The UV laser marking machine operates based on the principle of cold marking, utilizing a high-energy ultraviolet (UV) laser beam to alter or remove material surfaces without generating significant heat. Here is the breakdown of its working principle:
1. UV Laser Generation
The machine uses a UV laser source (typically 355 nm wavelength), generated by:
A solid-state laser (e.g., Nd:YAG or Nd:YVO₄ crystal) that emits infrared light.
The light passes through a frequency tripler, converting it to ultraviolet (355 nm).
This short-wavelength UV light has high photon energy, enabling precise interactions with materials.
2. Cold Ablation & Photochemical Reaction
Unlike traditional laser marking (which relies on heat), UV laser marking works via:
Photochemical Breaking of Molecular Bonds:
The high-energy UV photons directly break chemical bonds in the material (e.g., plastics, glass, or sensitive substrates).
This causes non-thermal ablation, meaning minimal heat-affected zones (HAZ).
Material Removal or Color Change:
Some materials absorb UV light and undergo a color change (e.g., through oxidation or carbonization).
Others experience micro-level vaporization, leaving a clean, high-contrast mark.
3. Precision Marking via Galvanometer & Control System
The UV laser beam is directed by high-speed galvanometer mirrors, controlled by a computer.
The focusing lens narrows the beam to a fine spot (as small as 10–30 µm), allowing ultra-fine details.
The CNC system follows programmed patterns (text, barcodes, logos) to mark the material accurately.
4. Applications & Advantages
Materials Suitable for UV Laser Marking:
Plastics (ABS, PC, PVC)
Glass, ceramics
Sensitive electronics (PCB, silicon wafers)
Metals (with special coatings)
Advantages:
High precision (micron-level marking)
No thermal damage (ideal for heat-sensitive materials)
Permanent, wear-resistant marks
Environmentally friendly (no inks or chemicals)
