The Complete Guide to Laser Cutting Acrylic with Ease

Acrylic, also known as Plexiglas, has become an incredibly popular material for laser cutting. With its high strength, transparency, and versatile applications, acrylic offers many benefits for laser cutting projects. However, cutting acrylic with a laser requires specific techniques and settings to achieve clean, polished edges.

This comprehensive guide will provide everything you need to know about laser cutting acrylic. We’ll cover how it works, ideal laser cutter settings, edge finishing techniques, applications, and pro tips for success. By the end, you’ll be fully prepared to start laser cutting acrylic with professional-grade results.

How Does Laser Cutting Acrylic Work?

Laser cutting utilizes a high-power, focused laser beam to melt and vaporize material away. For plastics like acrylic, the laser beam heats the material to its melting point before blowing away the melted material with an assist gas. This leaves behind a clean, polished edge on the acrylic.

CO2 lasers with wavelengths between 9.4-10.6 microns are typically used for cutting acrylic. This infrared wavelength is readily absorbed by plastics, allowing the laser beam to efficiently melt through the material.

The laser beam is focused down to a very small spot size, often 0.1 mm or less. This concentrated energy achieves the high temperatures required to melt and vaporize the acrylic.

During the laser cutting process, vectors define the path where the laser will cut through the material. Acrylic can be cut all the way through, or engraved to various depths by adjusting the laser settings and vectors.

Best Laser Cutter Settings for Acrylic

Cutting acrylic requires balancing laser power, speed, and frequency to melt the edges cleanly without scorching or combustion. Here are the ideal laser cutter settings to use when cutting acrylic:

• Laser power: Low-to-moderate laser power between 10-50% is ideal for acrylic. This prevents overheating while still melting the edges effectively.
• Cutting speed: Acrylic responds best to moderate cutting speeds between 10-30 mm/s. Faster speeds can crack or melt the acrylic unevenly.
• Frequency: Higher frequencies between 25-100 kHz produce better edge quality on acrylic. Lower frequencies can cause a striated edge.
• Number of passes: For thicker acrylic, multiple passes with lower power allows heat to gradually penetrate the material for better edge finishes.
• Assist gas: Using compressed air helps vaporize the melted acrylic and prevents scorching. Nitrogen also works well as an inert assist gas.
• Focus: Keep the focus distance normal or slightly above the acrylic surface to create a wider kerf and improved edge finish.

Most laser cutters have presets for cutting acrylic that provide good starting points for these settings. From there, you can fine tune the settings to match your specific laser cutter, acrylic thickness, desired cut quality, and application. Cutting test strips helps dial in the ideal settings.

How to Finish Laser Cut Acrylic Edges

One of the appeals of laser cutting acrylic is achieving a polished, flame-like edge finish. This occurs when the laser melts the edge just right during cutting.

However, some settings and acrylic thicknesses can produce edges with striations or inconsistencies. Here are some techniques to improve edge finishing:

• Flame polishing – Running a small flame over the cut edges reflows the acrylic for an ultra-smooth finish. Take care not to over-heat and warp the acrylic.
• Sanding – Light sanding with fine grit sandpaper or emery boards can smooth out any striations or dross.
• Solvent polishing – Dipping edges in a solvent like dichloromethane evaporates microscopic ridges, improving clarity. Use proper ventilation.
• Laser polishing – Making a slow second pass along the cut edges at low power reflows the surface for polished edges.

Having the right laser cutter settings dialed in will minimize the need for additional edge finishing. But when necessary, these techniques can take acrylic edges from good to perfect.

Best Applications for Laser Cut Acrylic

Thanks to its transparency, rigidity, and polished edge finish from laser cutting, acrylic suits many different applications:

• Signs and displays – Laser cut acrylic has long been used for business signs, awards, and displays that take advantage of its clarity and laser-cut polish.
• Lighting and lamps – Lighting fixtures and lamp shades benefit from laser cut acrylic for its ability to transmit and diffuse light beautifully.
• Partitions – Acrylic sheets make great see-through partitions and dividers when laser cut to size and shape.
• Engraving – Laser engraved acrylic provides a nice contrast between the frosted engraving and transparent background.
• Model building – Architects, engineers, and hobbyists use laser cut acrylic to construct detailed scale models and prototypes.
• Jewelry – Acrylic’s rigidity and optical clarity make it well suited for laser cutting jewelry pieces and embellishments.
• Crafts – Many crafters laser cut acrylic for paperweights, ornaments, keychains, and home decor items.
• Electronics enclosures – Laser cut acrylic boxes and cases look sleek while providing protection for electronics projects.

Acrylic’s aesthetic appeal and customization capabilities make it the go-to material for laser cutting applications both big and small. The opportunities are nearly endless with acrylic and a laser.

Acrylic Laser Cutting: 7 Pro Tips for Better Results

Follow these professional tips when cutting and engraving acrylic to get the best edge quality, precision, and project results:

1. Choose the right acrylic

Not all acrylics are created equal when it comes to laser cutting. Cast acrylic sheets produce the best results. Extruded acrylic tends to crack more easily. Copolymer acrylic also works slightly better than homopolymer.

2. Remove the protective film

Peel off any plastic protective film before laser cutting acrylic. Leaving it on can cause undesirable melting, burning, or marking from the laser beam.

3. Use cutting grids

Metal cutting grids lift acrylic off the work bed and improve airflow, preventing melting during cutting. Great for intricately cut parts.

4. Apply masking tape

Adding strips of masking or painter’s tape to the front side before cutting can prevent scorching by absorbing excess heat.

5. Cut painted side up

If laser cutting acrylic with one painted side, cut with the painted side face up. This avoids paint melting into the back side of cuts.

6. Clean regularly

Keep your laser bed and optics clean to maximize laser efficiency and acrylic cut quality. Remove any acrylic dust buildup regularly.

7. Ventilate properly

Have adequate ventilation and filtration to remove fumes when laser cutting acrylic. Acrylic dust also requires proper disposal.

What Thickness of Acrylic Can be Cut with a Laser?

One of the advantages of lasers for cutting acrylic is their ability to cut a wide range of material thicknesses. Today’s laser cutters can reliably cut acrylic from as thin as 1 mm up to 19-20 mm thick.

Thinner acrylic sheets around 1-3 mm are easiest to laser cut, requiring lower power settings. As acrylic thickness increases, more laser power and slower speeds are needed to cut through the material.

For acrylic around 6-10 mm thick, lasers in the 40-60 watt range have the best balance of power and precision. Industries uses high-power 100+ watt lasers to cut and engrave 19-20 mm acrylic up to 1 inch thick.

No matter the acrylic thickness, following the proper laser settings, techniques, and cut order helps ensure clean cuts without charring, melting, or heat damage. With the right laser cutter, focus lens, and patience, almost any reasonable acrylic thickness can be laser cut successfully.

What Laser Wattage is Required for Cutting Acrylic?

The type of laser cutter required depends on the acrylic thickness to be cut:

• Thin acrylic (<6mm) – Lasers as low as 20-30 watts can handle thin acrylic sheets and hobbyist projects.
• Medium acrylic (6-12mm) – A 40-60 watt CO2 laser cutter provides the best balance of power and control for typical acrylic sheets.
• Thick acrylic (12-20mm) – Cutting thick cast acrylic requires an industrial 100-watt+ laser for efficient absorption and cutting speed.

Higher wattage lasers allow faster cutting speeds and intricate designs even in thick materials. But they require more stringent safety measures. For occasional acrylic cutting, a 30-60 watt hobby laser cutter provides sufficient power without as much complexity.

Laser cutters in this power range have high maximum cut thickness capabilities, but you’ll achieve the best results staying within the recommended acrylic thickness ratings. Match the laser’s abilities to the type of projects you’ll be cutting.

Laser Cutter Brands for Cutting Acrylic

Today’s laser cutter market offers many excellent options for cutting acrylic. Some notable laser cutter brands include:

Epilog – Epilog is one of the most trusted names in lasers, known for their high quality CO2 laser cutters. Models like the Fusion Pro and Legend series are ideal for acrylic.

Trotec – Another industry leader, Trotec’s Speedy line provides robust acrylic cutting with high speeds and accuracy. The Trotec SP1000 is a popular acrylic laser.

Glowforge – For small businesses and hobbyists, Glowforge offers automated acrylic laser cutting in a compact package needing no special exhaust.

OMTech – OMTech builds affordable Chinese fiber lasers that reliably handle acrylic, including the OMTech 40W CO2 Laser Cutter.

Boss – Well-known for dependable workhorse lasers, Boss laser cutters like the LS-1416 can cut and engrave acrylic in all shapes and sizes.

Thunder Laser – Thunder Laser’s Nova and Atom series provide robust acrylic cutting at lower price points for small shops and makers.

Do your research to find a laser cutter suited to your budget, work environment, and projects. Cutting small acrylic pieces has vastly different needs than industrial-scale laser cutting.

Is Acrylic Safe to Laser Cut?

Laser cutting acrylic is safe when proper precautions are taken. Like other plastics, acrylic gives off potentially harmful fumes when vapourized by the laser. Acrylic particles and dust require ventilation and filtration.

Here are some acrylic laser cutting safety tips:

• Always cut acrylic in a well-ventilated area with particulate and fume filtration.
• Wear safety glasses to protect eyes from reflected laser beams and debris.
• Clean the laser system regularly to minimize buildup of acrylic residue.
• Dispose of acrylic dust and pieces safely and responsibly.
• Keep fire extinguishers nearby due to potential for flare ups.
• Never leave the laser cutter unattended when operating.

Acrylic itself has low toxicity. With proper ventilation, filters, and safety practices, laser cutting acrylic poses little hazard beyond other common manufacturing processes. Still, take care to minimize exposure when working with all laser cut materials.

Acrylic vs. Glass for Laser Cutting

When a transparent, polished material is needed for laser cutting, acrylic and glass are two main choices. Here’s how they compare:

Cutting Ability – Acrylic is easier for lasers to cut through cleanly than glass. Glass tends to crack or shatter when cut or engraved.

Edge Finish – Laser cut acrylic has a flame-polished edge unmatched by glass. Glass edges are prone to chipping and sharpness.

Safety – Acrylic produces some potentially irritating fumes during cutting, while glass particles pose a hazard. Air filtration is recommended for both.

Strength – Acrylic is half the weight but nearly as strong as glass. It also tends to resist breaking and splintering versus glass.

** optic clarity** – Glass has the highest optical clarity, but acrylic also transmits light very well for most applications.

Cost – Acrylic is the more budget-friendly option. It machines faster than glass, reducing laser cutting time and cost.

For most uses, acrylic represents the best all-around option thanks to its strength, clarity, cutability, and polished edges from laser cutting. However, glass may be required for specialized optical applications.

Laser Cutting Acrylic: Getting Started

Now that you have a full overview of successfully laser cutting acrylic, it’s time to put this knowledge into practice.

Follow these steps when taking on your first acrylic laser cutting projects:

• Purchase cast acrylic sheets in the desired thickness. Have some scrap pieces to test with.
• Program your design in vector-based laser cutting software like Adobe Illustrator or CorelDRAW.
• Set up your laser cutter with proper ventilation and an air assist nozzle.
• Start with lower power settings on scrap acrylic to find the ideal cutting parameters.
• Use a grid table or acrylic risers if cutting many small detailed pieces.
• Focus the laser properly on the acrylic surface before running jobs.
• Finish edges as needed with sanding, flame polishing, or laser polishing techniques.
• Safety first! Wear goggles, point exhaust at the cut, and never leave the laser unattended.

With some practice using the techniques covered here, you can achieve professional acrylic cutting results. Laser cut acrylic opens up vast possibilities for creative projects and innovative applications.

Acrylic has cemented itself firmly among the most popular laser cutting materials. This comprehensive guide provides everything you need to know about successfully laser cutting acrylic for your specific needs. Use these pro tips and tricks to get the finest cuts with polished edges every time.