Beam Bench Docs

Cut acrylic with kerf compensation

Measure the kerf, then create and verify explicit offset geometry for accurate acrylic parts.

When acrylic parts need to fit precisely (press-fit assemblies, snap-fits, gears), you have to account for the material removed by the laser beam.

Beam Bench stores and displays the per-layer Kerf value, but the current planner does not apply that value to generated job paths. Do not rely on the layer field to resize an outline or hole. Create explicit offset geometry and verify it on scrap instead.

What you need

  • Cast acrylic in the thickness you want to cut.
  • Calipers.
  • A test cut you have already verified for power and speed (see Material Test if you have not dialed in your settings).

Steps

1. Cut an uncompensated test square

Draw a 50 × 50 mm square. This is a metric reference size; if the current Display Unit is not millimeters, convert both dimensions to the unit shown before entering them. Set the layer to Line mode at your validated cut settings, then cut it from scrap.

2. Measure the result

Use calipers. The actual part should be slightly smaller than 50 mm in each direction. Note the difference and call it total kerf loss.

The kerf radius is half the total loss. For a 50 × 50 mm design that came out at 49.8 × 49.8 mm:

  • Total kerf loss = 0.2 mm.
  • Kerf radius = 0.1 mm.

Treat the measured radius as a starting value for that exact machine, material, thickness, focus, and cut setting.

3. Measure an interior opening

Cut an uncompensated 20 × 20 mm hole in scrap and measure it. This is also a metric reference size; convert both dimensions to the current Display Unit before entering them. Record how much larger the hole is than the design. Comparing the part and hole measurements helps you confirm the offset before making real parts.

4. Create explicit offset geometry

Keep the original geometry until the compensated result is verified:

  • Select an exterior part contour.
  • Choose Tools → Offset Shapes (Alt+O).
  • Set Direction: Outward and Distance: the measured kerf radius.
  • Leave Delete Original off and apply the offset.
  • For an interior opening, select its contour and repeat with Direction: Inward.

The Distance label and entered value follow the current Display Unit. Convert the measured radius to the unit shown before entering it; Beam Bench stores the geometry internally in millimeters.

Use the dialog's live preview to confirm the direction. Before generating a job, make sure only the intended compensated paths are assigned to output. Keep the original paths on a non-output layer or remove them only after you have verified the result.

5. Verify on scrap

Preview and cut the compensated part and opening on scrap. Measure both with calipers and check the fit. If either dimension is wrong, adjust the offset and repeat the scrap test.

Do not cut the real parts until the compensated scrap result matches the intended dimensions and fit.

6. Cut the real parts

Frame, preview, and cut only after the scrap verification succeeds. Measure a finished part before producing the rest of the set.

Current per-layer Kerf status

The per-layer Kerf setting can be saved with the project, but it does not currently change the planned paths, Preview, or generated G-code. This page will be updated when planner support is implemented and validated.

When kerf does not matter

  • Engraving fills.
  • Decorative cuts where exact fit is not required.
  • Single shapes that do not interface with other shapes.

On this page

What you needSteps1. Cut an uncompensated test square2. Measure the result3. Measure an interior opening4. Create explicit offset geometry5. Verify on scrap6. Cut the real partsCurrent per-layer Kerf statusWhen kerf does not matterRelated