Cast vs. Extruded Acrylic

Which to choose for your project?

Although at first glance they may seem like the same material, acrylic (PMMA) behaves very differently depending on its manufacturing process. Understanding these differences is key to achieving professional finishes and avoiding material waste.

1. Cast Acrylic

The premium option for artisans and designers.

It is manufactured by pouring liquid acrylic between two glass plates that act as a mold. It is a slower and more artisanal process.

⭐️ Thermal Behavior: Better withstands high temperatures. When laser cutting, it does not melt easily, allowing for polished and clean edges.

⭐️ Machining: It is the "king" of engraving. When laser engraving on cast acrylic, the result is an elegant and crisp matte white. It can be milled, drilled, and polished without the material sticking to the tool.

⭐️ Chemical Resistance: It is more resistant to solvents and cleaning products (less risk of cracks appearing).

⭐️ Weak Point: Since it is manufactured in molds, the thickness can vary slightly within the same sheet (thickness tolerance).

2. Extruded Acrylic

Technical precision and cost savings.

It is manufactured by passing the acrylic mass through rollers that press it until the desired thickness is achieved.

⚡️ Thickness Precision: Its great advantage. If you need a piece to fit perfectly into a 3mm slot, extruded acrylic is your ally because its thickness is almost exact throughout the sheet.

⚡️ Cost: Being a continuous industrial process, it is more economical than cast acrylic.

⚡️ Thermal Behavior: It has a lower melting point. This means it is more sensitive to laser heat; if the power is not adjusted correctly, the edge may be somewhat "gummier" or have melting marks.

⚡️ Weak Point: Not recommended for deep engravings, as the finish is usually transparent or irregular instead of matte white (like cast acrylic).

Comparison Table at a Glance

Technical Details for Experts (What not everyone tells you)

💠 The exception of mirrors: Mirrors are usually made from extruded acrylic. This is because the surface must be perfectly flat so that the reflection is not distorted.

💠 The material's "memory": Cast acrylic has "thermal memory." If you heat and shape it, and then heat it again, it will tend to return to its original flat shape. Extruded acrylic deforms more permanently.

💠 Bonding: Extruded acrylic usually reacts faster to specific adhesives (solvent-based glues), but care must be taken because it is more prone to creating microcracks.

Which should you buy?

✨ Choose Cast if: You are going to manufacture lamps, trophies, pieces with complex engravings, jewelry, or if you are working with thick materials and are looking for the highest visual quality.

✨ Choose Extruded if: You are going to manufacture simple displays, photo frames, pieces where exact thickness is critical for assembly, or if you have a tight budget for large quantities.