What Is the Working Principle of a Laser Marking Machine?

For manufacturers seeking permanent, high-precision identification, the laser marking machine has become a standard solution across industries. To make informed purchasing decisions, it’s essential to understand the working principles behind this technology.

1. Basic Structure of a Laser Marking Machine

A typical system consists of four main components: the laser source (fiber, CO₂, or UV), scanning galvanometers (moving mirrors), a focusing lens (f-theta lens), and a control unit. The laser source generates the beam, which is directed by mirrors to precisely trace the desired pattern on the material surface.

2. Interaction Between Laser and Material

When the focused beam hits the material, energy is absorbed, causing localized changes. Depending on the settings and material type, this can result in engraving (removing material), annealing (creating color changes through oxidation), foaming (in plastics), or carbon migration. No mechanical contact or inks are required.

3. Role of Wavelength and Pulse Control

Different materials respond to specific wavelengths. Fiber lasers (1064 nm) work well on metals and some plastics, while CO₂ (10.6 μm) suits organic materials like wood or glass. UV lasers (355 nm) enable cold marking with minimal heat input, ideal for sensitive components. Pulse duration and frequency also affect depth and contrast.

4. Motion Control and Software Integration

The galvo system moves the beam at high speed based on digital vector or raster data. Modern laser marking machines integrate with factory systems via PLC or Ethernet, allowing real-time data marking such as serial numbers, barcodes, or QR codes.

For buyers, understanding these principles helps in selecting the right laser type, power, and configuration for specific applications. Look for systems with stable beam quality, adjustable parameters, and reliable software compatibility to ensure long-term performance and traceability in production environments.