Laser Etching: Definition, How It Works, and Process
Learn more about this manufacturing process and its different applications.
Laser etching is the process of creating patterns and designs on a material by altering its surface with a laser. While the term laser etching is often used interchangeably with the terms laser engraving and laser marking, there are definite differences among the processes. This article will describe laser etching, how it works, its laser settings, and the materials that can be laser etched.
Laser etching is the process of altering the surface of a material to create marks for informative or aesthetic purposes. As the surface of the material alters, it expands and cools to form the desired mark. This process results in a slightly discolored, depressed mark and a raised surface along the edges of the mark. Laser etching is a highly versatile process used on organic materials such as wood and leather, synthetic organics (plastics), and inorganic materials like metals. Different types of lasers, including CO2, fiber, crystal, and diode lasers, can be used for etching. From personalized gifts and decor to laser etching to parts with barcodes, QR codes, and serial numbers for product traceability, there are many uses of laser etching.
Despite the fact that lasers were invented back in 1964, the laser etching process was not developed until 1978. Between 1964 and 1978, lasers were primarily used for welding and cutting. No one can say for sure who created the laser etching process but its creation has enabled hobbyists, small businesses, and large manufacturers alike to leverage its capabilities and benefits.
Laser etching melts or alters the surface of a material to create raised marks. Laser etching is typically done with a pulsed laser as opposed to a continuous wave laser. This is because continuous wave lasers are not as efficient at laser etching. A pulsed laser delivers powerful bursts of energy at set intervals to the material. For instance, a 100W laser can be pulsed to deliver 100,000 pulses in one second. If it were continuously fired, it would consistently deliver 100 J of energy in one second but because it is pulsed, it can deliver 10,000 J of energy. This is the principle behind laser etching. Pulsing the laser allows the amount of energy that can be absorbed in a short time to be dramatically increased. This is similar to trying to wash a car with a gentle stream from a hose as opposed to short, powerful bursts. While some energy is reflected, much of the energy is converted to heat and causes the material to rapidly increase in temperature, melt, and expand.
The laser power required to laser etch depends on the particular material and its melting point or the temperature at which it begins to decompose into constituent materials. Some materials, like wood, do not melt but rather decompose into charcoal and carbon dioxide, among other things. Other materials, like plastics and metals, melt into a liquid state. For instance, laser etching steel requires higher power than wood does.
Laser etching offers a fast, infinitely customizable, non-contact method for creating both artwork and practical product features, such as identification marks. In the aerospace, automotive, and medical industries, laser etching marks parts with serial numbers, barcodes, and QR codes. These markings contain vital information that tracks the source of a particular product throughout its entire life cycle. Laser etching can help manufacturers to ensure the safety and durability of their products for end users by allowing them to trace every part, enabling them to quickly institute recalls and make design or process changes if a product is defective.
There are many applications of laser etching. Some examples are listed below:
- Personalized gifts, trinkets, and jewelry made of paper, wood, glass, precious metals, and other materials
- DIY decor
- Brand symbols such as logos, slogans, and motifs
- Traceability and identification features, including barcodes, QR codes, and serial numbers.
The procedure for the laser etching process is described below:
- Prepare the Design: Convert the desired image or pattern to be etched into a format that can be read by the laser etching machine. This file is usually in .dxf format or a similar vector-based format.
- Establish Laser Etching Settings: Configure the laser machine settings for the best etching quality. Settings will differ based on the particular material being etched.
- Secure the Workpiece: Fix the position of the workpiece using tape, adhesive (such as a glue stick), or clamps to ensure it does not move during laser etching.
- Prioritize Safety: Wear protective eyewear and ensure that sufficient ventilation is present to remove fumes that can contaminate the work area.
- Laser Etch the Part: Some laser machines will auto-focus the lens, but others may need the lens to be manually focused. Once the laser is focused and the aforementioned steps are completed, begin laser etching the part.
Laser etching is used on a wide range of materials, including: metals, organic materials, plastics, and ceramics. Many metals may need to be coated with a metal marking spray or paste to reduce reflectivity and enhance the material’s absorption of laser radiation. Some examples of metals that can be laser etched are described in the list below:
It is easy to laser etch magnesium due to its relatively low melting point (1215°F) compared to other metals. Laser etching magnesium and its alloys have low reflectivity and therefore do not need to be pretreated.
Aluminum’s relatively low melting point (1216°F) compared with other metals makes it easy to laser etch. Its widespread use in several industries makes aluminum one of the most common metals for laser etching.
Zinc’s exceptionally low melting point (786°F) makes it easy to laser etch. Zinc and its alloys are commonly used in diecast parts and automotive components. Laser etching can efficiently produce high-contrast and permanent marks such as barcodes on zinc parts.
Lead is another metal that is easy to laser etch because of its low melting point (621°F). Laser etching lead can result in surfaces displaying different shades of black, white, and gray. This makes traceability easy for lead parts.
Steel is a commonly used material for laser etching considering its widespread use across several industries. The degree of difficulty for laser etching steel largely depends on the type of steel alloy and its chemical composition. Steel requires more powerful lasers compared to the other metals on this list due to its higher melting point (2370-2800°F).
The melting point of anodized aluminum is the same as that of naturally oxidized aluminum. The primary difference between the two materials is that anodized aluminum has a thin layer (between 0.002-0.07 mm) of aluminum oxide on its surface that protects it against corrosion and abrasion. This makes laser etching ideal for anodized aluminum as it does not affect the material’s passivation layer.
Caution is advised when laser etching stainless steel. The outer protective coating that makes it resistant to corrosion is removed by the laser etching process. While the material can be etched, its appearance and performance can be affected. Consequently, laser annealing is more commonly used to mark stainless steel.
Laserable brass is a special type of brass that is coated with lacquer or enamel. This material assists the metal in absorbing laser radiation since bare brass is typically highly reflective.
A wide variety of materials are used in laser etching. Some of them are listed below:
- Medium-density fibreboard (MDF)
- Paper and cardstock
Several materials should not be laser etched, including:
- Polyvinyl chloride (PVC)
- Polyvinyl-butyral (PVB)
- PTFE or Teflon™
- Beryllium oxide
- Any material containing halogen elements
The advantages of laser etching are listed below:
- Produces superior quality marks compared to traditional methods that use acids or abrasion
- A faster process compared to traditional marking methods
- Can be used on a wide variety of materials
- Is a non-contact process that doesn’t introduce mechanical stresses into the part or cause chemical reactions
The disadvantages of laser etching are listed below:
- Marks made by laser etching wear out and become distorted if in an abrasive environment
- Upfront costs for laser etching machines can be high for smaller operations
The best laser etching machines depend on the application requirement. Listed below are some recommended laser etching machines:
- OMTech 50W: This might be the best overall laser etching machine. At $5,300, this fiber laser is capable of etching any material —from wood and paper to metals and plastics. It offers exceptionally precise cuts with tolerances of +0.0001 mm that are made at incredible speeds of up to 275 in/sec.
- Atomstack X7 Pro: This 10W diode laser costs $570. It offers a great balance between economy and capability for both beginners and professionals. This laser etching system has a work area of 16.14" x 15.75" and a spot size of 0.002" x 0.002". The X7 Pro has an etching accuracy of around +0.003”.
- Ortur Laser Engraver, Laser Master 2 S2 SF: This is a 1.6W diode laser system and costs $233. It can be considered the best system for beginners because it is inexpensive, but can still etch materials ranging from wood to metals. However, it is not as precise as the other two machines mentioned. It has an etching accuracy of only +0.0125 mm.
Laser etching machines are primarily sold online and are available either directly from manufacturers or through e-commerce sites such as Amazon and Walmart.
A laser etching machine can cost anywhere from $300 to $500,000. The cost largely depends on the type of laser and the equipment and materials used to manufacture the system.
Laser etchers can last up to 10 years, depending on the type of laser, the quality of the materials that comprise the system, how often the machine is used, the materials that are most often etched, and how well the machine is maintained throughout its life.
Yes, laser etching wears over time because laser etchings are raised from the surface of the part. This makes it more susceptible to wear and distortion.
Yes, laser etching can be a highly profitable business. There is high demand for laser etching for crafts, decor, and numerous other applications. Additionally, laser etching is easy to learn and has a low cost of entry.
No, laser etching is not difficult to learn. With plenty of low-cost machines and tutorials available online, anyone can master the basics and quickly get started with laser etching.
Yes, glass can be laser etched. Laser etching glass melts and deforms the surface, causing the metals (such as metallic oxides used for coloring or strengthening the glass) and silica in the glass to react with the air. This causes tiny fractures that can be seen and felt.
No, laser engraving is not the same as laser etching. Laser engraving requires more laser power and vaporizes material away to create shallow cuts into a part. Laser etching requires less power and only melts material at its surface. For more information, see our guide on Laser Engraving.
The primary difference between laser engraving and laser etching is that laser engraving makes cuts deeper into the part than laser etching does. Additionally, while laser etching melts or alters material at the surface, laser engraving vaporizes material away. For more information, see our guide on Laser Engraving vs Laser Etching.
This article presented laser etching, explained what it is, and discussed the process and method in detail. To learn more about laser etching, contact a Xometry representative.
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