Stone laser engraving: Tips and tricks

By following our tips and tricks you will discover the key areas you need to pay attention to when processing stone, and how to achieve good engraving results.

What types of stone are suitable for laser engraving?

To achieve the best laser processing results it is best to work with polished stone slabs or stones with smooth surfaces. For optimal laser engraving results the stone should have an optimally flat surface to prevent the final engraving being distorted by curves.

Stones with a rounded surface can also be engraved. To do this place the stone on a horizontal plane and use a support, such as modelling clay to hold it. When focusing your laser, use an average value for the engraving area, so that the final engraving result is as uniform as possible.

Discover different stone laser engraving applications.

Tips for purchasing small stones:

Small jewellery stones, worry stones and similar small stones can generally be found in tile departments in hardware stores. Mosaic tiles made from smaller marble stones can be found in many colours, while smaller pebbles can also be used. Remove the glue from the back of the tiles and place them in soapy water. In no time this allows you to get a selection of small stones that are clean, cheap and ideal for laser engraving.

What are the key things to watch out for when stone processing?

Dust is produced when laser engraving stones, which can stick and cause stringing (depending on the type of stone used). It is important to check the nozzle opening prior to (and during for longer jobs) each laser engraving job. The nozzle can become clogged by the dust produced which blocks the laser beam path. Wiping the nozzle with a cloth or rinsing the nozzle with water will restore the optimal performance for your laser machine. The lens and mirror should be checked at intervals during the laser engraving process.

To remove the natural dust layer or dirt from the stone, it is recommended that you clean the stone pre-processing. Rinsing the stone under running water post-processing may wash out part of the stone dust from the laser engraving. This contributes to creating a good contrast between the stones surface and the laser engraving.

Determining laser engraving parameters

There are many advantages for laser engraving stones, however as a natural material stones differ in their geological composition depending on the region. We will show you how to quickly and easily produce good engraving results for your stones easily and quickly.

Variant 1: The grayscale matrix

If you have a flat surface of at least 3×3 cm and sufficient test surface available, we recommend applying the grayscale matrix. You need to engrave with full power with a low engraving speed for hard stones unlike paper or woods. As a starting value, we recommend 100% power (p) and about 30% speed (v) for a laser power of 60 watts, and 100% power and about 15% speed for less than 60 watts. If this setting does not produce the desired results, reduce the speed and run the matrix again. The advantage of this method is that you can assign the exact power settings to each engraved field.

Variant 2: The grayscale gradient

The grayscale gradient is efficient if the engraving area available for testing is very limited. Draw a rectangle with a gradient from 100% black to white. You can use the same printer driver and parameter settings as when using the grayscale matrix method. This is the only method of estimating the suitable power setting. If it is in the middle of the engraved area, the determined power value is 50%. The closer to the black area, the more laser power you have as a result for your setting.

The grayscale gradient has the advantage that it can be applied to even very small areas.

Laser parameters for download

The below list shows the stone types that are, based on our experience, very well suited for laser engraving. These guiding values for achieving good laser engraving results were determined using a Speedy 360, 100 W. Ultimately these will depend on your available laser power, your specific stone and your chosen graphic:

Marble: p50%, v20%, 1000dpi, Z = -0.5mm
Slate: p20%, v100%, 500dpi
Concrete blocks: p100%, v20%, 500dpi
Pebble stones: p80%, v30%, 500dpi, Z = +2
Basalt: p12%, v50%, 500dpi, Z = -1
Agate: p50%, v30%, 1000dpi, Z = +1.5
Bricks: p100%, v30%, 500dpi, Z = +1.5

Bright granite stones can only be laser engraved to a limited degree. You will have to inlay their engravings with colour after the laser engraving process to get a high-contrast result. We explain below how this works.

Ruby®

The parameters are available in the materials list of Ruby®. Missing parameters can easily be imported from the cloud.

JobControl®

You can find them in the JobControl® material database or download them here.

Improving the laser engraving: Tips and tricks

There are certain types of stones which yeild poor or no laser engraving results due to their composition. With a few extra tips and tricks as we explain below, you can get useful results when laser engraving stones.

Change Z-offset value

Changing the Z-value can significantly improve the laser engraving result in many cases. The easy solution to test this is to try offset values of +1 mm and -1 mm and compare the results. For very hard stones, a negative offset value may be the better choice, as this will allow more laser power to enter the processing area.

Inlaying the laser engraving with colour

As previously mentioned some stones do not produce good laser engraving results. By subsequently filling the engravings with acrylic paint (or similar type of paint), you can achieve a high-contrast result. To do this, mask the engraving surface with an application tape, and engrave your desired graphic. Then take acrylic paint and a bristle brush, and dab at the engraved areas with paint. Ensure that the paint has dried and peel off the tape, washing off the remaining, finer tape residue with water.

Better filling results are achieved on smoother or more finely polished stones. Porous or rough surfaces may cause the edges of your artwork to fray, thus not revealing a good contrast.

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