Beam Bench Docs

Focus test

Find the best focal height with a labeled Z sweep on scrap material.

The Focus Test engraves labeled lines at different Z heights so you can compare them and identify the best focus for a specific machine, lens, and material setup.

Automatic Frame and Start require an active GRBL machine profile with Z moves enabled. A machine with manual-only Z control, or a DSP or galvo connection, cannot run the automatic sweep. Use that machine manufacturer's approved manual focus procedure instead.

What you need

  • Scrap from the same material and batch as the job.
  • A connected GRBL machine whose active profile has Z moves enabled.
  • A narrow Z range that the machine manufacturer says is safe.
  • Known-safe engraving speed and power for the scrap.

Steps

1. Open the Focus Test

2. Set the Z range

  • Z min / Z max: bracket the expected focal height with a narrow, known-safe sweep. Confirm the permitted direction and travel with the machine or lens documentation.
  • Samples: the number of intervals between the endpoints, not the number of lines. The test generates Samples + 1 lines; the default value of 9 generates 10 lines.

Do not copy a Z range from another laser. Check the proposed sweep against the machine's available travel and the mounted material before running it.

3. Set engraving parameters

  • Speed and Power: start from manufacturer guidance or a setting already verified on this scrap.
  • Line Length and Step Spacing: size the pattern so every line and label remains on the scrap.
  • Perforated Labels: when enabled, the Z±n.nn label text uses perforated strokes. It does not replace the labels with tick marks.

4. Choose the Z reference

  • Material: treats the values as offsets from the material surface and requires the project's Material Height.
  • Current Z: treats the values as temporary offsets from the head's current Z position.

Confirm which reference matches the machine's normal focusing procedure before moving Z.

5. Preview, frame, and start

  1. Click Preview and confirm the generated geometry fits the intended area.
  2. Secure the scrap, enable ventilation, and follow the machine's eye-protection requirements.
  3. Click Frame to verify the actual position on the scrap.
  4. Click Start and supervise the laser for the entire test.

6. Inspect the result

Compare the labeled lines. For many engraving setups, the narrowest or most sharply defined line indicates the best surface focus, but material response can affect darkness and edge appearance. For cutting, the preferred focal depth depends on the material, lens, thickness, and manufacturer guidance.

Record the Z±n.nn label for the best result. Beam Bench does not store or apply a focus offset from this test automatically.

7. Apply the result through the machine procedure

Set focus using the machine manufacturer's normal procedure. If useful, record the tested value and setup in the machine profile's Notes or in your material records.

Tips

  • If neighboring lines look equally good, repeat with a narrower, known-safe range around them.
  • Recheck focus after changing the lens, material thickness, or mechanical setup.
  • A focus gauge or spacer remains the primary reference when the manufacturer requires one; use this test to verify results on scrap.

Verify it worked

  • The complete pattern stayed on the scrap and within the permitted Z travel.
  • One label or a small neighboring group gives the best result for the intended operation.
  • You recorded the result without assuming Beam Bench changed the machine's stored focus.

On this page

What you needSteps1. Open the Focus Test2. Set the Z range3. Set engraving parameters4. Choose the Z reference5. Preview, frame, and start6. Inspect the result7. Apply the result through the machine procedureTipsVerify it workedRelated