Focus test
Find your machine's true focal point by engraving lines at varying Z heights.
If your machine has Z-axis control, a focus test pinpoints the sharpest focal distance. Run this whenever you change lens, material thickness, or you are not sure focus is right.
What you need
- A piece of scrap material the height of what you actually engrave / cut.
- A machine with Z control (manual or motorized).
- ~10 minutes.
Steps
1. Open the Focus Test
- Menu: Machine → Quality Tests → Focus Test.
- The dialog opens inside the Quality Test Shell.
2. Set the Z range
- Z min / Z max: bracket the expected focal point. For a typical CO2 lens, ±3 mm. For a diode, ±2 mm.
- Samples: 11 (gives 11 lines across the range).
3. Set engraving parameters
- Speed: moderate (~1000 mm/min for diode, ~10 mm/s for CO2).
- Power: enough to engrave visibly but not enough to damage.
- Line Length: 20-30 mm.
- Step Spacing: 3-5 mm (gap between test lines).
- Perforated Labels: on (small tick marks indicate the Z value).
4. Set Z reference mode
- Material: Z values are relative to the material surface. Best if you have a known reference.
- Current Z: Z values are relative to the head's current Z. Easier, just put the head at "approximately right" first, then sweep.
5. Preview, run
Click Preview, verify the pattern fits, then run. The head sweeps through each Z value and engraves a line.
6. Inspect
Look at the resulting lines. The sharpest, darkest line is at the focal point. The Z value of that line is your true focus offset.
- For cutting: focus to roughly the middle of the material thickness.
- For surface engraving: focus on the surface.
- For fine photographic detail: focus exactly on the surface.
7. Apply the focus
If your machine remembers Z position, set Z to the offset you found. If you need to remember it manually, note the Z height in the machine profile's notes.
Tips
- A 10-line sweep at ±5 mm gives coarse results fast. Follow with a ±1 mm sweep at the new midpoint for precise focus.
- Materials with different reflectivity show different "sharpest" lines. Run a focus test per material if your work spans several.
- If your machine has a focus gauge / spacer, use the test to verify the gauge's accuracy.
Verify it worked
- One line is clearly sharper than its neighbors.
- After applying the new focus, a subsequent material test gives cleaner results.
Related
- Focus Test dialog
- Focus and depth of field explainer
- Material test grid: run after focus test
- Quality Test Shell