Laser Marking of High-Reflectivity Metals: Copper, Gold, and Silver

In the field of laser marking, high-reflectivity metals such as copper, gold, and silver have always been a “challenge.” Why? Because they have extremely low absorption rates for conventional 1064nm fiber lasers — most of the laser energy is reflected away. Not only does this result in poor marking quality, but the reflected light can also damage the laser source.

**So how should high-reflectivity metals be marked?**

**Option 1: UV Laser (355nm)**
The shorter the wavelength, the higher the material’s absorption rate. A 355nm UV laser has a much higher absorption rate for copper, gold, and silver than infrared lasers, enabling clear, fine markings with minimal heat-affected zones — ideal for precision components.

**Option 2: Green Laser (532nm)**
The green laser operates in the visible light spectrum and offers significantly better absorption rates for high-reflectivity metals than infrared lasers, making it a reliable choice for marking copper, gold, and silver.

**Option 3: Surface Pretreatment Assistance**
If you only have a fiber laser available, surface pretreatment (such as applying marking agents or surface oxidation treatment) can improve absorption rates, though this adds to process costs.

**Practical Applications:**
– Electronic components: chip pins, circuit board copper foil marking
– Jewelry: brand logos and purity marks on gold and silver items
– Precision terminals: connector terminal identification

**Summary:** The best choice for high-reflectivity metal marking is a UV or green laser. If conditions are limited, fiber lasers with surface pretreatment can also get the job done.