Laser engraving and cutting have become increasingly popular in the world of DIY and crafting. At the same time, acrylic has become more and more favorable for many enthusiastic due to its numerous benefits. Acrylic is a versatile and durable material that can be used for a wide range of applications, from signage and displays to trophies and home decor. The affordable price and its crystalline aesthetic attract lots of hobbyists and professional users, who seek to express their creativity through this versatile material.

However, processing this material is as not simple as you might imagine. Several considerations should be kept in mind to avoid undesired outcomes.

In this blog post, we will delve into laser engraving and cutting acrylic, covering topics such as the advantages of using acrylic, the distinction between cast and extruded acrylic, and factors that can impact the final result. Additionally, we will explore the different types of lasers suitable for acrylic engraving and cutting and to engrave or cut acrylic using LaserPecker machines.

Topics:  

• What is acrylic and what are the benefits?
• Cast vs Extruded
• Other factors influence the final results
• What types of lasers should you choose?
• How to laser engrave and cut acrylics?

What is acrylic and what are the benefits?

Acrylic, also known as polymethyl methacrylate, is a type of plastic that is lightweight, shatter-resistant, and transparent. It is often used as a substitute for glass, as it is less brittle and more impact-resistant. Acrylic can be produced in a variety of forms, including sheets, rods, tubes, fibers, resins, and paints.

As a thermoplastic, acrylic can be melted and reshaped through the application of heat. This property, combined with its exceptional optical clarity, weather resistance, affordability, and easy processing, has made acrylic a popular choice for a wide range of applications, especially for laser engraving and cutting.

(Color and Half-transparent acrylics Source: Wikipedia)

The laser engraving is a process of emitting laser beam from laser machine onto the acrylic and melt or vaporize the micro-surface to leave visible and permanent marks. Laser cutting, on the other hand, is to make the laser beam penetrating through the acrylic completely to form a leave and form a certain type of shapes. Before any operation, it is essential to establish appropriate settings for each approach accordingly

Some benefits of using acrylic for laser engraving and cutting include:

• Versatility: Acrylic can be used for a wide range of applications, including signage, displays, lenses, awards, trophies, jewelry, home decor, and art and crafts etc.

• Durability: Acrylic is resistant to shattering and cracking, making it a long-lasting material for laser engraving and cutting projects.

• Transparency: Acrylic is transparent, allowing for intricate designs and patterns to be laser-engraved or cut into the material.

• Ease of use: Acrylic is easy to work with, making it a great choice for beginners and experienced laser engravers as well.

Cast acrylic VS Extruded acrylic

Acrylics differ from each other according to their additives and different manufacturing processes. For laser engraving and cutting, the main materials used are acrylic sheets which come in 2 forms: Cast acrylic and Extruded acrylic. They have different properties that make them suitable for various applications.

Cast acrylic sheets are made by pouring liquid acrylic resin into molds, where it is allowed to cool and solidify. This production process results in sheets with an optical-grade, glassy-smooth surface that is shiny and transparent. The molecular structure of cast acrylic also makes it more rigid and impact-resistant, but it is also more expensive. And since it is produced by pouring different volumes of liquid acrylic, sometimes it is hard to obtain a consistent thickness of different sheets.

On the other hand, extruded acrylic sheets are made by pushing heated acrylic resin through an extruder, which presses the material into continuous sheets. This process results in acrylic sheets that have a matte surface with tiny hairline scratches. Extruded acrylic has a relatively more pliable molecular structure, so it is less rigid and impact-resistant than cast acrylic. However, extruded acrylic is more affordable and can better withstand high-volume production.

It is hard to distinguish two types of acrylics only by sight before engraving, since they have the similar appearance. Some suppliers may list types of acrylics on their product description, if you want to purchase acrylics, please make sure you make the right choice.

Only the final laser engraving results can truly distinguish them. Cast acrylic, in particular, can have a final result of a clean and frosty white color, which is achieved through its highly uniform molecular structure. The uniform molecular structure of cast acrylic means laser energy is absorbed evenly across the material, resulting in clean, consistent engraving. The smooth, glossy surface of cast acrylic also allows for superior laser engraving quality with fine detail and resolution.

In contrast, extruded acrylic has an uneven, porous molecular structure that absorbs laser energy unevenly. This can lead to shallower engraving results. The scratched surface of extruded acrylic also does not allow for the same engraving quality and fine detail as cast acrylic.

Therefore, cast acrylic is the preferred material for laser engraving. The color engraved is more vivid and prominent than that of extruded acrylic.

(From left to right, there are engraved extruded acrylic with protective paper, engraved extruded acylic without protective paper, and cast acrylic without protective paper. Source: yellowzepplin)

When it comes to laser cutting, the choice of acrylic material is less crucial than engraving. Since laser cutting is the process of allowing laser beam to penetrate through the acrylic plate entirely, meaning the choice of acrylic types has minimal impacts onto the final results.

That being said, extruded acrylic can still produce satisfactory results at a lower cost than cast acrylic in laser cutting.

The choice between the two to do the engraving or cutting work ultimately depends on the specific requirements of the project and the available budget. While cast acrylic may be preferred for high-end applications that require superior clarity and consistency, extruded acrylic may be a more practical choice for projects where cost is a significant factor.

Moreover, acrylic enthusiasts may wish to reshape the material into different forms using thermal tools. However, it is worth noting that cast acrylic requires more time and effort to reshape due to its higher thermal resistance, which also makes it less likely to crack during the process.

Other factors when choosing acrylics

While the type of acrylic (cast vs extruded) is important for laser processing quality, there are several other factors to consider.

Color: Color is another crucial factor to consider when selecting acrylic for laser engraving and cutting. Acrylic can be broadly categorized into three main types based on color: transparent, opaque, and half-transparent acrylics with other colors.

It is worth noting that cast acrylics offer a wider range of color options than extruded acrylics, making them a preferred choice for projects that require specific shades or decorations.

Opaque acrylics with various colors are generally well-suited for laser engraving and cutting applications. However, transparent or half-transparent acrylics may require additional procedures depending on the type of laser used for processing. We will delve into the specifics of these procedures in the latter section.

Thickness: Another important factor is the thickness of the acrylic. Thicker acrylic will require more power and time to engrave or cut, and it may also produce more smoke and fumes. It is important to use the correct settings for the thickness of the acrylic being worked with. We will explore the settings using LaserPecker machines for reference in the latter part.

What types of lasers should you choose?

Based on the categories of gain medium, there are 3 main types of lasers available in the market for laser engravers: CO2 laser, Diode laser, and Fiber laser.

The fiber laser is not very suitable for laser cutting acrylic since it has a wavelength of (1.064um)1064nm which is too short to be absorbed by acrylic, makes the laser beam hard to penetrate through the acrylic plate. And it would leave shallow marks on the surface of acrylic which does not offer an expected outcome.

CO2 laser, on the other hand, is the ideal laser for processing acrylics. It has a wavelength of 10.6 um (10600nm) which is 10 times that of fiber laser and can be well absorbed even by transparent acrylics, since its wavelength is long enough and falls into the infrared region.

A CO2 laser is a type of gas laser that uses a mixture of carbon dioxide, nitrogen, helium and other gases as the gain medium. The CO2 laser works by ionizing a glass tube filled with this gas mixture. These molecules then release photons of a specific wavelength that bounce back and forth in the tube with the aid of opposing mirrors, one of which is semi-transparent. The semi-transparent mirror allows some photons to escape and form a laser beam that can be focused and directed to the acrylic material.

(The mechanism of CO2 laser engraver. Source: Snap Maker)

A CO2 laser can engrave and cut both cast and extruded acrylic with high quality and accuracy. A CO2 laser can produce a smooth, flame-polished edge when cutting extruded acrylic, and a frosty white contrast when engraving cast acrylic. The high power and quality beam provided by CO2 laser can also cut and engrave various colors, textures, and thicknesses of acrylic.

The Diode laser, or other visible lasers with the wavelength of 0.4-0.5 um (400nm-500nm) has limited functions to engrave or cut acrylic, especially when the acrylic is transparent. Because transparency means acrylic cannot absorb visible lights.

So, no matter for engraving or cutting, a half-transparent colored or an opaque acrylic is recommended for those visible light lasers.

How to engrave acrylics?

For reference of laser engraving, we can use LaserPecker LP2 as an example.

LaserPecker 2: Small & Smart Laser Engraving | Wood Engraving – laserpecker.net

As an example of laser engraving, the LaserPecker LP2 is a second-generation device in the LaserPecker series that features a 5-watt, 450nm NICHIA diode (or blue light) laser with an ultra-fine 2K resolution. While the LP2 is well-suited for engraving on non-transparent acrylics, it can also be used to engrave on transparent acrylics by following some simple procedures, as demonstrated in the example below.

The images above showcase a transparent acrylic table showpiece with an electric base that offers LED lighting. Acrylic sheets typically come with a protective adhesive film on both sides to prevent scratching. We recommend removing this protective film before engraving to ensure optimal results. To make the acrylic opaque, there is no need to switch to another laser head. Instead, you can simply paint the surface with a black marker, which will effectively block the transmission of light through the acrylic.

Afterwards, you can use software like Adobe Illustrator to create your own design, or find pre-made designs online. The LaserPecker APP also provides default patterns or a design space for your creation, it also supports you to upload your own high-resolution pictures with various formats.

Software – laserpecker.net

Place your acrylic plate into the working area and set the focal length by putting down the L-shaped ruler to touch the surface of acrylic plate (or just measure the 11cm distance between machine and plate surface).

Using Bluetooth to connect the LaserPecker LP2 machine and upload your design profile and you can preview the engraving area. You can choose the built-in setting recommendations or set your own customized setting, such as the power, depth and the pass. The recommended settings used in this example include a 2k resolution, 100% power, 15% depth, and 1 pass. Now you can start engraving!

Once the engraving is complete, clean off the black marker paint using a mixture of alcohol and water. Attach the engraved acrylic to the electrical base, and your personalized table showpiece is ready!

For laser cutting, we recommend LX1 from LaserPecker, as it is the frame-structural machine that provides interchangeable laser heads with 10W and 20W power blue lasers. The power is suitable for cutting 8mm and 10mm black acrylic accordingly.

Preorder-LaserPecker LX1 – laserpecker.net

The procedure is similar to that of LP2. First, place your acrylic plate on the working area. Next, connect your APP to the LX1 via Bluetooth and upload your design file, and you can also design your own pictures on the Creation Page. The LX1 will automatically display a preview of the cutting area after you press the preview button on the APP.

Afterwards, you can adjust the cutting distance with the help of a small vernier. Lower the vernier until the scale on the laser head is equal to the thickness of your acrylic plate. Once the distance is set, raise the vernier and your plate is now ready for cutting!

To begin the cutting process, set the desired parameters on the LaserPecker APP or software and press the start button. Remember to wear protective goggles as the blue laser generated by the LX1 is visible and may harm your eyes.

The recommended settings used in previous example is 100% power, 99% depth(the depth determines whether it is engraving or cutting), and 1 pass, with a 20W blue light laser and a 3-4mm black acrylic pate.

Moreover, it is important to note that when laser cutting acrylic, it is better to use thicker sheets (more than 4mm) and cut larger shapes, as thinner strips can be easy to break. The thicker the acrylic, the more rigid it will be, which can help prevent cracking during the cutting process.

Additionally, it is strongly recommendable to cut acrylic in a well ventilate environment. As when laser cutting acrylic, the process might produce a smell that can be very unpleasant and harmful to the user if inhaled. The LX1 provides an air duct design that can blow away the dust generated during work and improve the cutting/engraving effect and protect your machine.

Conclusion

In conclusion, laser engraving and cutting is a highly versatile and precise method for processing a wide range of materials, including acrylic.

When selecting acrylic for laser processing, it is important to consider factors such as color, type, and thickness, as well as the type of laser being used. CO2 lasers are the preferred choice for processing acrylics due to their longer wavelength and high-power output, which allows for high-quality and precise engraving and cutting.

Diode lasers and other visible light lasers can also be used for engraving and cutting acrylics, but they have limited functions in their capabilities and are best suited for opaque or colored acrylics.