How Does Laser Etching Work?

Answered on this page:

  • What is a laser?
  • What is laser etching?
  • What is the difference between laser etching and laser engraving?
  • What types of lasers are used for laser etching projects?
  • What are the most common laser etching applications?

Laser technology has found its way into many industries in 2018, and laser etching is certainly one of the most versatile and interesting applications. Laser etching allows manufacturers, artists, and virtually anyone else with access to a laser etching machine and a computer to create their own textual or graphical designs and etch those designs onto a material or object of their choosing.

Laser etching is in use in a variety of industries, and by artists and innovators each day, but how exactly does the laser etching process work?

This article explains the very basics about laser etching. We’ll explain exactly what a laser is, how the laser etching process works and how it differs from the similar laser marking and laser engraving processes, what types of lasers are used, and some of the most common applications for laser etching in the industry today.

What is a Laser?

Lasers are a diverse technology used for many applications, from surgically correcting vision problems to reading discs in a CD or DVD player. The word “laser” is an acronym for “Light Amplification by Stimulated Emission of Radiation”.   A laser is essentially a tool that concentrates light into a beam so powerful that it can manipulate matter. While the flashlights that we are familiar with emit a swath of white light in every direction, lasers emit monochromatic (single color) light, and all of the light is focused into one tiny beam. That little beam is so powerful that it can be used to etch, engrave, and even slice right through certain materials.

What is Laser Etching?

laser etching on silver metal telescope

Laser etching is an industrial process that uses a laser engraving machine to remove material from the surface of an object, leaving a marking in the shape of either a textual or graphical design. In the laser etching process, when the laser contacts the surface of the material, the high heat of the laser causes the surface material to melt. The melted material expands and leaves a slightly raised mark on the surface.

Designs for laser etching are produced in any graphic design software application that supports vector files. Once a design has been created, it can be saved as a vector file and sent to the laser etching machine for “printing”. Laser etching machines use a computer numerically controlled (CNC) router to read vector files and determine how the laser should move to create the required design.

How is Laser Etching Different from Laser Engraving or Laser Marking?

The same laser machines can be used for laser engraving, laser marking, and laser etching, but these processes are not all one and the same. The differences are mainly rooted in how the laser interacts with the chosen material.

Laser Marking – Laser marking is achieved with a low-powered laser beam that moves slowly across the surface of the material. Low-powered lasers are not useful for laser etching or engraving, as they won’t cut into materials of any real durability, but a low-powered laser can be used to heat the material, causing oxidation under the material’s surface and turning it black. Laser marking is useful for creating dark, high-contrast markings on materials like wood and paper.

Laser Engraving – More similar to laser etching than laser marking, the laser engraving process uses a high-powered laser beam to physically remove the surface of a material and create a small cavity on the surface of the material. The process is fast, the material is often totally vaporized by the heat of the laser, and deeper marks are often made by having the laser pass over the same line several times. Laser engraving is effective for marking parts that experience high wear because the deep markings are slow to wear off. Materials are typically engraved to a depth of 0.125-0.020 inches.

Laser Etching – Laser etching is quite similar to laser engraving in that they both use high-powered lasers to mark the material. The main difference is that laser etching causes the surface of the material to melt, and that this process affects the material at a depth that typically does not exceed 0.001 inches. Laser-etched markings are twenty times as shallow as the deepest laser engraving markings. Laser etching is especially effective for creating marks on metal objects, including stainless steel and anodized aluminum.

What Types of Lasers Machines are Used for Laser Etching?

Laser engraving and etching machines are available in two different types: flatbed lasers, sometimes called laser plotters, and galvo lasers. The main difference between laser plotters and galvo systems is the way that the laser beam is applied to the materials from the source. With laser plotters, the beam is directed by a fixed mirror parallel with an X-Y plotter axis system to a focus lens and focused there. The X and Y axis are moved to direct the laser beam to the correct position on the material. The maximum processing area for a laser plotter is defined by the size of the machine, with larger machines allowing a greater area to be etched.

Galvo lasers use high-speed oscillating mirrors to steer the laser beam through a lens. The mirrors are controlled by galvanometer drives and used to direct the laser to the desired location on the material for etching. The speed and efficiency of galvo laser systems allow the laser to mark objects of any geometry at speeds of several feet per second – laser etching with galvo laser systems is very fast!

Both fiber and CO2 laser sources can be used with each type of laser etching system.

What Materials are Needed for Laser Etching?

Chemical etching using acid solutions was a popular means of creating permanent markings on stainless steel and other types of metals before laser etching metal became widely available. This process is relatively cost-effective, but creates waste, as the corrosive acids used in the process must be safely disposed of.

Laser etching requires just the laser etching machine itself, whatever material or object is meant to be engraved, a design and a power source. The success of a laser etching project depends heavily on optimization of the laser parameters to match the properties of the chosen material.

What are the Most Common Applications of Laser Etching?

Lasers are used in many industries, including automotive, industrial and tooling, electronics, medical, military & defense, aerospace, and more.

The most common application of laser etching is to satisfy legal requirements for part traceability set by the government bodies that regulate the industry. For example, medical device manufacturers in the United States are required to ensure traceability of their devices throughout the product lifecycle by marking each device with a unique device identifier (UDI). This could be achieved with a simple alphanumeric code or barcode, laser etched onto the side of the device.

The aerospace and automotive industries are also subject to regulations that require them to adequately mark certain replacement and modification parts. These regulations ensure that if there is an adverse quality event, the manufacturer can easily identify where the parts were sourced and initiate a targeted recall for parts that might be affected.

Conclusion

Laser etching is a versatile application that can be used for art and creativity just as easily as for manufacturing. All it takes to get started is your own computer, free graphic design software, and an idea for something you would love to create – so what are you waiting for?