This is part of a series of blogs for laser cutting and engraving materials. This time we look at glass.
While a laser can't cut glass, it can etch and mark it with impressive results. The laser creates micro-cracks in the glass, creating a white "matte" appearance on the engraving, which is rich and clean in detail.
Glass is mainly derived from silica (sand) along with a few other minerals that fuse together to form glass with different colors and properties.
The way the laser reacts to glass is very different from most other materials, because the laser does not remove the material, but produces a thermal reaction that causes the material to expand into micro-cracks on the glass surface.
Many types of glass use metals (such as leaded crystal). These metals cause the laser to fail to mark glass at all. For a laser cutter, cheaper plain glass (soda ash glass) works best. This includes most consumer glass, such as your regular bottle or glassware.
The most common types of glass, which account for nearly 90% of consumer glass products, include:
Also known as flat glass or flat glass, it is often used in windows.
Ideal for laser marking, glassware including drinking glasses, beer glasses, wine glasses, etc.
The process of pressing molten glass into a mold.
Lead-containing crystal glass or other high-end glass containing heavy metals
Etched glass turns ordinary glassware into special displays that can commemorate any occasion. Add logos, names, promotions, celebration dates, graphics and custom designs to glassware, bottles, jar mirrors and more.
Glass behaves differently than other materials, and each piece of glass may respond slightly differently to the laser.
CO2 lasers do not cut glass. Don't even try.
Bottles and glasses are popular items for laser engraving, but their roundness can cause uneven focus. For these, risers and swivel attachments are ideal because they keep the laser focused on one length throughout the job.
The power setting on the test glass is critical because the results are sensitive and have a smaller window of success than common materials. Most of the glass work is the power setting. You want the most frosted look, with no micro-cracks coming off the main glass.
Can you feel the small pieces of glass come off as your fingers move over the etching? Try lowering the power setting to reduce flaking.
Regardless of your power settings, laser-etched glass will never be as clean as the other two most common etching methods (acid etching and sandblasting). However, having a laser is still essential for other types of etching if you want precise designs. If you are using an acid etch or sandblaster, using a laser cutter to make the stencil is the way to get the best results.
For marking glass, we don't want too much depth, as excessive microcracks can lead to uneven results.
Use a small, stiff paintbrush to remove any debris adhering to the glass surface.
Use a small amount of rubbing alcohol and a paper towel to clean any oil or smudges.
The frosted look can sometimes hide details in the laser engraving. Some paints fill in the sculpted gaps well, then wipe off the excess top layer easily.
Your power, speed and other laser settings will vary depending on the type of project you are working on. Even your laser power and local environment can affect the setup. Therefore, we recommend against arbitrary setups, but material testing. You can download our material tests and logs on our Laser 101 website.
