Etching
Laser Etching Overview: Laser etching is a precise, non-contact process that creates shallow surface relief (typically <25 µm deep) on materials by altering their profile, producing raised, sunken, frosted, or textured marks. It differs from laser marking (primarily color/texture change with no depth) and laser engraving (much deeper material removal, often 250+ µm). Etching is faster, leaves minimal heat-affected zones, and works on flat or curved surfaces. A single laser system (e.g., fiber, CO₂, or UV) can handle marking, etching, and engraving by adjusting power, speed, and passes.
Process and Technical Details:
The laser beam is modulated (power varied) while scanning the surface via:
Galvanometer (galvo) scanners: Fast-moving mirrors for high-speed etching of small/curved parts (e.g., up to 1–2 m/s scan speeds). Often combined with rotary fixtures.
Linear motion stages: XYZ tables for larger parts like signs or monuments.
Typical parameters include pulse durations in nanoseconds to femtoseconds, spot sizes of 10–50 µm, and depths controlled to 5–50 µm. This enables high-resolution patterns (including photos via dot dithering) with excellent repeatability.
Material-Specific Applications and Technical Notes:
Metals: (aluminum, steel, stainless, brass, copper, titanium) The laser briefly melts a thin layer, causing micro-expansion and resolidification into a raised, rough-textured mark (<25 µm high). Marks can appear dark, light, or gray depending on parameters.
Applications: Automotive/aerospace part numbering (VINs, serials), medical device traceability (UDI codes on implants), oil/gas components, tooling. Faster than engraving; ideal for high-volume production.
Advantages: Corrosion-resistant marks; minimal distortion on thin parts.
Glass and Ceramics: Removes <25 µm of material, creating a rough, frosted (translucent) texture via micro-ablation or thermal fracturing.
Applications: Decorative etching on wine glasses, bottles, mugs, mirrors, awards; industrial lot/expiration codes on beverage/pharma containers; microelectronics glass substrates with alignment marks or serials.
Advantages: Clean, precise on curves; no consumables vs. sandblasting or chemical etching.
Natural Stone: (granite, marble) Micro-ablation creates light-colored marks on dark backgrounds by roughening the surface (<25–50 µm depth). Uses dot-matrix patterns for grayscale images.
Applications: Tombstones, memorial plaques, architectural signage, awards.
Advantages: Superior visibility and speed over sandblasting or mechanical engraving; complex photos/drawings possible.
Polymers and Plastics: Includes foaming (light-colored raised marks <50 µm) or carbonization. Low heat input prevents damage.
Applications: Consumer goods, signage, medical devices (syringes, catheters), electronics housings.
Semiconductors/Microelectronics: Ultra-shallow etching (<10–15 µm) on wafers, flip-chips, and mold caps for serial numbers, QR codes, and backside tracking without harming circuitry. Critical for high-value chips where deeper marks could cause defects.
Overall Benefits and Use CasesLaser etching is fast (seconds per mark), clean (no inks/chemicals), permanent yet shallow, and highly flexible for one-off to mass production. It excels in industries requiring traceability (medical, automotive, aerospace — compliant with standards like FDA UDI), customization (promotional items, awards), and delicate components (electronics). Modern systems integrate with CAD software and vision systems for automated, high-precision results on virtually any material.