Laser engraving is a process that involves removing material from a surface by vaporizing it using a laser beam. The laser works similarly to a chisel, removing material and creating durable, deep marks. To vaporize the material, the laser strikes localized areas with a large amount of energy, causing high temperatures and vaporization of the material. In this article, you will find detailed information about how laser engraving works and tips on how to find the right machine for this process.
Should you choose laser engraving or laser etching?
If you want to choose the right way of marking using a laser, you should consider three factors:
- the durability of the mark, i.e. its ability to maintain readability under difficult conditions,
- the speed of the marking process, which helps avoid bottlenecks in production,
- the material to be marked and its compatibility with the laser marking method.
Laser engraving technology is often used for engraving metal objects, which are subjected to various types of wear or surface treatment. This process includes 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, which retain high readability even after surface treatment. This treatment can include shot blasting, e-coating and heat treatment, which allows solving the most complex problems related to identifiability. If very durable marking is not required, the laser etching process is usually preferred, which is fast and less ablation-based. 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, which is used for marking stainless steel.
State of matter and laser engraving
The process of laser etching causes the surface of the material to melt and change its roughness, while the process of laser engraving sublimates the surface of the material, creating deep crevices. This means that the surface of the material is heated to such a temperature that it transitions directly from a solid state to a gaseous state, bypassing the liquid state. To achieve sublimation, the laser engraving machine must generate sufficient energy for the material's surface to reach the evaporation temperature within milliseconds. Due to the temperature required for this, laser engravers are very powerful tools.
- Aluminum- 2327°C
- Copper- 2595°C
- Iron- 3000°C
- Lead- 1750°C
- Magnesium- 1110°C
- Zinc- 906°C
It should be remembered that in the case of metal alloys, such as steel, the temperatures needed to reach the boiling point will depend on the composition of the alloy. Upon reaching this temperature, materials transition into a gaseous state. Therefore, when purchasing a laser, it is important that it is equipped with a vapor extraction system, which will protect the work environment, and an air knife, which protects the laser lens. Fiber optic laser systems are particularly beneficial in engraving, as they generate a wavelength that efficiently interacts with metals.
Laser engraving - advantages
Below we present several advantages of laser engraving:
- High precision: Laser engraving is exceptionally precise and allows for the execution of complex patterns with great accuracy. Lasers allow for the creation of very small details, which is difficult or impossible to achieve using other methods.
- Speed and efficiency: this type of operation is fast and efficient, allowing for the processing of a large number of products in a short time. This in turn allows for an increase in the efficiency of the production process.
- Multifunctionality: Lasers are capable of engraving on various materials.
- Quality of finish: Laser engraving allows for very smooth surfaces and sharp edges, providing an excellent aesthetic effect.
- Customization capability: Laser engraving allows for easy changes in designs, enabling product customization according to the customer's 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 damage or scratching the surface.
- Eco-friendliness: Laser engraving is eco-friendly as it minimizes the amount of waste in the production process, thus contributing to environmental protection.
How to engrave high-contrast signs?
By changing the color of the engraved surface, the surface can undergo a chemical reaction with laser radiation, which changes its color, thereby contrasting with the remaining surface. The second method is to change the surface structure. In this way, the laser can produce irregularities on the surface, creating characteristic patterns or textures, which changes the angle of light reflection and thus the contrast. Engraving involves obtaining contrast between the unengraved material and the black marks. This method is fast, but it is only recommended when the raw material has a light color that allows for high contrast. The second method of engraving 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), which allows for the creation of marks in two colors.
How to choose a laser engraving machine?
If you are planning to purchase a laser engraving machine, the list below may help you find the right laser:
- If you want to integrate custom solutions into your production process, you might be interested in OEM marking systems. They offer various types of lasers, including fiber lasers and CO2 lasers, which are suitable for industrial applications. These systems can be integrated by you independently or with the help of an integrator to meet your specific requirements.
- Integrated laser machines are devices that have been designed and equipped in a way that allows their automated or semi-automated operation, enabling easy and quick execution of various tasks using a laser.
- If you have any questions or need assistance, you can always turn to an expert in this field. The expert will help you choose the right laser system, provide advice on the marking process, and answer any questions you may be interested in.
Other laser technologies
In addition to engraving and etching, there are other laser technologies that can be used for marking logos and identifiers, such as barcodes and serial numbers.
CNC Engraving
CNC engraving allows for rapid prototyping, precise engraving, cutting, and deep engraving of machine parts. This technology can be applied to almost all materials, from metals such as aluminum, brass, silver, and titanium, to non-metals such as acrylic, wood, plastics, and foam.
Laser Engraving
It is used for engraving plates on awards, trophies, barcodes/QR codes on machine parts, electronic devices, medical devices, signs, and badges. A high-power laser is capable of making deep engravings on various metals and non-metals.
MOPA Laser
You can also use a MOPA fiber laser to perform colorful laser engravings on metals, such as stainless steel, titanium, and aluminum. Compared to laser engraving, CNC engraving offers greater material flexibility.
CNC Machine Engraving - Advantages
The advantages of engraving using CNC include, among others:
- Precision and repeatability: CNC allows for high-precision and repeatable engraving, which is particularly important for projects requiring accurate dimensions and shapes.
- Speed and efficiency: Engraving using CNC is fast and efficient, enabling the processing of large quantities of products in a short time.
- Multifunctionality: CNC milling machines are capable of engraving on various materials, allowing the application of this technology in many industries, such as advertising, furniture industry, metal industry, jewelry production, and many others.
- Quality of finish: Thanks to precise CNC tools, smooth surfaces and sharp edges can be achieved, providing an excellent aesthetic effect.
- Customization capability: Engraving using CNC allows for easy changes in designs, enabling product customization according to the customer's needs.
- Cost optimization: CNC allows for reducing production costs thanks to precise execution of processes and economical use of raw materials.
- Eco-friendliness: Engraving with CNC is eco-friendly, as it minimizes the amount of waste in the production process, contributing to environmental protection.
All these advantages make engraving with CNC increasingly popular in industry and the production of various items.
CNC Engraving Machine - disadvantages
Although CNC engraving has many advantages, there are certain disadvantages that need to be considered, such as:
- High initial costs: Investing in a CNC milling machine can be expensive and not every company or individual will be able to afford it.
- Required technical knowledge: Operating a CNC machine requires technical knowledge and experience, which can be a barrier for beginner users.
- Necessity of conducting tests: Before the final project is carried out, it is necessary to conduct tests, which can extend the production time and increase costs.
- Size limitations: CNC milling machines have limitations in terms of size and thickness of materials, which can pose a problem for larger projects.
- Risk of material damage: During engraving, the material may get damaged, which can increase production costs or necessitate the need to redo the project.
Why should you choose CNC machines?
CNC machines allow for engraving virtually any material due to the ability to change tools during the process. In the case of laser engraving, it is necessary to choose the appropriate laser for a given material, as one laser cannot be used to engrave many different materials. Therefore, it is important to accurately match the device to the material to be processed. CNC machines offer high precision and repeatability, making them popular in many industries, such as aviation, automotive, defense, healthcare, and the oil and gas industry. However, it should be remembered that due to the constant pressure exerted on the material, there is a risk of it cracking. In addition, typical CNC engravers are not suitable for precise engraving of very fine patterns, which require the use of a very thin drill without the risk of it breaking.