How does fiber laser marking machine make different color on stainless steel?

Nov 17, 2024

Fiber laser marking machines can create different colors on stainless steel by using precise control over the laser’s power, frequency, and speed, which induces various physical and chemical changes in the surface of the material. These changes are primarily related to the way light interacts with the surface and how heat affects the metal’s properties. Here’s how it works:

1.Oxidation Layers:

When the fiber laser is focused on the stainless steel surface, it heats the metal to a high temperature. As the metal heats up, it forms thin oxidation layers that produce different colors. The thickness of these layers depends on the intensity and duration of the laser pulse. Each layer of oxidation reflects light differently, producing colors ranging from gold, yellow, blue, purple, and green, depending on the thickness of the oxide film.

2.Heat Treatment and Microstructure Changes:

At higher intensities, the laser can change the microstructure of the metal surface, leading to color changes. The laser can create different heat-affected zones, causing the steel to exhibit a rainbow-like effect that varies in color as the laser power is adjusted.

3.Surface Texture Modification:

The laser can also create micro-textures on the steel surface that interact with light in different ways, further influencing the perceived color. This can add another layer of complexity to the color outcome.

4.Laser Parameters:

By adjusting parameters like pulse frequency, power, and scanning speed, operators can control the intensity of these effects. Lower power settings tend to produce subtle color shifts, while higher power settings can create more dramatic results.

To summarize, the different colors on stainless steel are a result of a combination of factors like oxidation, microstructural changes, and the specific laser parameters used during the marking process.