There are two types of Laser engraving. Light engraving is where a relatively shallow trench is created, between 5µm and 25µm. The depth achievable depends on the material, and also the power and the dwell time of the Laser. Deep engraving is used for making moulds and dies, stamps, etc. The depth that can be achieved is entirely dependent on how the material absorbs the Laser, how much energy the Laser has, and how long the Laser can dwell on the target. Deep engraving is usually a fairly slow process.
Both types of engraving can be carried out on surfaces such as different metals and some plastics. Engraving can be used to make marks, for example identification numbers, and logos and can also engrave complex images created in graphics packages.
Lasers have many advantages over older technologies such as machining. The main advantage is that there is no contact between machine parts which means there is no tool wear. Lasers also offer greater precision and can engrave more complex patterns and images.
Fiber Lasers are a relatively new technology that have shown very promising results in the field of Laser engraving. Compared to other types of Lasers, they can offer better quality in marking and deep-engraving thanks to short pulse duration minimising thermal effects and faster speed processing with high peak power pulses.
Engraving is the most common of all Laser marking applications, the engraving process is produced by the Laser beam removing material to create a mark, where the Laser acts like a chisel and blows away selected areas of the subject material.
Engraving is the art of carving a design into a hard surface. Typically its done by hand, using an assortment of hand engraving tools:
This is a laborious and difficult to learn process. Fortunately, CNC machines are capable of very sophisticated engraving.
Sometimes CNC engraving is purely utilitarian, for example to add a serial number to a part. Other times it is an artistic embellishment. The type of CNC Engraving Machine you have will determine most of what's needed to engrave.
Many materials can be cnc engraved by laser including:
Wood: The laser carbonizes or burns many natural materials like wood and leather.
Metals: Metal requires a lot more power and sometimes specific laser types that operate a frequencies that work more efficiently with metal.
Coated Materials: Sometimes it's easier to engrave with a laser that burns away or discolours a particular coating. There are specialty coatings made for exactly this purpose.