We've just started a new blog to try to keep people informed about life at Cutting TechnologiesTechnical Information - Laser Engraving / Etching
Laser Engraving (or Laser Etching) is a surface technology. The laser interacts with different types of material in different ways:-
For Organic Materials such as Wood the laser burns the surface of the material, almost like a very accurate branding iron. The depth can be varied and 3D effects can be created.
For Polymers such as Acrylic the laser vapourises part of the surface, changing its appearance. 3D effects can be created, but not as successfully as with Organic Materials.
For Natural Materials such as Granite and Stone the laser actually causes tiny fractures in the surface, and this results in a textural and contrast difference with the surrounding material. We can only do 2D engraving with these materials.
For Metals the normal method of marking is to apply a paste which the laser bakes into the surface, giving a black mark on the metal. Coated metals are different - for example with painted brass we remove the paint, with anodised aluminium we change the colour of the anodised surface.
Laser Engraving can work in two different ways - we can Raster Engrave or Vector Engrave.
Raster Engraving uses a raster-based image such as a JPG and the laser treats this as one big piece of Art. To recreate this image the laser scans back and forth over the material and fires the power proportionate to the depth of greyscale in the image - black areas receive maximum laser power, white areas do not get engraved, the shades between the two get a varying amount of laser power. This allows us to create photographic images and 3D effects up to a resolution of around 600dpi. Raster Engraving is currently only possible on our smaller lasers, so the maximum work area is 900x600mm.
Vector Engraving is very different - it uses a vector-based file such as an Illustrator or Autocad file and the laser in effect follows the lines. The laser power is not variable, it switches on at the start of the line and switches off at the end. The only difference between Vector Laser Engraving and Laser Cutting is power - if we set the laser power too high when engraving we'll cut the material; if we set the power too low when cutting we'll engrave! We can Vector Engrave certain materials up to 3000x1500mm work area, as our large industrial lasers can be tuned to do this.
Please note - if you want Technical information about our Laser Cutting Service please see the Laser Cutting Section