Laser engraving is a process that removes material from a surface by vaporizing it using a laser beam. The laser works similarly to a chisel, drawing material and creating permanent, deep marks. To vapourize the material, the laser hits the localized areas with high energy, resulting in high temperatures and vaporization. In this article, you will find detailed information on how laser engraving works and tips on finding a suitable machine.
Should you choose laser engraving or laser etching?
If you want to choose the correct laser marking method, you should consider three factors:
- the robustness of the mark, i.e., its ability to remain legible under challenging conditions,
- the speed of the marking process, which helps avoid production bottlenecks,
- the material to be marked and its compatibility with the laser marking method.
Laser engraving technology often engraves metal objects subjected to various wear or surface treatments. This process covers metals such as steel and aluminum, including anodized and die-cast aluminum. One of the most distinctive features of laser engraving is its ability to engrave 2D codes that remain highly legible even after surface treatment. This treatment can include shot-blasting, e-coating, and heat treatment to solve the most complex traceability problems. If very robust marking is not required, the laser etching process, which is fast and less ablation-based, is usually preferred. This method can be applied to a wider range of materials, including:
- steel,
- aluminum,
- anodized aluminum,
- lead,
- magnesium,
- zinc.
There is also a unique method of marking metals, called laser annealing, used to mark stainless steel.
State of aggregation and laser engraving
The laser etching process melts the material's surface and changes its roughness, while the laser engraving process sublimates the material's surface, creating deep fissures. This means that the material's surface is heated to such a temperature that it goes directly from a solid state to a gaseous state, bypassing the liquid state. To achieve sublimation, the laser engraving machine must generate enough energy for the material's surface to reach its evaporation temperature within milliseconds. Because of the temperature required for this, laser engraving machines are practical tools.
- Aluminum- 2327°C
- Copper- 2595°C
- Iron- 3000°C
- Lead- 1750°C
- Magnesium- 1110°C
- Zinc- 906°C
It is important to note that for metal alloys, such as steel, the temperatures needed to reach the steaming point will depend on the composition of the alloy. When this temperature is reached, the materials change to a gaseous state. Therefore, when purchasing a laser, it is essential that it is equipped with a vapor extraction system to protect the working environment and an air knife to protect the laser lens. Fibre laser systems are particularly beneficial in engraving, as they generate wavelengths that interact efficiently with metals.
Laser engraving - advantages
Here are some of the advantages of laser engraving:
- High precision: Laser engraving is exact and allows complex designs to be made with a high degree of accuracy. Lasers allow very small details to be made, which is difficult or impossible to achieve with other methods.
- Speed and efficiency: this type of operation is fast and efficient, making it possible to process a large number of products quickly. This, in turn, makes the production process more efficient.
- Multifunctionality: lasers can perform engraving on a variety of materials.
- Quality of finish: Laser engraving produces smooth surfaces and a sharp edge, resulting in an excellent aesthetic effect.
- Personalization Capability: Laser engraving makes it easy to make design changes, allowing products to be personalized according to customer needs.
- No contact with the material: The laser removes material directly from the surface, avoiding physical contact with the material and minimizing the risk of damaging or scratching the surface.
- Eco-friendliness: laser engraving is environmentally friendly as it minimizes waste in the production process, contributing to environmental protection.
How do you engrave high-contrast signs?
By changing the color of the engraved surface, the surface can undergo a chemical reaction with the laser radiation, which changes its color and thus contrasts with the rest of the surface. The second way is to change the structure of the character. In this way, the laser can produce irregularities on the surface, creating distinctive patterns or textures, which change the angle of reflection and, thus, the contrast. Engraving involves creating a contrast between the unengraved material and the black marks. This method is fast but is only recommended if the raw material is light in color to achieve high contrast. The second engraving method is more time-consuming but allows for higher-quality contrasts. During this method, the laser system uses both laser engraving (to create black marks) and laser etching (to create white marks) to make marks in two colors.
How to choose a laser engraving machine?
If you are planning to purchase a laser engraving machine, the following list can help you find the right laser:
- If you want to integrate custom solutions into your production process, you may be interested in OEM marking systems. They offer different types of lasers, including fiber and CO2 lasers, suitable for industrial applications. These systems can be integrated by you alone or with the help of an integrator to meet your specific requirements.
- Integrated laser machines are designed and equipped to be automated or semi-automated, allowing you to perform various laser tasks easily and quickly.
- If you have any questions or need help, you can always contact an expert in this field. An expert will help you choose the right laser system, advise you on the marking process and answer any questions.
Other laser technologies
In addition to engraving and etching, other laser technologies can be used to mark logos and identifiers, such as barcodes and serial numbers.
CNC engraving
CNC engraving enables rapid prototyping, precision engraving, cutting, and deep engraving of machine parts. This technology can be used on almost any material, from metals such as aluminum, brass, silver, and titanium, to non-metals such as acrylic, wood, plastic, and foam.
Laser engraving
It is used for engraving plaques on awards, trophies, barcodes/QR codes on machine parts, electronic devices, medical devices, signs, and badges. The high-powered laser is capable of making deep engravings on a variety of metals and non-metals.
MOPA laser
A MOPA fiber laser can also produce color laser engravings on metals such as stainless steel, titanium, and aluminum. Compared to laser engraving, CNC engraving offers greater material flexibility.
Engraving with a CNC machine - Advantages
The advantages of CNC engraving include the following:
- Precision and repeatability: CNC enables high-precision and repeatable engraving, which is particularly important for projects that require precise dimensions and shapes.
- Speed and efficiency: CNC engraving is fast and efficient, making it possible to process large quantities of products quickly.
- Multifunctionality: CNC milling machines are able to perform engraving on a variety of materials, allowing the technology to be used in a wide range of industries, such as advertising, the furniture industry, the metal industry, jewelry manufacturing, and many others.
- Quality finish: Using precision CNC tools, smooth surfaces, and sharp edges can be achieved, resulting in an excellent aesthetic effect.
- Customisability: CNC engraving makes it easy to make changes to designs, allowing products to be personalized according to customer needs.
- Cost optimization: CNC allows production costs to be reduced due to the precise execution of processes and the economical use of raw materials.
- Eco-friendliness: CNC engraving is environmentally friendly as it minimizes production waste, contributing to environmental protection.
All these advantages make CNC engraving increasingly popular in the industry and the production of various items.
Engraving with a CNC machine - disadvantages
Although CNC engraving has many advantages, there are some disadvantages to consider, such as:
- High initial costs: Investing in a CNC milling machine can be expensive, and not every company or individual can buy one.
- Technical knowledge required: Operating a CNC machine requires specialized knowledge and experience, which can be a barrier for novice users.
- Testing required: Before a final design is made, testing is required, which can increase production time and costs.
- Size limitations: CNC milling machines have limitations on the size and thickness of materials, which can be a problem for larger projects.
- Risk of material damage: Damage to the material can occur during engraving, which can increase production costs or result in having to redo the design.
Why choose CNC machines?
CNC machines allow you to engrave virtually any material thanks to the ability to change tools during the process. With laser engraving, it is necessary to choose the suitable laser for the material, as one laser cannot be used to engrave many different materials. It is, therefore, essential to match the machine precisely to the machining material. CNC machines offer high precision and repeatability, making them popular in many industries, such as aerospace, automotive, defense, healthcare, and oil and gas. However, it is essential to note that there is a risk of breakage due to the constant pressure exerted on the material. In addition, typical CNC engraving machines are not suitable for the precise engraving of beautiful patterns, which require a skinny drill bit without the risk of breakage.