Cutting and engraving wood using a laser machine

Various techniques for processing wood with a laser

Discover a range of techniques you can use in the laser processing of wood materials. Follow on to rediscover how you can achieve best results with mdf, wood veneer and all other wood types.

Wood materials suitable for laser processing

The laser processing of natural wood materials entails taking into account the varied characteristics of the wood materials such as high desity and resin content.

Guideline: The more consistency in the coloring and grain of the wood material, the better the laser engraving result.

Review of suitable wood types

Soft woods	Processing of these varieties of wood materials, such as balsa wood or poplar, call for a lower power level using the laser and can be cut and engraved much quicker. The engraving process produces a lighter outcome.
Hard woods	A more powerful laser power is suggested when laser cutting and engraving hard woods. These varieties of wood, such as oak or maple, are examples of dense woods. The engraving is usually more contrasting than on soft wood.
Coniferous woods	Processing these woods is much more complex than any of the other wood materials. Finding the material parameters is not easy due to the soft texture of the wood surrounding the outside. This therefore implies that these woods, such as larch or fir, are not suitable for laser engraving, mostly due to the high content of hard and uneven grains.
Veneers	Equivalent properties are found within these wood types. Veneered woods are made of real wood and therefore show the same engraving properties as solid wood panels.
Plywood	Plywood consists of at least three layers of wood whose grain is glued and pressed at an angle of 90°. Plywood is sold in various types of wood and is offered in different sizes. When laser cutting, the type of glue is important for laser processing. Select white-glued plywood panels or plywood panels made specifically for laser processing.
MDF (Medium density fiberboard)	MDF is a homogeneous wood-based material made of finely defibrated, mainly bark-free, softwood, which is gently pressed in the longitudinal and transverse directions. The surface and edges are smooth and firm. So MDF can be easily engraved and cut. However, it should be noted that the cutting edges become very dark during laser processing.

Guideline for laser engraving:

Hard woods result in dark, soft woods in lighter, engravings.

Laser cutting guideline:

The drier and more resin-free the wood, the clearer the cutting border.

How to establish engraving and cutting parameters

Woods are natural materials and react differently depending on the type of wood.

How to select the correct engraving parameters

The grayscale matrix feature allows you to promptly and easily determine the desired engraving parameters for your laser machine,

Suggestion: The more you defocus (z-offet: approx. 0.5 - 2 mm), the darker the engraving of the wood will be. Defocussing the laser beam increases the laser spot size, decreases the performance density and burns more wood instead of letting it pass directly into the gaseous form. The disadvantage is that details can be lost.

Determining the cutting parameters

In order to test the cutting parameters, draw a rectangle with two corners being rounded differently. Send this graphic to the laser. For 3mm thick wood, start with high performance and a cutting speed of 2-5%. You can reach the cutting quality you desire by gradually reducing the speed.

Laser parameters for download

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.

Things to keep in mind when laser engraving and laser cutting wood

Material preparation

Wood laser generates a sticky dust which must not stick to the object being engraved. By gluing an application tape onto the working surface, a short-term surface protection is provided. After processing, the tape is simply removed. It is important to note however, that application tape works well for the engraving and cutting of large areas, but it is not suitable for photo-engraving or for very fine engravings, as many small parts will need to be removed. When selecting an application tape, make sure that it is made from a PVC-free material and that it is removable.

The right optics

Laser cutting wood is a sublimation process. Precise focusing and the choice of the right optics are therefore crucial. A distinction must be made between engraving and/or cutting. While engraving, pay attention to the following: The finer the details, the shorter the focal length of the lens should be. As a rule, 1.5" or 2.0" lenses are suitable for almost any laser engraving on wood. It is, however, different for cutting. Here the thickness of the material plays an important role. The thicker the material, the longer the focal length of the lens used. For 1/8 inch thick wood we recommend the use of a 2" lens, for 1/4 inch thick we recommend a 2.5" lens.

Further details of the right choice of lens

Compressed air

The connection of compressed air is recommended for cutting wood. A small-diameter nozzle should be used as this will protect the lens as well as direct the compressed air straight into the cutting gap, which will result in the dust and gas being removed more quickly, and the cutting quality being significantly improved.

Further details of Air assist

Cleaning

Two very important factors in woodworking are the cleaning of the hardware and optics. Because of the resins and oils in wood, the dust is extremely sticky and will easily settle in the machine. It is, therefore, very important to clean the machine regularly.

Further details of laser cleaning

Suitable exhaust system

The use of a good exhaust system to extract the dust and gases which are produced during laser engraving and cutting, is essential.

Further details of exhaust systems

Special applications: Relief engraving and inlays

Relief engraving on wood

When doing relief engraving grayscales are converted into different power levels resulting in a three-dimensional effect. Wood is an ideal material for relief engraving. It can be engraved in several passes with relatively high performance, and then one or two cleaning passes can be performed to remove the smoke residue.

Further tips on relief engraving

Inlays in wood

Wood inlays (intarsia) are particularly popular with wood. To make an inlay, different woods are laid on a flat surface thereby creating a smooth surface which contains different colours and structures to inlay. It is best to first engrave the base material, and then cut and insert the material to be laid (usually veneer). For the veneer, make sure that the width of the laser beam (cutting gap) is adjusted. This means that the carrier must be slightly larger.

Conducting material tests on Trotec laser machines

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