Laser Marking of High-Reflective Metals: Copper, Gold, Silver

# Laser Marking of High-Reflective Metals: Copper, Gold, Silver

In the field of laser marking, high-reflective metals such as copper, gold, and silver have always been a “challenge.” Why? Because their absorption rate of conventional 1064nm fiber laser is extremely low — most of the laser energy is reflected away. This not only results in poor marking quality, but the reflected light can also damage the laser source.

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

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

**Solution 2: Green Laser (532nm)**
Green laser operates in the visible light band and offers significantly better absorption for high-reflective metals compared to infrared lasers. It is a reliable choice for marking copper, gold, and silver.

**Solution 3: Surface Pretreatment Assistance**
If only a fiber laser is available, surface pretreatment (such as applying marking agents or surface oxidation treatment) can improve absorption, though this adds process steps and costs.

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

**Summary:** The best choice for marking high-reflective metals is UV or green laser. If conditions are limited, fiber laser combined with surface pretreatment can also achieve acceptable results.