How Does Laser Engraving Work?

Alyssa Mertes

Alyssa Mertes

Promo Expert

Published: April 22nd, 2019

Who doesn’t enjoy reading about laser beams? Sci-Fi fans, eye-surgery patients, and light show enthusiasts far and wide are eager to hear all about the world of beaming light! Lasers represent a fascinating intro to the world of optical sciences – and we’re about to learn how they relate to promotional items!

Lasers: they're not just for your epic tales of science-fiction adventure. Thanks to applications and tools used in the medical, manufacturing, and even retail industries (hello, barcode scanners!), lasers figure into everyday life right here on Planet Earth.

What Are Lasers?

So how does it work, and why does it produce different color imprints on different items?

Let's find out!

The word laser is an acronym. It's short for Light Amplification by Stimulated Emission of Radiation. We know; some of you wanted to fall asleep as soon as you read that phrase, while others are probably thankful you can refer to it simply as a "laser".

Stay with us here! We won't get too technical, but here's a really basic summary of the way laser equipment works:

The equipment is hooked up to a source of energy, like electricity.

The energy passes through a specialized material inside (more on that soon) and gets the material's atoms all excited, as if they've had too much caffeine.

The atoms discharge that extra energy in the form of bits of light called photons.

Mirrors inside of the equipment focus the photons and produce a concentrated beam of light –your laser beam!

The energy from that light gets converted to heat energy, so using a laser to decorate an item essentially burns the item’s surface (very, very carefully!). A computer calibrates the temperature of the laser beam and the area it covers so it decorates only the spot specified on your promotional item.

Bullet points are great for summarizing how things work, but you know what’s even better? A video. Take a look below to see what happens when promotional products get laser engraved!

What about those special materials?

Not every laser engraving machine uses the same chemical or compound inside to produce a laser beam. The two types of lasers we read about most when it comes to decorating your promotional products are CO2 lasers and Nd:YAG lasers.

CO2 lasers contain chambers that are filled with carbon dioxide gas. They're low-energy machines that are great for engraving materials like wood, glass, lightweight plastics, and even fabric.

Nd:YAG lasers contain a solid material called neodymium-doped yttrium aluminum garnet. Nd:YAG lasers are high-energy lasers that are used on denser materials, like metals and high-grade plastics (but never PVC or other plastics that contain chlorine, because those release a toxic gas when exposed to laser energy, and no one wants that).

So how do lasers create a design?

To engrave an item, manufacturers use machines that are set so that the laser isn't strong enough to cut all the way through the material. The laser beam pulses extremely quickly and burns away bits of material from the item's surface, leaving a slight impression or, in the case of fabrics, a light surface burn.

And how does the laser know where to go to create your design? With the help of computers, of course! Design software translates your graphic files into a pattern the laser engraving machine can transfer onto your mug or pen. Laser engraving machines can use raster images (which are recommended for copying photos onto items) or vector images (which are ideal for line-heavy art that needs to be resized).

How Does Laser Engraving Produce Color? Why does engraving create certain colors on certain items?

The color (or absence of color) that results from laser engraving has a lot to do with the material the item is made of and the way it reacts chemically to high-energy laser light. Usually, as the video above explains, laser engraving doesn’t produce a color, because it’s just burning and stripping away layers of the item material.

But there are exceptions, especially in the cases of certain metals. Aluminum, for example, often oxidizes and turns white when it's engraved, while other metals don't change color at all.

Also, if your item is made with a painted metal or a wood that's been covered with a veneer, engraving it will reveal the color of the metal or wood underneath the paint or veneer. It's like stripping away the layers of an onion, except that it won't make anyone cry (assuming everyone's following proper safety procedures while they engrave.)

These days, some manufacturers use other techniques to add color to an engraved logo. Foils and powdered dyes are available to spread over an engraving – another pass beneath the laser will make them a permanent part of the decoration!

With so many options available for customization, laser engraved promotional products offer plenty of elegant-looking options. Who could’ve imagined that the power of light energy could be combined with computer software and manufacturing equipment to create amazing-looking promotional gifts? So the next time you want an out-of-this-world look for your logo, consider an item that's laser engraved!