Lasers can produce color, but there are restrictions on materials. Today we will tell you the difference between common materials. They are: plastic, stainless steel and other materials.
1. Different grayscale marking of plastics：
The basic principle of white plastic laser marking is similar to the general principle of laser marking, but there are some specific adjustments and precautions. Here are some of the ways we mark white plastics in dark colors：
When actually operating the UV Laser marking machine, in order to obtain a black or dark logo on the surface of the white plastic, we mainly control the effect by adjusting the different gray values of the UV Laser marking machine. This usually requires increasing the laser power of the UV Laser marking machine to generate sufficient heat energy to melt the surface of the material and cause color changes.Increasing the number of marking times can improve the depth and saturation, and enhance the contrast. At the same time, adjusting the focus of the UV Laser marking machine marking head can make the laser beam more concentrated, the effect is deeper, and the color is deeper. Controlling the marking speed is also critical: reducing the marking speed of the UV Laser marking machine extends the laser action time, the material absorbs more energy, and the marking color usually deepens. The material itself also has an impact. Some plastics containing colorants such as carbon black absorb laser energy more easily, and the color is deeper when marking with UV Laser marking machine .In addition, we also need to strengthen other parameters such as pulse width and frequency according to the specific UV Laser marking machine model and plastic type to achieve better results. Special attention needs to be paid. Although laser marking can produce permanent marks, excessive input of energy may cause plastic to deform or burn, which is less than we need to find a balance between ensuring the color effect and avoiding irreversible damage to the material.
2. Stainless steel laser marking：
The principle of stainless steel laser marking is mainly to use the interference effect of the laser on the surface of stainless steel to form different color effects by controlling the laser parameters and material reactions of the UV Laser marking machine. Specifically, there are mainly the following ways: The generation of colored hydroxides, the interference of multi-layer structures, and the influence of observation angles.
Generate colored oxides：
When the laser beam is irradiated on the surface of stainless steel, it will oxidize its metal elements (such as iron, chromium, and nickel).
These oxides themselves have specific colors, and these colors can be controlled by changing the parameters of the laser (such as power, frequency, etc.).
Interference effect of colorless transparent oxide film：
By appropriately selecting the laser parameters, a very thin layer of colorless transparent oxide film can be produced on the surface of stainless steel.
This layer of oxide film will undergo film interference phenomenon under the irradiation of light, that is, the interaction between incident light and reflected light.
Depending on the wavelength, some light is strengthened and some is offset, resulting in various colors.
Multi-layer structure interference：
In addition to the interference of a single layer of oxide film, a multi-layer structure can also be formed by laser processing, each layer has a different thickness and refractive index.
When light passes through these multi-layer structures, complex interference patterns are produced, showing colorful colors.
Influence of observation angle：
The color effect of stainless steel color marking will also change with the change of observation angle, because from different angles, the interference conditions of light will be different.
Our UV Laser marking machine is an effective tool for color marking of stainless steel because it can provide flexible pulse width and frequency adjustment to accurately control the thermal effect and oxidation process of the material. This allows users to create colorful marking effects as needed without having to rely on chemical coloring methods.
Our Eagle Laser has been continuously manufacturing laser equipment for many years, and the research on stainless steel color is still being explored. We firmly believe that Eagle Laser can develop better laser equipment for the stainless steel color industry in the future.