The best thing about CNC routers is that they can be used to cut and engrave a wide range of materials besides wood.
For example, acrylic is a commonly used material when making signs and other decorative pieces. In the video below, we show plastic sign making with the SUDIAO vacuum table CNC router.
Even though there are many different kinds of acrylic, we will be referring to the extra hard thermoplastic acrylic in this post. Without further ado, let’s explore the process of cutting acrylic on a CNC machine.
Choosing an Acrylic
With hundreds of acrylic variations including different sizes, shapes, and colors, the first step to creating an acrylic piece is to choose which type you want to work with.
We recommend cast acrylic instead of extruded acrylic because it’s much cleaner to cut through. Extruded acrylic can get gummy during the cutting process.
Clear acrylic is lightweight, shatter-proof, and can be used to create unique pieces of art. If you’ve heard of Plexiglass or Lucite, then you know exactly what we are talking about.
Choosing the Right Bit
One of the most important decisions you will make when cutting acrylic on a CNC router is choosing the correct bit. This step is entirely dependent on what you are hoping to achieve.
A 1/4-inch solid carbide O-flute is a great choice for cutting because it has an up-score that will pull out the chips as the cutting occurs. It prevents plastic chips from building up inside the curve of the cut.
If you want to engrave acrylic, a 60° engraving bit is perfect for V-carving. It has a flat-edge tip that leaves you with a better edge quality than other bits.
Drawing and editing tools allow you to come up with original designs or customize ready-made templates. The numerous toolpath options enable you to customize the settings for drilling, auto-inlays, profiling pocketing, prism carving, fluting, texturing, V-Carving, and so much more.
Cutting Acrylic on a CNC Machine
Now that you've chosen your material, bit, and design, it’s time to get started with the cutting process.
Step #1 - Set the feed-rate according to the size of your bit. The recommended feed-rate for cutting acrylic is generally between 75-300 IPM. Larger bits work well with higher feed-rates, and smaller bits require a lower feed-rate.
Step #2 - Set the RPM. We recommend that you use at least 18,000 RPM to optimize the spindle’s ability to cut through acrylic without melting it.
Step #3 - Set the cutting depth. In general, we recommend that the cutting depth be about 1/2 of the diameter of the bit. This will prevent the bit from breaking.
Step #4 - Make sure that you choose to begin cutting with a ramp. You can choose this option inside the V-Carve Pro software. Going into the acrylic with ramping instead of plunging in will prevent distortion.
Step #5 - Secure the acrylic material to the CNC router table.
Step #6 - Run the CNC router to cut out the acrylic design you want.
Why Use a CNC Router?
If you’re wondering why you’d want to use a CNC router instead of a laser, we’ve got a few reasons for you.
A CNC router cuts much faster than a laser, it can cut through painted materials with no problem, and it is more accurate for engraving and 3D designs. While you can use a laser for acrylic designs, a CNC router offers more versatility overall.