Acrylic sheets are widely used in various industries due to their transparency, durability, and versatility. However, there are two main types of acrylic sheets: cast acrylic sheet and extruded acrylic sheet. Understanding their differences helps in choosing the right material for specific applications.
Cast Acrylic Sheet:
● Made by pouring liquid acrylic (PMMA) into a mold (between two glass plates), where it undergoes a controlled polymerization process.
● This results in a homogeneous material with consistent properties in all directions.
Extruded Acrylic Sheet:
● Produced by continuously pushing molten acrylic mass through a die while the chemical process occurs.
● This process creates a heterogeneous material where properties can vary depending on the extrusion direction.
|
Feature |
Cast Acrylic Sheet |
Extruded Acrylic Sheet |
|
Molecular Weight |
High, making itstronger and more durable |
Lower, making itsofter and more flexible |
|
Optical Clarity |
Excellent,free from impurities and distortions |
Good, butmay contain slight imperfections |
|
Surface Hardness |
More scratch-resistant |
Softer, more prone to scratches |
|
Chemical Resistance |
Better resistance to solvents and chemicals |
Less resistant to chemicals |
|
Machinability |
Suitable forCNC cutting, laser cutting, and polishing |
Easier tothermoform and bend due to lower melting point |
|
Laser Cutting |
Produces clean edges with minimal burrs |
Leaves burrs on one side due to internal stress |
|
Laser Engraving |
Engraving appears matte white |
Engraving appears matte gray |
|
Heat Bending & Thermoforming |
No directional behavior, bends uniformly |
Bending behavior depends on extrusion direction |
|
Color Stability in Heat Bending |
Color and finish may change (matt can become glossy and vice versa) |
More stable in heat bending |
|
Thickness Tolerance |
Varies more (e.g., a 3mm sheet may vary by ±0.2mm) |
More consistent (typically ±0.1mm) |
|
Flame Polishing |
Harder to flame polish |
Easier to flame polish |
|
Scratch Resistance |
More resistant to scratches |
Less resistant, scratches more easily |
|
Color Options |
Available in a wide range of colors and thicknesses |
Limited color options |
|
Tension & Stress |
Lower internal stress, more stable |
Higher internal stress, prone to warping in some applications |
|
Minimum Thickness |
1.8mm |
1mm |
|
Cost |
Higher due to complex production process |
Lower due to mass production efficiency |
Because of their different properties, cast acrylic and extruded acrylic serve different purposes.
Cast Acrylic Sheet is Ideal for:
✔ High-end signage and displays
✔ Optical lenses and aquariums (superior clarity)
✔ Laser engraving and precision machining
✔ Medical and laboratory equipment (better chemical resistance)
✔ Decorative and artistic applications
Extruded Acrylic Sheet is Preferred for:
✔ Mass-produced signage and lightboxes
✔ Protective barriers and glazing
✔ POP (Point of Purchase) displays
✔ Furniture and home décor
✔ Thermoforming applications (better bending behavior)
Both cast and extruded acrylic sheets have their advantages and disadvantages.
Additionally, extruded acrylic sheets can be made as thin as 1mm, whereas cast acrylic sheets have a minimum thickness of 1.8mm. This makes extruded acrylic a better option for ultra-thin applications.
When selecting the right acrylic sheet for your project, consider factors such as budget, durability, clarity, chemical resistance, and processing requirements to ensure the best results.
