Why UV lasers can mark black on plastic 

When a UV laser irradiates plastic, it causes its surface to turn black. The reason behind this phenomenon is that the laser emitted by the ultraviolet laser has high energy, which triggers a photochemical reaction when it hits the plastic surface. The energy of ultraviolet laser can break the chemical bonds in the plastic molecules, causing the molecular structure to change. This change usually manifests itself as carbonization of the surface layer of the plastic, causing the surface to appear black.

In addition, the laser emitted by the ultraviolet laser also has a high concentration, which allows the laser energy to create high temperatures on the plastic surface. Under the influence of high temperature, plastic molecules will accelerate oxidation and further promote the carbonization process. Therefore, the plastic surface after being irradiated by the ultraviolet laser will not only turn black, but also become rougher, and sometimes even produce tiny bubbles or cracks.

It should be pointed out that different types of plastics will have different blackening degrees and morphological changes after being irradiated by ultraviolet laser. This mainly depends on the chemical structure, molecular weight and other related factors of the plastic. In practical applications, we need to select appropriate parameters and materials according to specific conditions to ensure processing quality and applicability.

When an ultraviolet laser irradiates plastic, its surface will turn black. This is because the high energy of the ultraviolet laser triggers a photochemical reaction and the carbonization process of the plastic molecules. Understanding this phenomenon will help us better apply UV lasers and provide guidance for material processing.