What Are the Differences between Laser Marking, Laser Engraving and Laser Etching?
Thanks to industrial and government regulations regarding clearly legible product and part identification, the processes of laser marking, laser etching and laser engraving are increasing in popularity.
All three of these laser services provide a permanent marking solution, fulfilling regulations and adding distinction to your products and parts.
But what sets them apart?
While the three techniques may seem similar, there are actually quite a few differences between them.
The differences between laser marking, laser engraving, and laser etching largely have to do with what each process does to the marking surface, including how deep the laser goes and how it changes the overall appearance.
Laser marking discolours the surface of the material, while laser etching and engraving actually removes a portion of the surface area as it marks. The major difference between laser etching and engraving is the depth to which the laser penetrates the surface.
The Main Differences between Marking, Etching and Engraving
Although these terms are often used interchangeably, there are differences between laser marking, laser etching and laser engraving. Each type of process has its own applications and attributes that make it ideal for different jobs.
The Laser Marking Process
Laser marking is what happens when the beam interacts with the surface of a material, slightly altering its properties or appearance.
- It is achieved by moving a low-powered beam slowly across the material using a method called discoloration, which creates high-contrast marks without disrupting the material.
- Laser heats the material, causing oxidation under the surface and turning the material black.
- It applies low temperatures to metal to anneal the surface.
- All of this is done while leaving the surface intact.
Laser marking differs from laser engraving and laser etching in a number of ways:
- It is less common and not all places offer these services.
- It is also referred to as laser coloration or laser dark marking, as well as charring for plastic materials and annealing for metals.
- There are four common types of laser marking: annealing, carbon migration, foaming and coloration.
- It's popular in the medical device industry for stainless steel and titanium parts, but can be performed on other materials as well.
- A laser marker is ideal for bar codes, UID codes, QR codes, logos and other identification needs.
The Laser Engraving Process
Laser engraving is a process where the laser beam physically removes the surface of the material to expose a cavity that reveals an image at eye level.
- The laser creates high heat during the engraving process, which essentially causes the material to vaporize.
- It's a quick process, as the material is vaporized with each pulse.
- This creates a cavity in the surface that is noticeable to the eye and touch.
- To form deeper marks with the laser engraver, repeat with several passes.
Although engraving is a subsection of laser marking, it still differs in many ways:
- There are three types of laser engraving: etching, deep laser engraving and laser ablation (the difference between the three is what the surface is and how much you remove).
- This is the most common option for people who want something personalized or customized.
- Not ideal for marking safety critical parts.
- Maximum engraving depth is 0.020″ in metals but can go as deep as 0.125″ in materials such as graphite.
- This is the fastest way to mark with a laser.
- It's great for parts expected to experience high wear.
- It's typically used to engrave serial numbers and logos, among other things.
- You can engrave on almost any kind of metal, plastic, wood, leather and glass surface.
Another important comparison to make is how laser engraving compares to traditional engraving:
- It can be done on a number of materials.
- It is more legible than traditional engraving for small objects such as jewellery.
- It provides you with more font options.
- There is a smaller chance of product damage or deformation.
- Laser engraving machines are faster than traditional methods.
The Laser Etching Process
Laser etching, which is a subset of laser engraving, occurs when the heat from the beam causes the surface of the material to melt.
- The laser beam uses high heat to melt the surface of the material.
- The melted material expands and causes a raised mark.
- Unlike with engraving, the depth in etching is typically no more than 0.001”.
The differences between laser etching, marking and engraving include:
- Since a laser etcher changes the surface finish of metals, it alters its reflectivity and enhances contrast.
- It removes 0.001″ or less of the material.
- It can be done on bare, anodized or plated metal surfaces, as well as polymers and ceramics.
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