Laser Marking Application Case: Deep Engraving on Stainless Steel

Equipment Configuration: Chuangxin MFP-50W Fiber Laser

Deep engraving and standard marking are two different things—standard marking only changes the surface color, while deep engraving “carves” a groove with measurable depth into the material. Stainless steel has high hardness and fast thermal conductivity, making deep engraving a demanding application for both equipment and process.

I. Deep Engraving Principle

Deep engraving relies on laser layer-by-layer material removal—high-energy-density laser pulses vaporize, melt, and expel the stainless steel surface layer by layer, forming a V-shaped or U-shaped groove.

Key control factors:

• High power: Provides sufficient energy density to vaporize stainless steel
• Slow speed: Increases laser dwell time per unit area
• Multiple scans: Depth is accumulated layer by layer; a single pass cannot create depth
• Low frequency: Higher single-pulse energy, stronger penetration

II. Equipment Configuration

The 50W model is the “sweet spot” for deep engraving—sufficient energy with good cost-effectiveness. The 20W model can also do deep engraving, but at a very slow speed; the 30W model is barely adequate; only the 50W model achieves a balance between efficiency and depth.

III. Parameter Reference

Recommended Starting Parameters

Depth and Passes Reference

IV. Key Technical Points

1. Layered Engraving

Do not try to engrave to full depth in one go. Control each layer’s engraving depth to 0.05-0.1mm, allowing cooling intervals between layers. Engraving too deep in a single pass can lead to:

• Slag accumulation at the bottom
• Edge overheating and deformation
• Laser focus shift (focal point changes as depth increases)

2. Focus Compensation

As engraving depth increases, the distance from the material surface to the lens changes. When depth exceeds 0.3mm, it is recommended to re-focus every few layers, or use a dynamic focusing system.

3. Auxiliary Air Blowing

Deep engraving generates a significant amount of slag and fumes. Compressed air or nitrogen blowing is strongly recommended for:

• Removing slag to prevent re-melting
• Cooling the processing area to reduce the heat-affected zone
• Protecting the field lens from fume contamination

V. Effect Characteristics

• Depth: 0.1-1.0mm, controllable
• Bottom Texture: Matte, with fine texture
• Edges: Clean, with a slight heat-affected zone
• Color: Dark gray to black
• Wear Resistance: Excellent, deep marks are nearly impossible to wear away

VI. Precautions

1. 50W deep engraving limit: Depths above 1mm require a large number of passes with extremely low efficiency. If the customer needs depths exceeding 1mm, consider higher power (70W/100W) or mechanical engraving
2. Thermal deformation: Thin stainless steel sheets (<1mm) are not suitable for deep engraving as they are prone to deformation
3. Cooling intervals: Let the machine rest for 30 seconds every 5-10 passes to avoid laser overheating
4. Field lens protection: Deep engraving generates heavy fumes; regularly check the field lens for contamination
5. Material limitations: 304 stainless steel produces better deep engraving results; 316 is harder due to its molybdenum content and is more difficult to engrave

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VII. Application Scenarios

• Mold numbers / marks
• Tool steel stamps
• Deep engraved stainless steel nameplates
• Industrial valve / pipe fitting identification
• Tool / instrument brand marks
• Permanent identification requiring tamper resistance

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Summary: With a 50W fiber laser, practical depths of 0.3-0.5mm can be achieved for deep engraving on stainless steel. The key is layered engraving + air blowing + focus compensation. If the customer only needs shallow engraving (0.1mm level), 5-8 passes are sufficient, with good efficiency and cost-effectiveness.

*Deep engraving causes greater wear on equipment. Regular maintenance of the laser source and field lens is recommended.*