Laser cutting plastic: What you need to know 

Laser cutting is a precise and versatile technology that has revolutionised various industries. It utilises a concentrated beam of light, typically a laser, to cut through materials with incredible accuracy. This process offers advantages such as intricate detailing, minimal material wastage, and the ability to work with a wide range of materials, including plastic, making it a popular choice in manufacturing and design. 

A plastic laser cutting machine stands out as a versatile tool for plastic fabrication due to its ability to handle diverse plastic materials with precision. It is capable of cutting, engraving, and marking plastics, allowing for the creation of intricate designs and complex shapes. Whether it’s for prototyping, signage, packaging, or intricate product components, laser cutting has proven indispensable in plastic fabrication. 

Types of Plastics Commonly Used for Laser Cutting 

Acrylic (PMMA): Acrylic is a popular choice for laser cutting and produces clean edges. It is a popular laser-cut plastic for signage, displays, and artistic projects. 

Polycarbonate (PC): Commonly used in producing safety shields, lenses, and machine guards. 

Polyethylene (PE): Commonly used to produce packaging materials, prototypes, and custom components. 

Polypropylene (PP): Often used to laser-cut plastic packaging, automotive components, and medical devices. 

Polyester (PET): Laser-cutting plastic materials like PET are used in industries such as electronics, textiles, and packaging. 

The basics of plastic laser cutting 

Laser cutting begins with preparing the plastic sheet or material to be cut. This involves securing it in place on the laser-cutting bed. Once your material is secure, you input your design file, which serves as a guide for the laser to follow during the cutting process. 

Next, you need to calibrate your plastic laser-cutting machine, setting the focal length and adjusting the laser power and speed settings based on the specific plastic material being used. 

A high-powered laser beam is then emitted from the laser resonator. This laser beam is directed through a series of mirrors or a fibre optic cable to the focusing lens which is then directed onto the surface of the plastic material. The intense heat generated by the laser causes the material to melt, vaporise, or burn away, creating the desired cut or engraving. 

Plastics are more suitable for laser cutting compared to some other materials due to their lower melting point. The precision of laser cutting allows for intricate designs without causing excessive heat damage to the material and, unlike metals, plastics don’t conduct heat as effectively, reducing the risk of thermal distortion during the cutting process. 

Choosing the right plastic for laser cutting 

Some plastics are safer to use with a plastic laser-cutting machine, and some plastics should be avoided completely. 

Plastics that are safe for use include: 

Acrylic (PMMA): Widely used for laser cutting applications, such as signage, displays, architectural models, and artistic projects.  

Mylar (Polyethylene Terephthalate – PET): Often used for stencils, packaging, and film applications.  

Delrin (Polyoxymethylene – POM): A high-performance plastic that is suitable for precision components, gears, and mechanical parts. 

Polyethylene (PE): A versatile plastic used in packaging, containers, and various consumer goods. 

Polypropylene (PP): Used in packaging, textiles, and automotive components. 

Plastics to Avoid for Laser Cutting 

Polyvinyl Chloride (PVC): Produces chlorine gas and releases corrosive hydrochloric acid when cut with a laser, which is harmful to both humans and the laser cutting equipment.  

Acrylonitrile Butadiene Styrene (ABS): Releases styrene gas when laser cut, which can be harmful when inhaled. 

Polycarbonate: Contains bisphenol A (BPA), which can break down and release toxic fumes when exposed to high temperatures. 

Best practices when using a laser cutting for plastic  

When using a laser-cutting machine for plastic, it is crucial to prioritise safety to protect both yourself and the equipment. 

• Ensure adequate ventilation 
• Wear personal protective equipment (PPE) like safety goggles and gloves 
• Keep your workspace clean and hazard-free 
• Ensure that the plastic material you are using is compatible with the laser-cutting process 
• Conduct regular maintenance on your laser-cutting machine 
• Establish clear procedures for handling emergencies and unplanned events. 
• Cutting with a compressor for strong air assist flow can help with certain plastics.

Troubleshooting Common Issues 

Sometimes laser-cutting plastic materials doesn’t go as planned. Here are some common issues and possible solutions. 

Uneven Cuts 

Possible Causes: 

• Misalignment of the laser beam 
• Focal length issues 
• Uneven material surface or warping 

Troubleshooting: 

• Check and realign the laser beam path 
• Verify and adjust the focal length according to the material thickness 
• Ensure the material is flat and properly secured on the cutting bed 

Material Not Cutting Through 

Possible Causes: 

• Insufficient laser power 
• Incorrect focus point 
• Dull or dirty cutting lens 

Troubleshooting: 

• Increase the laser power settings 
• Adjust the focus to the appropriate position 
• Clean or replace the cutting lens regularly 

Burn Marks or Melting 

Possible Causes: 

• Excessive laser power 
• Slow cutting speed 
• Inefficient ventilation 

Troubleshooting: 

• Lower the laser power and increase the cutting speed 
• Ensure proper ventilation to remove excess heat and fumes 
• Optimise cutting parameters for the specific material 

Inconsistent Engraving Depth 

Possible Causes: 

• Uneven material thickness 
• Variation in material composition 
• Focus issues 

Troubleshooting: 

• Use materials with consistent thickness 
• Adjust focus and ensure proper calibration 
• Consider using a raster engraving method for better depth control 

Tips for Maintenance and Upkeep of your Laser Cutter 

• Regularly clean the laser cutter’s optics, including mirrors and lenses, to ensure optimal performance. Use lint-free materials and appropriate cleaning solutions. 
• Periodically check and realign the laser beam path to maintain accuracy. 
• Regularly check and adjust the focus point based on the material thickness.  
• Ensure the ventilation system is functioning correctly to remove fumes and prevent the buildup of harmful particles. Clean or replace filters as needed. 
• Lubricate moving parts, such as rails and bearings, to prevent friction and ensure smooth operation. Follow the manufacturer’s recommendations for lubricants and schedules. 
• Regularly calibrate the laser cutter to maintain accuracy. Check and adjust settings such as power, speed, and resolution based on the specific requirements of the materials being used. 

Conclusion

In conclusion, laser cutting has emerged as a highly precise and versatile technology that is ideal for laser-cutting plastic materials. It offers precision, intricate detailing, and minimal material wastage on materials like acrylic, mylar, and Delrin to name but a few. 

At MaxLaser we have several laser-cutters to choose from such as Thunder Laser, Flux & xTool. You are welcome to browse our selection of high-quality machines. 

Contact our friendly team of experts today and let us help you find the perfect plastic laser-cutting machine that will suit both your needs and your budget. We are here to help you as you embark on a journey of enhanced creativity and productivity in the realm of laser cutting.