Monday, June 11, 2018

Laser Cutting in a Material World: Wood

 

Wood Lamp

This is part of series of blogs I will be posting on materials suitable for laser cutting and engraving. We start with the most common material, wood. 

Wood is one of the best materials for a laser cutter. It has relatively inexpensive options and looks fantastic when worked by a laser. Best of all, it is widely available and can be custom sized for your machine.

Wood PropertiesLoren Kerns Forest

Origins: Wood is a natural material derived from trees.

Grain: Different densities and directions of grain can create variations in results.

Growth Rings & Knots: The laser will react differently to knots and other irregularities within the same piece of material. The fewer knots, growth rings, and other blemishes, the better for cutting and engraving results.  

Moisture Content: Dry wood is affected differently by a laser than moist wood.

Oil and Resin Content: Wood with high resin and oil content will tend to edge burn more strikingly.

Some Wood Types

Wood Engrave Koi Fish Project 1-1

Natural Wood  (unprocessed with chemicals)

  • Softwood
    • Pine (first choice for laser cutting)
    • Cedar (soft, straight grain, pleasant smell)
    • Fur (inexpensive but dull look. Best when painted)
    • Redwood (reddish tint, resistant to moisture)
  • Hardwood
    • Ash (hard to find, finishes well)
    • Birch (readily available)
    • Cherry (popular for furniture)
    • Mahogany (works great with lasers, hard to find)
    • Oak (beautiful grain, easy to work with)
    • Walnut (works well with laser, expensive and rare)

Cork (naturally buoyant, elastic and fire resistant)

Balsa (very lightweight, inexpensive, great for laser cutting)

 

Woods Not Recommended For Laser Cutting

Plywood (layered veneer): Ply is heavy in glue which inhibits the laser, when too abundant, keeping the laser from evenly cutting through.

Fiberboard: Fiberboard is made of glued wood fibers, which can inhibit the laser and create poor results as well as noxious fumes.  

Exotic Hardwoods: Extremely dense hardwood can be difficult to cut. Hardwood maple is included here.

Mexican Elder, Oleander: Cutting creates noxious fumes.

Oak, Bamboo (Engraving): Oak and Bamboo are both very fibrous and deep engraving can come out with inconsistent depth due to the back and forth grain density.

For other materials you should avoid with your laser cutter, check out our blog on banned materials. 

Wood Applications

Like these projects? Do them yourself with our free design files.  

Laser Cutting Considerations

Rowmark Hardwood

General Approach: Start with quality wood that is flat and with minimal knots and imperfections. We recommend the Rowmark Hardwood Collection.

Edge Burn: Edge burn is a natural occurrence when the laser vaporizes the wood, it leaves a darkening on the edges. Although edge burn cannot be avoided entirely,drier woods with less resin and oil with produce a lesser edge burn effect.

Thickness: Generally, a 45w CO2 laser can cut up to ¼ “ thick wood, while a 90w can cut up to ½” thick wood.

Density: Wood comes in a wide scale of hardness, which will affect your power and speed settings.

 

Wood Finishing Tips

EdgeBurn

Cleaning

After vector cutting there will be a sooty residue on the edges. Use a rag to gently rub off any excess soot. For rasters, a rag may rub out desired contrast, so wash with a gentle flow of room temperature water and let air dry.

Preserving

A good finish will preserve and protect your piece. Be aware of safety precautions when using finishing chemicals.

Enhancing

Like any wood product, you can stain to enhance wood’s natural beauty. You can also use paint to add color or cover up imperfections in the wood, such as knots.

Laser Settings

Materials Test 1-1

Your power, speed and other laser settings are going to vary depending on things such as thickness and the type of wood you are cutting. Even the wattage of your laser and the local environment can affect settings. Because of this, instead of giving arbitrary settings, we recommend doing a materials test on a piece of scrap wood or in an unused corner of your project material. You can download our Material Test and log book at our Laser 101 website.

 

If you enjoyed this blog, be sure explore our other laser related offerings such as ebooks, video tutorials and our weekly live shows, all free to Full Spectrum Laser owners and operators.