Cutting tools | Top tips for cutting Perspex (acrylic)

20 January 2016
 Categories: Industrial & Manufacturing, Blog


Many a time, machinists get it wrong when cutting acrylic or perspex. They experience all manner of problems including melting, chipping and failing to achieve clear smooth edges. But that's going to be a thing of the past. Cutting acrylic is not as easy as wood, but that's only because there are some minor factors you need to consider. Acrylic is plastic, so cutting it requires a different mindset. But once you get a hang of it, you'll be cutting acrylic like you've done it all your life. Here are some classic tips to help you out with your cutting.

Secure it down well

One of the ways that can leave a marred finish is not securing the acrylic material well enough. Any slack would make it vibrate as it's being cut, and this is what brings up the flawed finish. Lay the acrylic on a sacrificial board and place double sided tape on the back. Spray adhesives are also a good option in keeping the material tightly secured. However, when using spray chemicals, ensure they don't contain chemicals such as acetic acid or ammonia that may harm the acrylic.

Leave the cover on

As much as acrylic sheets are hard to break, they can scratch fairly easily. That's why these sheets normally have a protective covering on them. When doing your cutting, don't get rid of the covering; it won't really affect your project if your tools are sharp. When cutting for some sensitive applications like show vehicles, you could leave the covering on even after you're done. Only remove when installing them.

Choose the right bits

Acrylic differs from wood, so you won't be doing yourself any favours if you use wood cutting bits. With acrylic, the chip removal and cutting are very important so you may want to use sharper bits. Actually, using bits that are not sharp enough can cause melting of the plastic. Some of the best bits to use for acrylic are solid carbide tipped or carbide tipped bits.

Also go easy on the plastic, don't try to bite off more than you can chew. Trying to cut too much material also causes melting as the heat dramatically increases. Try cutting within 3 millimetre of the desired finish.

To prevent chipping, keep the bit and cut edge in contact, and don't break contact. Chipping is simply the break of material at the cutting line. Most people break contact and when they quickly push the router back, the cutter chips out the acrylic.