Reducing soot, burn, and char marks on laser cut parts

3 weeks ago
aidan
2 minutes

Laser cutting scorches the material surface along the cut edge and leaves soot deposits from the smoke. There will always be a slight burnt look, no matter how you set up the machine or prepare your material.

Setting Focus

Make sure that you are focusing the laser onto your material properly. All materials are slightly different thicknesses, and more natural materials (like plywood) have greater variation in thickness.

If you change material – even if it’s the same nominal size – do a quick refocus.

Masking Tape

Applying masking tape before cutting protects the surface finish and keeps parts looking clean.

For full sheets, use the large-format masking tape roll from the vinyl craft area to cover the whole sheet in one pass. Smooth it down with a squeegee or roller to avoid air bubbles, particularly over the cutting area, as trapped air can cause inconsistent scorching underneath the bubble. Trim any excess from the edges with a craft knife to ensure the material still sits squarely against the grid.

For smaller parts or one-off jobs, use the 25mm or 50mm wide rolls and cover just the area you need. Run strips edge to edge with a slight overlap so there are no gaps in coverage. This is slower than a full sheet but avoids wasting the wide tape on small jobs.

Make sure that the masking tape is pressed down firmly onto the surface of your material. If there is a small gap or crinkle you may find that the smoke leaks around the edges and still stains the surface.

Engraving

The masking tape will also protect engraved areas from smoke damage. Engraving through tape gives a cleaner result with less surface discolouration around the engraved lines. You will get a cleaner result, but it can end up in masking tape that is a little more fiddly to remove.

Adjusting settings

Each material is different, and even the same material will vary slightly between batches. You can experiment with speeding up, slowing down, or changing the power settings. Ask a technician if you need help with this.