Speed and Precision Specifications Decoded

Galvo spec sheets can be confusing. Here’s what the numbers actually mean for your marking results.

Marking Speed vs. Scan Speed

These are different metrics:

• Scan speed — How fast the galvo mirrors can rotate (measured in radians/second or degrees/second). This is a raw mechanical specification.
• Marking speed — How fast the laser actually marks on the workpiece (measured in mm/s). This depends on scan speed, F-theta focal length, and laser parameters.

When manufacturers advertise “10,000 mm/s marking speed,” that’s typically the maximum linear marking speed under ideal conditions. Real-world marking speed depends on:

• Material and required mark depth
• Mark complexity (straight lines vs. curved paths)
• Jump speed (repositioning between mark segments)
• Laser pulse frequency

Precision: Repeatability vs. Accuracy

• Repeatability — Can the galvo return to the exact same position repeatedly? High-quality galvo scanners achieve ±0.005 mm repeatability.
• Accuracy — Is the mark placed at the exact intended position? This depends on calibration, F-theta quality, and thermal stability. Typical accuracy: ±0.01–0.02 mm across the field.

For most marking applications, both specifications are more than adequate. Precision becomes critical for:

• Micro-marking (characters under 0.5 mm height)
• Array marking (placing identical marks with tight spacing)
• Vision-guided marking (where camera alignment must match galvo positioning)

Galvo Scanner Quality Tiers

The galvo scanner is not the component to save money on. It directly determines marking speed, precision, and long-term reliability. A premium galvo scanner pays for itself in reduced maintenance and consistent mark quality.

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