What is the difference between extruded acrylic sheet and cast acrylic sheet?
Acrylic is a very versatile material used in a variety of environments. There are many variations of acrylic sheets, including: Transparent, color, mirror, matte and even matte aluminum effect.
Represented and molded acrylics are the two main types of skin polys you come across. At first they look the same, but the two have very different characteristics, one is much more expensive than the other.
It is important to know the difference between the two so that you can choose the type that best suits your needs. Cast and extruded acrylic sheets depend primarily on the thermal and chemical properties caused by the manufacturing process. As outlined below, there are also some other differences that you may want to consider when choosing an acrylic sheet for your home DIY project.
Important differences to remember when working with acrylic sheets:
Difference in thickness
Depending on the method of manufacture colored plexiglass of the sheet, molded acrylics tend to have a slight change in sheet thickness, while extruded sheets are much more uniform and show little change. This makes extruded acrylics ideal for vacuum forming and situations where more detailed and precise shapes are required.
Cast acrylics have an isotropic response to temperature. That is, there is a maximum of 2% shrinkage in all directions. It may be important to note that acrylic expands and contracts much faster than glass. On the other hand, the expressed acrylic shows a difference in shrinkage depending on the thickness and extrusion direction.
Advantages of extruded sheet
Decreased mechanical properties mean a process advantage over cast acrylics during bending, heating and vacuum formation
Better thickness tolerance
The low viscosity at high temperatures means that it is more flexible than molded acrylics.
Advantages of molded acrylic sheets
Better thermal stability
Improved crack resistance when exposed to solvents (when forming a network of very small cracks)
Wider thermoforming range than extruded acrylic
Better ability to be hot processed
Excellent surface finish and optical properties.
Both types of acrylic have the advantage of being durable and long lasting, and are highly resistant to natural aging. Most manufacturers offer a 10-year warranty against noticeable yellowing.
It is often unclear what type of acrylic you are buying, especially online.