In this article, we will discuss how to choose the best type of glass for laser engraving, how to create and set up a glass laser engraving design, how to use the laser rotary attachment, and finally learn how to laser engrave glass, produce and finish the final laser engraved glass.
To understand this better, we need to understand how glass laser engraving works. If you are engraving wood with a laser, the laser beam hits the wood and vaporizes it - this is what creates the smoke. However, glass behaves differently. Instead of evaporating the glass, the laser beam hits the glass and causes it to expand rapidly at the point of impact of the laser beam (only 0.1mm wide). The surrounding glass doesn't expand as fast, so the area under the beam breaks. These microcracks are responsible for the formation of engravings on the glass surface.
Depending on the additives in the glass, this process behaves slightly differently, so having several spare parts available for testing before committing is essential.
For example, lead crystals are made by adding lead to glass, which is softer than standard glass and more difficult to engrave successfully because the glass absorbs heat faster, requiring a higher powered laser, which can cause the glass to overheat and shatter .
The best laser engraved glass is actually the cheapest - dollar store beverage glassware laser engraves really well and is an excellent choice to start learning how to laser engrave eyeglasses and get the most out of a laser engraver with a rotary attachment.
How the Laser Rotary Attachment Works
Your Atomstack laser engraver ships with fixed X and Y rails and a fixed laser table area during engraving or cutting. When the laser beam leaves the focusing lens and reaches the workpiece, it has a very small depth of focus (or focus tolerance). This means that the machine itself is ideal for laser engraving on flat surfaces.
How does the Laser Rotary Attachment work?
To overcome these mechanical limitations and engrave on curved surfaces such as glasses and mugs, you can use the Laser Rotation Accessory to rotate the object in a precalculated sequence as the laser fires. This rotation allows the cylindrical workpiece to remain within the focal point of the laser while counteracting the curvature of the workpiece.
There are three main types of laser rotary attachments that you can add to your laser engraver. For my instructions and demonstrations, I will be using a Jaw Chuck style rotary axis attachment.
The Drum Rotation Attachment consists of two long drums that rotate and hold the workpiece in place throughout the engraving process. When the stepper motor turns the roller, the object rotates in the opposite direction. These laser swivel attachments are great for cylindrical objects like water bottles, but anything with a handle can be difficult to get right. For simple cylinders, they are quick and easy to set up. However, they do rely on friction between the rollers and the workpiece, and if they slip, the entire engraved design can become misaligned. This is also why it is not recommended to use the wheel rotation attachment for a second laser scan.
Another type is called the Jaw Chuck Rotary Attachment, which has a set of jaws mounted in a chuck that can be tightened and loosened with a key. Typically, they come with 3 sets of jaws - inner and outer. The interior is designed to expand outward to grip the inside of a hollow item such as a cup or glass. The outer jaws grip the outside of the object. These swivel attachments hold objects firmly so they are more accurate and less slippery.