Laser technology has proved to be quite highly useful in the past years, thanks to the ever-growing field of science and technology. With several techniques, methodologies, types of machinery, and applications popping up, one might be confused as to which method of laser technology can be used for what purpose.
Generally, there is a lot of confusion between laser etching and laser engraving. Although there are a few similarities, these two methods are different from one another in a lot of aspects. In this article, we’ll take a look at what laser engraving and etching are, and then we’ll look at where these techniques are employed.
Laser Engraving and Etching – What’s the Difference?
When we talk about the basis on which these techniques are distinguished from one another, it is about how the process affects the surface of the material and how the appearance of the surface is altered. Each process has its unique applications and is employed across several industries.
Engraving differs from etching because it is a process that dogs deeper into the surface, as opposed to etching.
In this process, a beam of laser is used to remove a layer of the surface of the material so that a cavity is exposed. One can find noticeable differences on the surface of the material when it has been engraved. In the cavity, the image of whatever one is trying to engrave is revealed at eye level.
Laser engraving is a form of laser marking, but it still has its own subtleties. It is a quick process that is very easy to employ – instead of creating a raised impression, engraving focuses on vaporizing a flimsy layer of the material. Etching, deep engraving, and ablation are the three types of laser engraving.
Some features of the laser engraving process are listed here:
- Quick and reliable technique, highly recommended for personalizing or customizing parts.
- Deeper markings can be made by employing the technique repeatedly in the desired spot.
- Stands through high wear and tear.
- Can be applied to a wide range of materials.
- Far better and precise than traditional engraving methods.
A type of laser engraving, laser etching occurs when the surface of the material melts due to the heat of the beam. It is regarded as the most efficient process that can be used to permanently mark a variety of materials. The laser’s heat distorts the surface of the material, thus expanding it and creating a texture. Etching is comparatively faster than engraving, considering the fact that it needs less energy.
Etching is usually employed in plated metals, ceramic materials, and thermoplastics. The possible depth of etching is up to 0.025 mm.
- Etching alters the finish of the material which it is worked upon.
- Contrast increases and the reflectivity of the material is changed.
- Due to the expansion of the melted material, a raised marking is formed.
- The typical depth etched is a maximum of 0.001″.
Laser Engraving and Etching – How Does It Take Place?
Laser Engraving and Vaporization
We saw that laser engraving involves vaporizing the surface of a particular material to form a deep mark. How does this occur? Well, the process involves the instant absorption of energy by the surface from the high-energy beam.
With the help of this energy, the change from solid-state to gaseous state takes place efficiently. Also, another notable point is that this change in states takes place without the material ever entering the liquid state. This is called sublimation – the vaporization temperature of the material should be achieved in milliseconds for the process to be successful.
Considering the vaporization temperature of commonly engraved materials, one can conclude that lasers are indeed very powerful. One must know that a laser system will contain a fume extraction system – this is because the vapors will escape as harmful fumes.
Laser Etching – Pulsed Beams
Generally, any laser marking method has one feature in common – in all these processes, the laser beams come out in pulses, as short and sudden bursts of energy, in controlled intervals. Laser etching doesn’t involve vaporization of the material, which automatically means that a comparatively lesser amount of energy is needed for this process.
In other words, one can also say that the energy density that is needed for the process of laser etching is lower than that needed for laser engraving. During the etching process, the surface of the material tends to reflect a considerable amount of energy. The surface will absorb exactly enough energy from the laser beam so that the material’s micro surface attains the liquid state.
As the temperature of the material rises, it becomes malleable. Now, the beam of energy comes out in pulses, which means that the material heats up and cools down within milliseconds. This leads to a localized change in the surface of the material, leading to a new roughness.
Applications of Laser Engraving and Laser Etching
Common applications include:
- Markings on awards and trophies
- Decoration on fine jewelry and accessories
- 2D matrix codes such as barcodes and QR codes
- Identification of medical components
Because it is faster than engraving and has certain advantages, laser etching is employed in various industries.
- In manufacturing, to create contrast marks and permanent markings.
- Creating raised marks on materials that are to be powder coated later. Offers high traceability.
- Permanent marking of heated parts to create a lasting and contrasting impression.
Where and Why – How to Choose the Right Process of Laser Marking
Both laser engraving and laser etching have their own advantages and disadvantages. They also have a wide range of applications, and one must choose the right process for them by deciding on several factors like the type of material, durability, usage, cost, etc. Here is a brief guide which provides you with the basic idea of which process to choose as per your requirements.
Laser engraving is generally used when
- The material you are engraving is steel or aluminum.
- You need deep engraving, a depth of up to 0.5 mm.
- The markings you make need maximum durability.
- Your work involves carving matrix codes that demand unmatchable precision.
- There is laser marking that needs to be done before abrasive treatments.
Laser etching is usually employed when
- The material you are etching is any metal, except stainless steel.
- You want to opt for a faster and more efficient process of laser marking.
- There is some kind of non-abrasive treatment that needs to be done after the marking process.
- There is a need for raised marks that provide considerable contrast.
- You want to go for a cost-effective method.
Why Choose Laser Engraving or Etching?
Both laser engraving and etching prove to be a great alternative for traditional methods because they are faster and more durable.
- The precision of the markings proves to be mighty advantageous.
- The machines used for these processes also require less maintenance and are easy to operate.
- The pulsed beams of power consume low energy.
The above-discussed methods of laser marking are both employed across various industries for numerous applications. Depending on a few important factors, the process employed will be decided. One must ensure to check in with several sources thoroughly before deciding upon a suitable process for them.