longer processing time, you will get a completely different effect: dark black marks can also be produced when the metal does not melt, which is usually called annealing marking (metallurgical Experts do not recognize this name). In fact, this should be called black oxidation marking. Its contrast is very high, but it will not affect the roughness or texture of the material surface. In the field of consumer goods, this type of mark is widely used. However, people are more interested in its application in surgical instruments. Surgical instruments have strict requirements for marking quality, because they must ensure that there is no quality degradation or partial rust after repeated sterilization treatments. This is a serious challenge, requiring very careful control of pulse conditions and heat input. The flexibility and controllability of fiber laser pulses make it ideal for this type of application.　　 Fiber laser can produce black marks, so can it produce white? The answer is yes. Fiber lasers can also make pure white marks on stainless steel. And the same is achieved by controlling the energy of the laser. The laser used to generate grid points has short pulses and low energy, so that the surface of stainless steel can only produce a small amount of melting, and it has been solidified before any harmful atmospheric oxidation occurs. This can produce a strong white mark. This kind of logo is more beautiful, so it is often used on various consumer products, such as cameras and mobile phones. In addition, this type of marking will have a significant impact on the physical properties of the material, such as affecting the wetting characteristics of the material. The use of fiber lasers to change the characteristics of the material surface is a hot spot in current research and development.　　Gray marking effect can also be achieved by changing the distribution density of dots or changing the energy density of all individual dots. The former is a more commonly used method in traditional printing technology.　　 But the world is not black and white, can lasers produce color marks? Absolutely, without any pigments or additives, just by changing the energy of the light, we can use lasers to make colorful marks on the surface of stainless steel. The principle is to generate an oxide film whose thickness is precisely controlled on the local surface of stainless steel. Due to the diffraction effect, oxide films of different thicknesses can present different colors. However, this technology is currently only realized in scientific research, and has not formed a broad market and industrial application, because its processing speed is very slow and its color tone is difficult to copy or match the PANTONE (International Color Card) standard. But it is indeed very visually striking, and is a good example of the stability and versatility of the laser light source.