Here, we will be showing you what you need to keep in mind and what to expect when working with wood, as well as how you can constantly improve your processing results.
Seeing as wood is a natural material, you need to consider the various characteristics that come with processing such a product, such as density and resin content.
The more consistent the colour and grain of the wood is, the better the laser engraving results will be.
Suitable Wood Types
|Soft Woods|| |
Soft woods, including balsa or poplar, require a lower laser power level and can be engraved and cut much faster that their harder counterparts. The engraving will, however, be less contrasted - it produces a very light engraving.
|Hard Woods|| |
Harder woods, like oak or cherry, are examples of dense wood that required a much higher laser power level when cutting and engraving. The contrast is start and attractive, unlike softer woods.
|Coniferous Woods|| |
Woods like larch or fir are not really suitable for laser engraving. They usually have very uneven grains, which are also usually very hard and difficult to work with. And then, the wood surrounding the grains is rather soft, making it hard to determine the correct parameters for this kind of wood.
Wood veneers are made up of real wood, so they show the same engraving properties as solid wood panels.
Plywood consists of at least three layers of wood, and the grain is glued and pressed at an angle of 90°. It is available in many different types of wood and thicknesses. It is very important for laser processing - especially for cutting applications. Choose a white-glued plywood panel if you're intending on laser processing it. Or, you can buy some that are specifically designed for lasers. Have a browse of our range here.
|MDF (Medium Density Fiberboard)|| |
MDF is a homogeneous, wood-based material made up of mostly defibrated, bark-free softwood. This is then pressed in longitudinal and transverse directions until it becomes a hardened, workable material. The surface and edges are smooth and firm, so MDF can easily be laser engraved or cut. However, please note that the cutting edges can become very dark during the laser process.
A 'rule of thumb' for laser engraving:
Hard woods = dark engravings. Soft woods = lighter engravings.
A 'rule of thumb' for laser cutting:
The drier and more resin-free the wood = brighter cutting edge.
Wood is a natural material, and it will react differently depending on its type.
Determining the Engraving Parameters
Using the grayscale matrix, you can quickly and easily determine the desired engraving parameters for your product.
Tip: The more you defocus (z-offset, approx. 0.5 - 2mm), the darker the engraving will be. Defocusing the laser will increase its spot size and decrease its performance density. This means it will burn the wood instead of allowing it to pass directly into a gaseous form. This is great for efficiency, but the finer details can be lost.
Determining the Cutting Parameters
You can test the cutting parameters by drawing a simple rectangle with two differently rounded corners. Then, send the graphic to the laser machine. For 3mm thick wood, begin with a high performance and 2-5% cutting speed. Now, you can reach your desired cutting quality by gradually reducing the speed.
Laser Parameters for Download
We have already tested the optimal laser parameters for all types of wood here at Trotec Laser Australia. You can find them all in JobControl, or you can download then here:
The sticky, messy dust that is generated by the laser when engraving wood should never stick to your engraving object - it will very quickly ruin its quality. So, we suggest applying an application tape to the working surface. This will serve as a short-term surface protection measure. After the laser processing is complete, it is simply removed. Application tape is well suited for the engraving of large areas and for cutting. However, please note that it is not suitable for photo-engraving or very fine-line engraving, since this will mean that small parts will then need to be removed later. When selecting your application tape, ensure that your choice is PVC-free and that it is easily removable.
The Correct Optics
Wood laser cutting is a sublimation process. Precise focusing and the right optics are therefore crucial for high-quality results. A distinction must be made between engraving and / or cutting. When engraving, pay close attention to the following: the finer the details, the shorter the focal length of the lens should be! 1.5" or 2" lenses are usually suitable for any wooden laser engraving. But, the situation is different for cutting. The thickness of the material plays a very important role here. The thicker the material, the longer the focal length should be. For 1/8" thick wood, we suggest using a 2" lens, for 1/4" thick, we suggest a 2.5" lens.
The compressed air connection is highly recommended, especially for cutting wood. A small diameter nozzle should be used to protect the lens. Additionally, the small nozzle diameter directs the compressed air straight into the cutting gap made by the laser. This means that dust and gases are removed quickly, and the cutting quality will be significantly improved.
Cleaning the hardware and optics of your laser machine is paramount. Wood dust is very sticky due to the resins and natural oils it contains, and the dust has a bad habit of settling inside the laser machine. So, it is very important to clean the machine regularly, especially if you work with wood on a regular basis.
Suitable Exhaust Systems
When laser engraving and cutting wood, dust and gases are produced. These need to be properly extracted. So, the use of a suitable exhaust system is essential.
Relief Engraving on Wood
Wood is possibly the best material for relief engraving. Here, grayscales are converted into different power levels that can produce three-dimensional looking engravings. You can engrave in several passes with a relatively high performance, and then you just need to run one or two cleaning passes to remove any remaining smoke residue.
Inlays in Wood
Wooden inlays (intarsia) are quite popular with wood. In an inlay, many different woods are laid out flat, so a smooth surface is created. It should then contain many different coloured and structured inlays. Usually, the base material will be engraved first, and then another sheet of material is laid out, cut and inserted. This is usually a veneer of some kind. Please ensure that the width of the laser beam (cutting gap) is adjusted accordingly. This will mean that the carrier needs to be slightly larger.
Did you need some further assistance in finding the perfect laser settings for a specific application? You can always send us your materials and we'll test them out for FREE!