For years, laser has been viewed as a specialist-only marking solution, with a huge price tag. But thanks to the advancements in technology of the last few decades, laser machines are now fairly cost-effective and can be owned by anyone. That, however, does not make it a wise idea to purchase a laser machine for personal use. Laser marking systems are an outright costly investment if they are not going to be used often. It would be best to hire the services of a laser marking professional if you are going to need it once in a while or on ad hoc basis.
This article looks to give you an understanding of how some of the most common lasers marking systems work and where each can be used.
In carbon migration, heat is applied to a metal causing it to form a chemical bond with carbon molecules. Thanks to this bonding, the carbon properties come to the surface of the metal resulting in a dark, sometimes black, semi-permanent marking.
Carbon migration is one of the fastest laser marking processes as it focuses on relatively small areas at a time with high amounts of heat. That said, it can only be used on carbon-containing materials such as carbide, titanium, stainless steel, and steel.
Annealing is an oxidation process that applies low heat on the surface of a metal to produce a permanent black mark. Unlike carbon migration, the texture of the surface of the metal is not upset, displaced, or moved, so you cannot feel the mark. The process is usually slower as it relies entirely on heat to bring carbon to the metal surface and create the markings. Also, the metal must be allowed to cool down slowly for the best results.
Note that you can achieve a range of colors with annealing, but depending on the type of metal you are marking, and the temperatures reached on the metal surface. Metals suitable for this type of marking include iron, titanium, stainless steel, and steel.
Coloration laser marking
Coloration laser marking is simply the process of colorizing a metal or a plastic using laser technology. Colors are achieved by targeting specific parts of the material with different heat frequencies based on the desired results. It is thus important to know the desired shades beforehand.
When plastic is the material being marked, a foaming process will likely be used. The polymers that make up the plastic can be manipulated to give rise to a vast color wavelength, from ultraviolet to infrared.
Metal coloration, on the other hand, is accomplished through an oxidation process on previously treated and untreated surfaces. This allows more color freedom, making the system suitable for decoration.
Laser machines used for coloration may be considerably expensive, given that they have to operate in a spectrum of frequencies, power levels, and speeds.
Engraving is arguably the most reliable way of creating permanent marking on materials. The laser is targeted on the surface of a material, which it melts and creates bumps on. The process can be repeated on the material as many times as possible to achieve the desired cavity depth.
Laser engraving for metals can be classed into three categories depending on the amount of surface being removed:
- Laser ablation
- Deep laser engraving
This method of laser marking is fast and suitable for materials that will be used in harsh environments.
In etching, the marker eats the surface of metal away by focusing a high-power laser beam on it. The marks created are usually about 0.001 inches deep, but the process can be repeated over and over for deeper cavities.
Materials that can be marked using this process include polymers, ceramics, anodized surfaces, and metal plate surfaces.
Precision is one of the biggest upsides to etching. What’s more, since designs are saved as files, you can engrave identical marks on as many products as possible. Laser etching is thus a suitable option for large scale industrial laser marking.
How to minimize costs when using an online service
Charges for laser engraving metals and other related services depend on how much time the marker takes to finish your design. These tips may help in minimizing the distance travelled by the laser, and hence the time:
- Share cutting lines, if possible.
- Compress your designs. When designs are spread out on the surface of a material, they increase the distance the laser has to travel. Unless it is necessary, consider compressing your designs as much as you can.
- Raster or vector? Vector engraving is a suitable option when the shapes you want to engrave on the surface are large and relatively simple. When the design is too detailed, go for raster engraving. Vector is quicker and more economical overall, but it may not provide the precision needed for detailed designs.
- Make simple designs. Many of the intricate details in your design can be simplified into shapes that the machine can work around quickly and easily without changing the initial design intent. Note that conversion of raster shapes into vectors may include trivial details that the laser may take a lot of time to draw. Most of these minute details are barely noticeable in the marked surface, so review your designs well before marking them on surfaces to cut back on unnecessary expenses.
- Avoid extra hard materials, if necessary – Depending on the purpose of the marking, always make sure to use the softest material possible. Harder materials take longer to mark and thus add to the total cost.
Woods – Both softwoods and hardwoods can be laser marked, but softwoods will need additional treatments to shun burning.
Leather – For leather, avoid laser engraving and raster marking as finished leather can turn powdery.
Plastics – ABS, Delrin, and PEEK are all suitable for laser engraving and laser etching. PETG and styrene have low melting points and are not suitable for engraving.
Metals – Aluminum, brass, steel, stainless steel, and titanium can all be marked using modern laser markers.
Some materials such as ceramics, stone, and glass are better marked using sandblasting or cut using a water jet or diamond.