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Laser Etching and Engraving Glass: Expert Guide

Laser Etching and Engraving Glass: Expert Guide

Laser Etching and Engraving Glass: Expert Guide

Laser etching and engraving are great ways to personalize and create designs on all kinds of glass.

With the advancements in laser engraving technology, such as the rotary axis, it's even possible to work on curved glass surfaces such as bottles and drinking glasses.

The non-contact nature of laser engraving offers several advantages over traditional glass engraving techniques like sandblasting and CNC engraving.

However, the reflective nature of glass can present various challenges that you need to be vary of.

This article discusses the process of laser engraving and etching glass, its applications, and the types of glass used while comparing it with other techniques used for engraving glass.

In the end, I'll also recommend some laser cutting machines and services that offer etching or engraving of glass.

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Laser Etching and Engraving Glass- The Basics

Laser etching and engraving glass produces a permanent mark with a frosted look. Laser etching glass alters the surface at a maximum depth of 0.001” and requires comparatively lower laser power than engraving. Generally, a CO2 laser with a laser-power of above 30W is ideal for engraving/etching glass.

Glasses can be etched, engraved, scored, or cut using a laser. This article strictly talks about the laser etching and engraving aspects of glass.

Laser etching and engraving are two of the most popular methods used in personalizing glassware.

Etching Glass

Mirror engraving done on COMGO Z1
Laser etching the glass of a mirror

When glass is etched, the laser alters the topmost surface layer of glass. Typically, the maximum depth-of-cut in etching is around 0.001".

Masking and polishing the glass, and reducing the grayscale of the image by 20% will improve the quality of etching and produce a high-contrast mark.

Furthermore, using low-resolution images will result in better etching on glass because higher resolutions can produce deep, crowded fractures, thereby affecting the clarity of the mark.

Engraving glass

Engraving and cutting glass using xTool D1 Pro
Engraving in glass by using a laser to create micro fractures

Laser engraving vaporizes the material and produces a cavity on the surface of the glass.

Generally, laser engravings on glass have a maximum depth of around 0.02" to 0.125".

Sub-Surface Laser Engraving (SSLE) is a popular technique used to engrave 2D and 3D images inside a block of glass.

In this technique, an additional parameter called Z-factor or height is considered to focus the laser beam inside a glass.

Glass having high optical clarity are used for producing SSLE. This helps the laser beams to effectively pass through the glass and focus on the right spots.

Although laser etching or engraving glass can throw up some challenges, there are various techniques you can learn to improve the quality of your engraving.

The following video provides a detailed guide to engrave glass using a diode laser.

YouTube video

The Process - Laser Etching and Engraving Glass

Creating the Design

Preparing the design in CAD
Preparing the design in CAD

To get good engraving or etching results on glass, you have to optimize the images to reduce the risk of crowded fractures.

For designing, you can use CAD software that exports files in raster or vector image formats like BMP, GIF, JPG, PNG, TIFF, EPS, SVG, AI, etc.

Generally, raster images are used for engraving applications. However, vector images are ideal for applications that require scaling of the images in the control software.

Image Settings Laser Engraving Glass

ParameterSetting
Image ModeUse Threshold instead of Grayscale
Resolution500 DPI
Rasterization TypeOrdered Dithering

Recommended image settings for laser engraving glass

For laser engraving glass, images transformed to threshold mode and a resolution of 500 DPI or higher produce the best results.

Grayscale vs Threshold
Grayscale vs Threshold

Although a 70% grayscale setting produces satisfactory results, a threshold image produces far superior results due to a single color tone.

Engraving glass with a grayscale image can result in a crowded fracture that will produce an engraving with a comparatively poor visibility

When rastering an image for laser engraving, you can use an ordered dithering algorithm.

Each dot in the image is made small or large in ordered dithering depending on its grayscale value.

The designs used in sub-surface laser engraving are converted to point cloud files that represent the image data in a three-dimensional space using focus points.

Image Settings Laser Etching Glass

ParameterSetting
Grayscale80% Black
Resolution300 DPI
Rasterization TypeJarvis Dithering

Recommended image settings for laser etching glass

For laser etching glass, images optimized to threshold mode or 80% grayscale and resolution set to 300 DPI or lower work best.

With a lower DPI, the microfractures produced on the glass surface will be at a safe distance from each other and will be less prone to shattering.

When rastering images for an etching application, you can use Jarvis dithering algorithm. It reduces the number of dots in the image and increases the job speed.

Laser ON - Running the Job

Laser engraved falcon on glass
Laser engraved falcon on glass

Before executing the cut, you need to set the optimal parameters for laser etching and engraving glass.

The optimal parameters for laser engraving and etching glass are given in the tables below.

ParameterSetting
Output Power30W and above
Laser TypeCO2 laser
Lenses1.5" or 2"
Engraving Speed~822 ipm with a 60W laser
MaskingDampened paper towel
Air AssistNot required

Optimal settings for laser engraving glass
ParameterSetting
Output Power20W and above
Laser TypeCO2 or Diode
Lenses1.5" or 2"
Etching Speed~708 ipm with a 100W laser
MaskingBlack spray paint
Air AssistNot required

Optimal settings for laser etching glass

Performing Test Runs

Test runs performed on glass using 20W diode laser
Test runs performed on glass using 20W diode laser

The optimal parameter for laser etching and engraving vary from one setup to another and from one type of glass to another.

Therefore, it is recommended to perform test runs on the glass that you plan to use for your job.

You can switch between different power, speed, and image parameters to find the settings that produce the optimal results.

Testing the materials beforehand helps you understand them better, and once you have the proper settings, you can run the job.

Preparing the Workpiece

Preparing the glass workpiece for diode laser engraving
Preparing the glass workpiece for diode laser engraving

Before placing the glass piece on the workbed, make sure it's well-cleaned and is free of dust or oil pigments.

You can use glass cleaners like Windex and follow it with a denatured alcohol cleaning.

When the laser incident face of the glass is covered with a dampened paper towel, it produces white frosted engravings on glass surfaces.

For grayish engravings, you can apply masking tape over the glass surface.

When applying masking tape, it must be ensured that no air bubbles are trapped between the masking tape and the glass surface.

The masking of glass is mandatory when using a diode laser because diode lasers are ineffective on transparent surfaces.

Applying a uniform coat of black paint makes the workpiece opaque and helps in engraving the glass.

It must be noted that, when using black paint to mask the surface, the engraving should be performed with the non-coated face towards the laser.

This requires you to mirror the design pattern before executing the process.

Laser marking of dense intricate patterns in an area can result in overheating of the material and fracture the workpiece.

A handy trick to avoid unwanted fractures of glass during intricate patterns is to cover the surface with liquid soap.

Furthermore, if your application involves engraving/ etching on curved surfaces, you have to install a rotary axis on your laser engraver.

Laser Type and Power

For engraving glass, CO2 lasers operating at a wavelength of 9,300nm or 10,600nm are the best option.

When using a 60W CO2 laser to engrave glass, it is recommended to use 12% power with an engraving speed of around 822 ipm.

The ability to engrave glass with low-powered lasers makes it possible to use UV lasers, operating at a wavelength of 355nm, to etch and engrave glass.

Diode lasers, such as 20W xTool D1 pro can be used to engrave glass at 45% power and an engraving speed of around 1200mm/min.

Engraving/Etching Speed

PowerModeSpeedDPIHatch spacing
40W (12%)Engraving~826 ipm4620.055 mm
60W (12%)Engraving~846 ipm4620.055 mm
65W (27%)Engraving~768 ipm3000.065 mm
80W (12%)Engraving~866 ipm4620.055 mm
100W (25%)Engraving~768 ipm3000.065 mm
100W (40%)Etching~708 ipm3000.07 mm
150W (20%)Engraving~768 ipm3000.065 mm

Etching and Engraving settings for CO2 lasers

Hatch Pattern

Hatch patterns and Line spacing for engraving glass
Hatch patterns and Line spacing for engraving glass

Unidirectional and Bi-directional patterns are the most common hatch patterns mimicked by laser engravers.

By default, most laser machines use a bi-directional hatch pattern for engraving operations, which produces good results for engraving and etching glass.

However, a unidirectional hatch pattern is preferable for engraving thin glass that is prone to overheating.

The unidirectional pattern is comparatively slower than the bi-directional hatch and provides intermittent cooling time to prevent overheating of the workpiece.

Generally, a line spacing greater than 0.01mm produces the best results for the etching or engraving of glass. Anything lesser than that will result in a crowded fracture of glass.

You can adjust the hatch settings on most laser engraver or cutter software. A hatch pattern with a small line distance gives engravings with greater details and vice versa.

Lens

You can use a 1.5" or 2" lens for etching and engraving glass. Anything above 2" will result in unwanted fractures, making it prone to shattering.

A 1.5" lens produces the best results with micro-fractures that results in a detailed engraving.

Focus

Glass is a sensitive material, and it needs to be kept at the right focus plane of a laser beam.

If you deviate from the focus, you'll get flacking, chipping, and irregular fracturing on the glass surface.

Air Assist

Air assist support is not required for etching or engraving glass. But if you have an adjustable pump, you can adjust it to low-pressure mode. This helps remove any surface debris and also cools the glass surface.

In most cases, you don't need to use an air assist for working on glass, especially when using a rotary, as the airflow can interfere with the job.

Black Engraving On Glass

You can engrave black marks on glass surfaces by placing the glass on top of a stainless steel plate and using a fiber laser to mark it.

The fiber laser beam passes through the transparent glass and engraves the stainless steel plate.

The backlash from the steel plate results in black marking on the glass surface.

With a galvo head, a 30W fiber laser operating at a frequency of 20KHz can black engrave glass at a speed of around 2,362 ipm.

Post-Processing

Cleaning off the paint after engraving
Cleaning off the paint after engraving

Laser etched or engraved glass needs further processing to remove the masking layer, paint, and shards from its surface.

The masking layer can be gently removed by hand, but you need to wash it or slowly rub it using a moist cloth to remove the paint.

Shards are a little tricky to remove. They can be sharp, so use cut-resistant gloves while handling such glass pieces.

To effectively remove the shards and retain a polished surface, you can use a wire brush to clean the etched or engraved surface.

You can also enhance the contrast of the engraving by filling the engraved surface with paint and wiping off the residual paint with a microfiber cloth.

You can also use an led light to highlight the engraving pattern, making it ideal for projects such as desk lamps.

LED lit laser engraved glass
LED lit laser engraved glass

Glasses Commonly Used for Laser Etching and Engraving

Soda-Lime Glass

Soda-lime glasses are one of the most widely used glasses and cover around 90% of all glass applications. It has carbonate and calcium oxide as its building blocks.

A CO2 laser can easily etch and engrave soda-lime glass.

Silicate Glass

Aluminosilicate and Borosilicate are the most popular types of silicate glass used for laser engraving and etching projects.

Borosilicate glass, especially its BK7 and K9 versions, is used in the sub-surface laser engraving technique.

Aluminosilicate glass is less prone to scratches and is widely used to build Gorilla glasses for different gadgets.

Stained glasses

Stained glasses have added color additives. They can be laser etched or engraved easily, but if the color additives have lead content you won't get a uniform result.

Pressed or Molded Glass

Pressed or molded glass is generally used to make different glassware products, and most of these glassware products can be etched or engraved using a laser.

Sheet Glass

Sheet/Plane/Flat glasses are commonly laser processed to etch or engrave designs, text, or images onto their surface. They are used in windows, doors, walls, etc.

Mirror Glass

Mirror glass can be engraved with a fiber or CO2 laser. The fiber laser gives a clear/transparent engraving, while the CO2 laser gives a frosted effect.

The laser beam from fiber lasers passes through the glass and engraves on the backside of a mirror.

Glasses that can't be Laser Etched or Engraved

Glasses containing metal additives such as lead, zinc, gold, etc., can't be etched or engraved on a CO2 laser as they are not good at working with metals.

Even fiber lasers that are good at processing metals can't work on metal-doped glasses. This is because laser beams from fiber lasers easily pass through glass.

As the fiber laser beams pass through metal-doped glasses, the metal heats and expands, causing uneven fractures and eventually breaking the glass.

Etching and Engraving Glass using Laser vs. Other Alternative Methods

Traditional engraving of glass
Traditional engraving of glass (Source: Bored Panda, Lesley Pyke Glass Engraver - YouTube)

Generally, glasses are engraved using mechanical engraving techniques that use sharp tools to scratch and remove layers of glass.

These tools were handheld like a pen while carving on glass. Sometimes the tools were also motorized for faster material removal.

Sandblasting is also a popular technique used for engraving glass, but it has a long work cycle compared to laser.

Accuracy and Repeatability

Compared to traditional techniques of engraving glass, laser engravers have higher accuracy and can work on repeated jobs with a high repeatability rate.

There is a higher chance for errors in traditional cutting techniques, and it's almost impossible to get similar results on repeated jobs.

Non-contact

Unlike traditional engraving techniques, there is no contact between the tool and the workpiece in laser engravers, so you don't need to clamp the workpiece.

This eliminates different forces acting on the glass while working with it and prevents unnecessary fractures.

Also, a laser-etched or engraved glass only requires minimal post-processing.

Shape of Glass

In laser machines, you have the limitation of working on flat-surfaced and cylindrical/conical (using rotary attachment) glass workpieces. It is because lasers have a focus plane that they can efficiently work on.

In the case of traditional engraving techniques, you do not have this limitation as you can use sharp tools to work on the nooks and corners of different workpieces. It's beneficial when working on irregularly shaped glassware.

Versatility

With a laser engraver, you can not only engrave but can also etch on glass.

Laser etching of glass is a chemical process in which air bubbles and moisture are trapped in the fractures developed when exposed to a laser beam.

Such etching techniques are not possible with traditional tactics used in processing glass.

Work Cycle and Time

In the case of work cycle and time, laser cutting beats most other techniques as it can process glass much faster.

It's because they are computer-controlled and can work independently without human intervention.

High Initial Cost

Laser engravers cost much more than buying a motorized tool for manually engraving on glass.

Even though laser engravers come with a higher price, they can easily pay for themselves when used smartly.

You can create many different projects on a laser machine and sell them to cover their price.

Know-How

To operate and work with laser machines, you need to know their working mechanism and work with different laser cutter/engraver software.

It'll take some time to cope with laser machines and their related software programs for someone new to laser machining.

You do not have such limitations in other manual glass engraving techniques, but it too requires some skill.

Applications of Laser Etched or Engraved Glass

Applications of laser engraving glass
Applications of laser engraving glass

Laser engraving and etching of glass are used to customize glassware, trophies, mementos, decorate glass panels, mirrors, etc.

Laser processed glasses are also used in automotive industries, optics, medical equipment, etc.

Best Laser Machines for Etching and Engraving Glass

OMTech 60W CO2 Laser Machine

OMTech 60W CO2 laser machine
OMTech 60W CO2 laser machine

OMTech 60W CO2 laser machine has a cabinet-type design and weighs around 331 lbs.

It has a footprint of 47.24" x 34.25" and a work area of 20" x 28".

Even though it has an enclosed setup, it has two pass-through doors. This helps you process larger workpieces that can't be otherwise housed inside the work area.

The laser module operates at a wavelength of 10,640 nm and has a maximum lifetime of 2,000 hours.

OMTech 60W CO2 laser machine has two variants, AF2028-60 and MF2028-60. Its AF2028-60 variant has an autofocus feature, but the MF2028-60 variant doesn't.

In addition to glass, it can also work on cardboard, paper, plastics, rubber, ceramics, marble, granite, leather, textiles, wood, cork, acrylic, plastic, and more.

OMTech 60W CO2 laser machine can engrave at a maximum depth of 0.39", a resolution of 4,500 DPI, and a speed of 1,416 ipm. Its maximum cutting speed is 942 ipm.

Along its X and Y-axis, it's driven by separate belt drives motorized by NEMA 57 stepping motors.

OMTech provides a license for LighBurn software with the machine. It can run on Windows, Mac, and Linux OS.

It also works with RDWorks, CorelLaser, and LaserDRW software programs.

OMTech provides a two-year warranty for the laser machine and six months for the laser tubes.

They have good community backing, and most of the discussions related to OMTech's machines are happening on their user-only Facebook group.

A detailed review of this product can be found here– OMTech 60W CO2 Laser Review

OMTech 60W CO2 Laser
60W CO2 laser without Autofocus.
Comes with RDWorks and LightBurn Software.
2-year warranty.
OMTech 60W CO2 Laser with Autofocus
60W CO2 laser with Autofocus feature.
Comes with RDWorks and LightBurn Software.
2-year warranty.

Trotec Speedy Series

Trotec speedy series of laser machines
Trotec speedy series of laser machines (Source: Industry Arena)

Trotec Speedy Series of laser machines are a good pick for anyone wanting to do laser etching or engraving on glass.

They are available in fiber and CO2 laser variants. For working on glass, a CO2 laser is the best option.

It is available in CO2 laser output powers ranging from 30W to 120W. You can also choose from four different sizes of machine.

Speedy 100Speedy 300Speedy 360Speedy 400
Footprint40" x 30.8"
(1018 x 784 mm)
44.5" x 37.1"
(1130 x 943 mm)
48" x 32.6"
(1221 x 830 mm)
56.2" x 37.5"
(1428 x 952 mm)
Work Area27.2" x 13.6"
(690 x 346 mm)
31.3" x 17.3"
(795 x 440 mm)
35" x 23.6"
(890 x 600 mm)
43.1" x 27.4"
(1096 x 698 mm)
CO2 laser power30 - 60W30 - 120W60 - 120W60 - 120W

A quick comparison of speedy series of laser machines from Trotec

Its laser beam has a beam quality of ≤1.2 M2 and has a spot size of 120 µm. This helps focus a high-intensity beam on the material surface.

The speedy laser machines work with Trotec's JobControl and Ruby software. These are control software but also support basic CAD operations.

Trotec's machines are best suited for businesses and regular hobbyists. With the machine, they also provide you a lifetime technical support.

They have an active community, and they also run special training sessions for their customers through webinars.

Trotec provides a two-year warranty for the speedy series of laser machines, but for some components like the optics, motors, drives, etc., they provide a limited warranty.

For queries, you can contact Trotec through phone and email.

Laser Engraving Services for Glass

Using different local or online laser engraving services that offer etching and engraving of glass is a good option if you don't have the necessary skill or are not interested in buying a laser machine.

Following are some online laser engraving services that offer etching and engraving of glass. Some of them also have their local branches in USA.

Final Thoughts

Both laser etching and engraving are great ways to mark on glass.

When working with delicate glass, you can use laser etching to alter a thin surface layer of glass. Laser engraving can be used when you want the mark to have a visible depth.

Etching and engraving glass with a laser has many advantages over traditional techniques, and such glasses are used in many different applications.

Furthermore, the non-contact nature and ability to produce intricate patterns without shattering the glass makes laser etching and engraving ideal for producing permanent marks on fragile glass workpieces.

Laser Cutting and Engraving Other Materials

Following are some detailed guides on laser cutting and engraving different materials.

MaterialLink to Guide
VinylLaser Cutting Vinyl
PlywoodLaser Cutting Plywood
AluminumLaser Cutting and Engraving Aluminum
LeatherLaser Cutting and Engraving Leather
FabricLaser Cutting Fabric
FoamLaser Cutting Foam
PlasticLaser Cutting and Engraving Plastic
PolypropyleneLaser cutting polypropylene
BrassLaser Engraving Brass
FeltLaser Cutting Felt
GraniteLaser Engraving Granite
MetalLaser Cutting Metal
Glass (cutting)Laser Cutting Glass
Glass (engraving)Laser Etching and Engraving Glass
Wood (cutting)Laser Cutting Wood
Wood (engraving)Wood Laser Engraving

Laser engraving and cutting guides for other materials

Frequently Asked Questions

Where should I place the wet paper towel while etching glass, inside or outside the glass?

You should place the wet paper towel on the surface of the glass while etching it. The goal of placing wet paper towels outside the glass surface is to minimize the surface heat and keep the fracturing effect from affecting the glass much. Placing the wet paper towel inside the glass won't help dissipate the heat or control the effect of fracturing.

Can I leaser engrave on porcelain?

Yes, you can laser engrave porcelain. It can be laser engraved with the same settings used for glass, but it tends to give engraves with less contrast. Porcelain is very similar to glass and its composites.

What are the types of glasses that can be laser etched or engraved?

With a laser, you can etch or engrave on glasses like soda-lime, aluminosilicate, borosilicate, stained, pressed/molded, sheet, mirror, etc.

About John

Hey I'm John. I talk about CNCs and Lasers at Mellowpine. If you have any questions related to CNCs or Lasers, I'd be happy to answer them. Reach me at mail@mellowpine.com

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John

Hey I'm John. I talk about CNCs and Lasers at Mellowpine. If you have any questions related to CNCs or Lasers, I'd be happy to answer them. Reach me at mail@mellowpine.com

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