Tips For Using Your CNC Router To Cut Acrylic

Acrylic is a durable, transparent form of plastic and is one of the most popular materials in CNC machining. It offers numerous advantages over other materials like glass and polycarbonate, making it an ideal choice for many industrial applications.

CAMaster CNC routers are fully equipped to cut acrylic sheets. Keep the following tips in mind to help you avoid any irregularities or difficulties during acrylic CNC cutting to maintain a smooth cut. 

Acrylic CNC Machine Setup

While acrylic CNC cutting can be done using standard CNC machines, various considerations have to be made to ensure the machine is able to cut acrylic pieces as precisely as possible with minimal damage. Thus, your CNC router acrylic machine must contain the following:

• A strong, rigid base to support the entire machine during operation.

• Smooth controls and drive system to create precise cuts.

• Helical rack systems to deliver smooth operations.

• A reliable means of clamping to keep the acrylic in place during cutting and reduce vibrations, from a vacuum-hold system to a reliable double-sided tape.

Additionally, the CNC cutting acrylic settings must reflect what you are trying to achieve based on the material being used. As such, it must possess a suitable bit size, flute length, and cutting speed.

Acrylic Selection

Choosing what type of material to work with is another important consideration, as it determines the kind of products you can create and the other machine parts to be used during production.

Generally, acrylic can be categorized into two main types:

• Cast Acrylic

  is known for being rigid, strong, and highly resistant to various chemicals. Available in a wide range of colors and surface texture effects, this type of acrylic is widely used in advertising in the production of large-sized signs and boards.

  
  
  

• Extruded Acrylic

  possesses relatively weaker mechanical properties while being more flexible than cast acrylic. 

Acrylic CNC Machine Considerations

Use A Specialized Bit

Be sure to use a bit specifically designed for cutting acrylic, as standard wood or metal bits won’t do as good a job with chip removal and can cause a rougher cut. You want a bit that can effectively drill holes in acrylic while exhibiting cutting capabilities that align with your end goals.

Generally, a high-quality router bit with an upward spiral, single flute geometry gives the best results on acrylic as it provides a smooth and consistent finish while ensuring optimal chip extraction.

Also, choose the shortest flute length for cutting through the acrylic. Shorter flute lengths reduce cutter chatter and deflection, helping you achieve the best cut quality.

In terms of material, carbide is an excellent choice for acrylic drilling. These bits can usually be found at your local hardware store.

Select A Larger Bit Size

When cutting acrylic, a larger bit size tends to do a better job removing the chips than a smaller one. Try to use the largest bit size possible that is still conducive to your project. As a starting point, a 0.25” bit seems to be workable for most acrylic sheets.

Secure The Acrylic

Acrylic is a soft material that tends to vibrate during cutting. Make sure it’s held down securely when you begin cutting, as too much movement can make your cuts rough and uneven. Use a robust clamping technique combined with rubber pads to ensure the workpiece remains still and firm during cutting and eliminate any risk of scratching on the acrylic surface.

Cut At A Steady Rate

One of the most common issues with using a CNC router to cut acrylic is that when the acrylic heats up due to the friction, the edges of the cut tend to melt and remold, effectively bonding the acrylic back to itself after you cut through it. 

You can minimize the issue by keeping your spindle speed at 18,000 RPM at a recommended feed rate of 75 to 300 IPM. If you’re operating at higher RPMs, you may also need to increase your feed rate to decrease further the contact time between the bit and the plastic. It’s best to cut through the acrylic as quickly and steadily as you can while maintaining control.

Keep The Acrylic Cool

If you are still having problems with the CNC router acrylic re-bonding due to the heat, you may have better luck if you put the acrylic in a freezer for an hour or so before cutting it, so the starting temperature is lower. Feel free to use a cool mister on the plastic and the blade from time to time to moderate the temperature.

Boost Operational Efficiency with CAMaster

CAMaster is committed to helping you get the best use of your router. By following these tips for using your CNC router to cut acrylic, you’ll have better results and an excellent smooth cut. Contact us today to discuss your router needs.