When you're in the market to buy plastic sheets, it's likely you're going to come across acrylic. Acrylic sheets are a big point of focus for those who like to experiment with laser cutting or want take advantage of their versatility for thermoforming. Acrylic sheets come in either cast acrylic and extruded acrylic variations. In this article, we will explore what kind of acrylic sheets work the best for laser cutting, and what the differences between these two sheet types are.
How to Tell the Difference Between Extruded and Cast Acrylic?
Cast and extruded acrylic look the same when side by side. While both extruded and cast acrylic can come with plastic film masking, typically, if your plastic is paper-masked it is a good indication that it is cast acrylic.
A lot of colored acrylics tend to be cast acrylic because it's easier to add color to cast compared to extruded. Conversely, mirrored acrylics are pretty much extruded-exclusive. Every acrylic on Forged Acrylics is labeled as either "cast" or "extruded" but most of the acrylic we carry is cast.
What is Extruded Acrylic?
Extruded acrylic sheets are an affordable option that many people use for its convenience, extruded-exclusive colors, and the opportunity to save money. It is uniquely made with a process involving rollers. The liquid is moved through the rollers to add texture after a heating process. Over time, the sheet is formed.
This kind of acrylic sheets are favored because of their low price. Anyone working on a budget will likely benefit from these depending on what they are making. Extruded acrylics also have a high level of clarity and are considered to be fairly durable. Extruded acrylic sheets can be used for laser cutting, but they are not very good at being laser engraved because the results are grainy and lack contrast.
What is Cast Acrylic?
Cast acrylic is the holy grail for laser cutting, laser engraving CNC machining and thermoforming applications. It's the most popular kind of sheet specifically because of its higher-than-average quality. It is made using methyl methacrylate monomer liquid in a mold. After the liquid fills the mold, warm water is used to start the polymerization process.
It's more durable and can provide an impressive clarity that suites laser cutting, laser engraving, or CNCing. It is also known for its impressive thermal stability that makes it easy to work with. Unlike extruded acrylic sheets, cast acrylic sheets come with a higher degree of variation in overall thickness due to the mold making process.
Typically, cast acrylic is paper masked rather than film masked and every cast acrylic sheet sold by Forged Acrylics will be paper masked.
Why is Cast Acrylic Better than Extruded?
In general, cast acrylic is going to be your go-to plastic for most applications. It is created using high-quality materials and is known for its above-average performance. People value its exceptional clarity and durability. Though it does come at a higher price point, it is often considered to be well worth the extra money for most projects.
Cast acrylic is an ideal laser cutting material because it laser engraves significantly better than extruded does. Where extruded acrylic engraves with a grainy blotchy texture, cast acrylic has a cleaner frost look with a higher contrast praised for its consistency. When laser cut, the heat creates nice flame-polished edges..
Extruded acrylic is less than ideal for laser engraving, but is acceptable for laser cutting purposes if you don't intend on engraving it.
Conclusion
| Usage | Extruded Acrylic | Cast Acrylic |
| Laser Cutting | ✔️ | ✔️ |
| Laser Engraving | ❌ | ✔️ |
| CNC Machine | ❌ | ✔️ |
| Heat Bending | ✔️ 🥈 | ✔️ 🥇 |
| Mirrored Acrylic | ✔️ | ❌ |
Any time that you are looking to improve your laser cutting process, you can always benefit from better materials. While extruded acrylic is favored by some for its low price tag, cast acrylic is well worth the investment and offers great and consistent results. If you are looking for the chance to explore cast acrylic, but are not sure where to start, try the Forged Acrylics Cast Acrylic Variety Sampler Pack.
Want to see the plastics in action? See the side by side acrylic showdown from Youtuber Maker Experiment:
