Acrylic (PMMA)

We have a large inventory of plastic materials, allowing us to accommodate requests for items made from standard materials within 8-14 business days, depending on the complexity of your components.

If your project requires more specialized plastic, such as acrylic in custom colors, we typically operate within a month.

We only work with European suppliers, ensuring that we can quickly order materials tailored to your needs.

At Induflex, we can achieve very tight tolerances in plastic.

When you order a plastic part from us, it will comply with Danish Standard ISO 2768-1 (medium) by default. We measure the tolerances at room temperature, around 21 °C.

Of course, we can agree on different tolerances if you wish.

Like many other thermoplastics, acrylic is stress-sensitive. Therefore, designs should be made without sharp internal corners.

If a design combines stress concentration with internal stresses, it doesn’t take much for the acrylic to crack during processing, transport, or initial use.

Internal stresses are well-known in extruded acrylic due to the fabrication method of the raw material, but stresses can also be created by improper flame polishing, laser cutting, or using incorrect tools.

Internal stresses in acrylic can be relieved through annealing, which involves slow heating and cooling.

In clear acrylic, stresses can be visually detected using two pieces of polarizing filter. Place the acrylic behind a light source, lay the filters on top of each other, and observe the acrylic through the filters while rotating them relative to each other. The stresses will now become visible.

Acrylic is produced in two versions: cast acrylic (known as acrylic ST) and extruded acrylic (known as acrylic XT).

Cast acrylic is made by mixing the components of acrylic in molds. A chemical process occurs in the mold, creating a homogeneous material with the same properties in all directions.

Extruded acrylic, on the other hand, is produced by continuously pressing the acrylic mass through a mold while the chemical process takes place. As a result, extruded acrylic is heterogeneous and has properties that vary depending on the direction, which is referred to as the extrusion direction.

Cast acrylic is sometimes considered to be of the highest quality, but both cast and extruded acrylic have their advantages and disadvantages—so it is ultimately the application and desired properties of the finished product that determine which is best for your design.

Cast acrylic is available in many colors, while extruded acrylic is often clear (transparent), white, or black. If you order a custom color from us, it will be cast.

In terms of properties, cast acrylic has higher surface durability and is therefore more scratch-resistant and more resistant to chemicals than extruded acrylic.

Cast acrylic sheets have a higher thickness tolerance—a cast 3 mm sheet can vary by +/- 15% in thickness, whereas extruded acrylic varies by +/- 5%. The tolerance for cast acrylic can therefore pose challenges for some designs, such as in relation to joints.

Additionally, cast acrylic has fewer internal stresses than extruded acrylic.

When processing acrylic, cast and extruded acrylic also behave differently.

It is more difficult to bend and shape cast acrylic than extruded acrylic.

When cast acrylic is laser cut, there are almost no burrs, whereas extruded acrylic will have burrs after laser cutting.

The surface engraving of cast acrylic becomes matte white, while that of extruded acrylic becomes matte gray, making it less prominent in the material. Transparent acrylic cannot be engraved with a YAG laser.

There are also differences in polishing between the two types of acrylic. Extruded acrylic can be flame polished, while cast acrylic cannot.

If you are unsure whether to choose cast or extruded acrylic for your design, we are happy to help you.

Acrylic can be damaged by cleaning with alcohol, benzene, or harsh brushes that scratch the surface.

Therefore, acrylic is best cleaned with water, regular dish soap, and a clean, soft cloth that won’t scratch the surface of the acrylic. Acrylic can also be sprayed with glass cleaner (without alcohol or spirits) and wiped down with a soft cloth.

Be aware that excessive mechanical friction with a cloth or other objects against the acrylic can create small scratches, which may dull the shiny surface of the acrylic over time.

By sending us a STEP file or PDF with your drawings, we can quickly help determine if acrylic is the right choice for your project.

We can also identify which processing method is best suited for the item.