Fine-Tuning Focal Height on the Ray5 20W for Uneven Materials

The Ray5 uses a fixed focal length — the beam is sharpest at exactly the right distance from the lens. Most materials are flat and this is easy. Uneven, warped, or curved materials require a different approach.

Understanding Focal Length

The Ray5 20W focuses at approximately 58mm from the laser module to the work surface (using the included spacer tool). At this distance the beam spot is smallest = maximum power density.

Moving closer or further defocuses the beam — spot gets larger, power density drops.

When Focal Height Matters

• Warped plywood or MDF (common)
• Leather that isn't lying flat
• Objects with varying height (3D surfaces)
• Thick materials where top ≠ middle
• Deliberately defocusing for softer engraves

Checking Your Focus

1. Place material, use spacer to set height
2. Run a focus test — a diagonal line from 0 to -5mm Z offset in 0.5mm steps
3. The sharpest, thinnest line = correct focus
4. Mark that Z value

Fixing Warped Material

Thin warped ply/MDF:

• Dampen back lightly with water, place flat under weight for 30 min
• Or: use strong tape across surface to hold flat on honeycomb

Thick warped boards:

• Clamp corners to the bed with binder clips through honeycomb
• Cut into smaller sections that lay flat

Leather:

• Use hold-down pins around perimeter
• Small weights on corners during engraving

Defocusing Intentionally

Deliberately raising or lowering material from focal point creates larger, softer beam spots. Useful for:

Scanning Compensation for Uneven Material

For large flat engrave jobs on materials with known height variance:

1. Map the height at 9 points (3×3 grid) with a ruler or dial indicator
2. Identify the highest point
3. Set focal height to the highest point — rest will be slightly defocused but consistent
4. Alternatively: add thin shims under low areas

Quick Reference