Laser engraving, laser etching, and laser marking have one main thing in common – they all provide a means of permanently marking a material. Granted, the reasons for the marks will vary ranging from fulfilling statutory obligations in a product life cycle to making artistic pieces for selling on Etsy and other marketplaces. But as similar as these techniques may seem, they are actually quite different.
So what’s the difference between laser engraving, etching, and marking? While laser engraving and laser etching remove some of the material from the surface, laser marking only discolors the surface. The main difference between laser engraving and laser etching is how deep the laser goes on the material.
To help clear out any confusion and to help you determine the best option for your project, let us look at each of these techniques in more detail. But first, here is a table showing the different depths for laser engraving, etching, and marking.
|Laser marking technique||Depth in inches|
|deep laser engraving||deeper than 0.005|
What is laser engraving?
As the name may suggest, laser engraving entails the use of a laser beam to physically remove some material from the surface. This process, therefore, exposes a cavity that reveals an image to the eye. The engraved image can also be felt by hand. The laser beam produces intense heat which causes the material to vaporize. This is usually done pretty fast because the material is vaporized with each pulse. You can achieve a deeper mark by repeating the passes. Laser engraving is viewed as a subset of laser marking but it is the most ideal option for those who are looking to create some personalized or custom items for sentimental or commercial purposes. This is also the fastest way of making a mark with a laser engraver.
Laser engraving is not the best option for marking parts that are safety-critical. Additionally, laser engraving typically has a maximum depth of 0.020” although you can go to a depth of 0.125” in some materials like graphite. Laser engraving gives you a lot of options because you can engrave on quite a number of materials including but not limited to plastic, leather, wood, metal, glass, etc. Apart from engraving personalized and artistic items, laser engraving can also be used to engrave logos and serial numbers on products.
What is laser etching?
Laser etching can be viewed as a subset of laser engraving. In laser etching, heat from the laser beam causes the material to melt at the focal point. This melted material expands thereby causing a raised mark. With etching, the depth cannot exceed 0.001” Unlike marking and engraving, laser etching changes the surface finish of the material and when done correctly, it can help to enhance the contrast. Laser etching is perfect for materials that have more than one layer or iodized aluminum, and coated materials.
What is laser marking?
Laser marking is also referred to as laser coloration, charring or laser dark marking and it is achieved when the laser beam alters the surface of the material. A low-powered beam is required to achieve this slight alteration of the surface. Through laser marking, you can create high contrast marks without damaging the material. When laser marking a plastic surface, you can say you are charring it while annealing is the term commonly used for laser marking metals. There are 4 main types of laser marking;
- Laser Annealing
Laser annealing is usually done on metals like steel, titanium and stainless steel. The surface of the metal is heated with the laser beam which causes oxygen diffusion below the surface. As a consequence, the metal begins to oxidize inside and once it cools off, the oxidation results in a color change.
- Laser Foaming
Laser foaming is the process by which a laser machine heats a polymer resulting in its melting and forming foam-like bubbles. Laser foaming is commonly used in packaging materials as well as in the automotive industry.
- Laser Carbon migration
Carbon migration is an ideal laser marking method for metals and metal alloys. As the name suggests, the laser beam causes carbon to migrate to the surface which causes dark markings.
- Laser Coloration
Laser coloration can be used on both plastics and metals. Specific parts of the material are heated depending on the desired outcome. The pulse frequency and width are modified to achieve different colors and shades. For this reason, lasers that are meant for coloration must have a broad range of power levels, frequencies, and speed.
Laser marking is a common industrial application for marking stainless steel and titanium products but it can still be used on many other materials. A laser marker is also used in identification and branding e.g. UID codes, logos, QR codes, etc.
Where is laser engraving, etching, and marking used?
Various industrial regulations have made it mandatory for industries to use lasers for identification and this has resulted in the wide adaption of these technologies across various industries. For instance, in 2013, the Food and Drug Administration made it mandatory for all manufacturers in the medical industry to include a unique device identifier on all packages and device labels. In aerospace, legislation requires manufacturers to include identification marks on any replacement and medication parts.
Laser engravers were traditionally high-end items costing tens of thousands of dollars and that is why they were initially only applicable for industrial purposes. But the improvement in technology has drastically reduced their prices and it is now possible to get a basic laser engraver for less than $500. The advent of inexpensive laser engravers has made it possible for ordinary people to set up their laser engraving businesses in their garage and some have even acquired them purely as a hobby.