Plastics is one of the most common materials for laser cutting. It is due to its distinctive qualities like lightweight, chemical resistance, and mechanical strength. Many different forms of plastics are available for laser cutting, and each has its special features and advantages. Generally, a laser cuts plastics by melting or evaporating them. It is able to be done with high precision and speed, depending on the type of laser and the type of plastics. There are other aspects to be taken into account. For example, the thickness of the plastic sheets or the type of laser cutter that must be used is important. There are three main types of laser cutting systems: CO2, fiber, and solid-state lasers like the Nd:YAG.
Listed below are the best plastic for laser cutting.
- Styrene: It is a thermoplastic that is able to be cut with a laser, but it needs special techniques to keep it from melting or getting burned.
- Kapton tape: It is a thin, uniform film that is able to withstand high temperatures and is easy to cut with a laser.
- High-density polyethylene (HDPE): It is a thermoplastic that is able to be cut with a laser, but it needs special techniques to avoid problems like melting or charring.
- Polypropylene (PP): It is a thermoplastic that is able to be cut with a laser, but it needs special techniques to keep from melting or burning.
- Polyethylene (PE): It is a thermoplastic that is able to be laser-cut, but it requires specialized techniques to prevent dissolving or charring.
- ABS (acrylonitrile butadiene styrene): It is a uniform and consistent thermoplastic, making it easy to cut with a laser.
- Two-tone acrylic: It is a variety of acrylic that is able to be laser cut with ease due to its uniform thickness and properties.
- Mylar (polyester): Polyester film known as Mylar is thin and homogeneous, making it an excellent material for laser cutting.
- Nylon: It is a thermoplastic that is able to be cut with a laser, but it needs special techniques to keep it from melting or getting burned.
- PETG (polyethylene terephthalate glycol): It is a thermoplastic with consistent thickness and properties that make it easy to laser cut.
- Acrylic: It is a popular material for laser cutting due to its consistent properties and ability to produce clean and precise cuts.
1. Styrene
Styrene or polystyrene (PS) is a kind of vinyl polymer. It is able to be molded under elevated temperatures since it is thermoplastic. PS is often used as thermal insulation material in the construction business. It is able to be easily laser-cut or engraved. The best-suited laser cutter to achieve this is equipped with a CO2 laser. Usually, the output wavelength of such a system is either 9.3 or 10.6 micrometers. A fiber laser, on the other hand, has a smaller wavelength (1.06 microns). This wavelength is not as easily absorbed by the PS. Hence, the laser cutting results are able to not as good as with the CO2 laser. The latter is going to produce smooth cutting edges with high depth. Laser engraving of styrene is possible because the laser beam is able to melt the top layers of the PS.
On the other hand, Polystyrene and styrene are identical plastics. Polystyrene is a polymer derived from the monomer styrene, which indicates that styrene serves as a building component in the production of polystyrene. It is essential to use a laser cutter developed particularly for polystyrene cutting while cutting it. Polystyrene is cut cleanly and precisely using a CO2 laser cutter.
2. Kapton tape
Kapton is a very endurable polymer often used in high-temperature applications or electrical insulation. A 355 nm laser system is ideal for laser engraving or cutting Kapton (or polyimide). The most prominent type for this wavelength is an Nd: YAG laser. It combines high accuracy with fast cutting or engraving capabilities. The best speed is around 12.5 mm/s. An intense laser beam is directed upon the substance in both circumstances. It leads to the evaporation or melting of the Kapton tape. The result is going to be highly precise cutting edges and good reproducibility.
The optimum power, speed, focal length, and airflow level are strongly dependent on the thickness of the Kapton plate that must be cut or engraved. The right laser power is about 30-40 W for cutting and 4-6 W for engraving. The rule of thumb is: The thicker the plate, the higher the laser power and the lower the speed.
On the other hand, Kapton tape and polyimide are similar things. DuPont makes polyimide film tape called Kapton. Kapton tape is a polyimide tape with outstanding thermal and electrical qualities, making it suited for high-temperature situations.
Polyimide cutting is commonly recommended. High accuracy, flawless cuts, and low material waste are just a few benefits that laser cutting has over conventional cutting techniques. Moreover, laser cutting is a non-contact procedure, which reduces the possibility of damage or distortion since there is no physical touch between the cutting tool and the material being cut.
Yet, a few crucial things to remember while laser cutting polyimide. For instance, the material is very heat-resistant. Thus, precise cuts need to be made using a strong laser. Moreover, the material is able to release harmful gases when cut, necessitating adequate ventilation and safety precautions.
3. High-density polyethylene (HDPE)
High-density polyethylene, or HDPE for short, is a thermoplastic material. It is used in a wide variety of applications and products. Examples are plastic bags and bottles, pipes, crates, and toys.A CO2 laser must be used for cutting or engraving HDPE. Its typical wavelengths of 9.3 or 10.6 microns are very well absorbed by the material. One very suitable laser system is the LS series from Boss Laser.
Laser cutting or engraving of high-density polyethylene results in very clean edges. The borders of these cutting edges are not discolored but might have slightly raised borders. The laser power must be relatively low, or the cutting speed must be high since HDPE has a low melting point. Inhomogeneous surfaces and some localized melting are able to arise from improper parameter selection.
4. Polypropylene (PP)
Polypropylene (PP) is one of the most produced thermoplastics on the market. Some widely used brand names are FormexTM and StatexTM. It is white or transparent in color and has excellent chemical resistivity. The melting point is quite high (about 180 °C, or 340 °F). It is able to be used for piping, plastic furniture, and laboratory containers. The best option for laser cutting or engraving PP is a CO2 laser cutting system. This type of laser cutter is pretty common for processing plastics. Low laser power must be utilized for cutting or engraving since PP has a comparatively low melting point. The laser light from a CO2 laser system is able to yield clean and accurate cuts without any discoloring. However, the edges of the cut or engraving are able to be slightly elevated. Too high a laser power lead to local burning or impurities on the material surface.
5. Polyethylene (PE)
Polyethylene (PE) is very similar to high-density polyethylene in terms of physical and chemical properties. This material is able to be neatly cut with a CO2 laser. The process is fast and reliable and yields accurate results. PE absorbs laser light with wavelengths between 9 and 11 micrometers very well, much like HDPE. On the other hand, light from a fiber laser is not efficiently absorbed and must be avoided. The laser power must not be set too high, and the airflow has to be sufficient. The PE surface gets easily damaged or even burnt if this is disregarded. Too much laser power is able to result in inhomogeneities in the cutting or engraving pattern. However, the results are going to be excellent if the laser power and cutting speed are reasonably set.
6. ABS (acrylonitrile butadiene styrene)
ABS is an amorphous thermoplastic, which means it has no real melting temperature. However, it is able to be used for temperatures up to 105 °C (221 °F). It is used in some very peculiar applications. Lego bricks, for example, are made of ABS. ABS powders with grain sizes in the micrometer range are even used as a color basis in the tattoo ink. Larger parts made of ABS are to be found in car parts and musical instruments, or computer cases. Sometimes this kind of plastic is found under the brand names CYCOLACTM or SANTACTM. Laser cutting or engraving acrylonitrile butadiene styrene with a commercial CO2 laser is no problem. For very high laser powers, however, it has to be noticed that the surface can emit carcinogenic fumes (if the temperature reaches more than 400 °C or 750 °F).
7. Two-tone acrylic
Two-tone acrylic is basically like ordinary acrylic but with two colors. Hence the properties relevant to laser cutting or engraving are identical to the ones for acrylic. The most popular lasers for cutting or engraving two-tone acrylic are CO2 lasers. They usually have output powers between some dozen to some hundred Watts. The choice of output power depends on the thickness of the acrylic. The speed of such laser systems starts at around one mm/s and is able to go up to several cm/s. The laser power and workpiece thickness both affect how quickly the process moves. The higher the output power of the laser, the faster it is able to cut or engrave. The laser’s focal length is able to be arbitrarily selected in theory, although for most applications, it is going to be several centimeters. The acrylic needs to be chilled during processing for various applications. This is commonly done with suitable airflow. The flow itself has to be adjusted in accordance with the laser power and the material properties.
8. Mylar (polyester)
The DuPont Corporation owns the brand name Mylar. It is a particular kind of PET that is extruded. Polyester is a very laser-safe material. It typically comes in transparent sheets with a thickness of about some micrometers. It is high tensile strength and chemical stability makes it an excellent electrical insulator.
Mylar typically consists of thin foils, which require little laser power. It must be possible to laser cut the material with 20 to 30 Watts, even at high speeds. However, there are able to be smoke and fumes produced. Consequently, ample circulation or ventilation must be employed.
A CO2 laser or other low-power laser system is a great option for cutting Mylar stencils. It is possible to laser engrave Mylar, although it is uncommon. It is essential to select Mylar plates that are rather thin. Otherwise, the sheet has a tendency to curl and produce bubbles. The greatest thickness must be 1.6 mm.
Moreover, several methods are able to be used for Mylar cutting aside from laser cutting, including scissors or rotary cutter, die cutting, and water jet cutting.
9. Nylon
Nylon belongs to a group of synthetic polymers. Those polymers are made up of polyamides that are linked by so-called amides. It is mostly made from petroleum, has a silk-like structure, and is a thermoplastic. It is mostly known as a kind of synthetic fabric that is used in the clothing industry. However, it is able to be used for food packaging or extruded to form sheets or pipes. Laser cutting or engraving of nylon sheets are able to be done quickly and accurately.
The best choice of the laser cutter is, like most common plastics, a CO2 laser. However, using a fiber laser for Nylon processing is not recommended because the wavelength is shorter than that of a CO2 laser and is not absorbed so well. Nylon engraving and cutting the lead to clean edges with little melting. Thus, it is able to be used for presentation or design parts if needed. The cutting or engraving is going to be very precise and repeatable. Sufficient airflow is necessary for the process. One must pay attention that the airflow covers as much of the workpiece’s surface as possible.
10. PETG (polyethylene terephthalate glycol)
Polyethylene terephthalate glycol is a polymer with excellent chemical and physical properties. It is very chemical resistant and has excellent long-term stability. Furthermore, it has superior mechanical stability and is a good electrical and thermal insulator. PETG is a subclass of polyethylene terephthalate (PET). Thus, the cutting and engraving procedure is quasi-identical to the latter. The best results are able to be obtained with a CO2 laser cutter. PETG is an excellent choice of material for laser cutting and engraving. The process is fast, reliable, and accurate. PETG is a material with an aesthetic appearance. Hence, laser-cut parts from PETG is able to be used for design pieces or decorative items (for example, for a company stand at an exhibition). The cutting/engraving edges of transparent PETG sheets will appear frosted or transparent white. This creates a very nice optical impression for the viewer. This is very relevant, especially for designers and artists. Laser cutters are optimal for these industries because they enable the production of small-batch series or one-of-a-kind items. The time and financial costs are relatively low, while the production speed is high.
11. Acrylic
The most common laser for cutting or engraving acrylic is the CO2 laser. They typically have output powers ranging from tens to hundreds of watts. Output selection depends on the thickness of the acrylic sheet or foil. Such laser systems have velocities starting around one mm/s and up to several cm/s. The actual speed of the process is determined by laser power and workpiece thickness. The higher the laser power, the faster the cutting and engraving. The laser’s focal length, in theory, is able to be adjusted to any value between zero and infinity, but in practice, it often is no more than a few centimeters. Several reasons necessitate cooling the acrylic during processing. This is usually done with adequate airflow. The flow must be adjusted according to the laser power and material properties.
Furthermore, signage, furniture, and automobile manufacturing are just a few sectors that often use acrylic as a plastic material. Aside from laser cutting, various techniques are able to be used for acrylic cutting, including CNC routing, saw cutting, and water jet cutting.
What are the guidelines for laser-cutting plastics?
Laser-cutting plastics are able to be trickier than laser-cutting wood or metal because plastics tend to have a lower melting point and can release dangerous fumes when cut. There are five basic recommendations for cutting polymers with a laser. First, choose the proper kind of plastic for the project since not all plastics are able to be cut with a laser. Certain plastics, such as PVC, emit poisonous gases when cut, while others, such as polycarbonate, break or melt readily. A common material for laser cutting is acrylic, known as PMMA, because of its great optical clarity, low melting temperature, and simplicity of use.
Second, employ excellent ventilation while laser-cutting polymers to eliminate hazardous vapors. Ensuring the air in the workstation is clean and safe to breathe is able to be accomplished with an air purifier or fume extraction equipment. Third, various polymers need different laser settings to cut well. Thicker materials need more laser power, whereas thinner materials need less. Cutting a big piece of material without testing alternative settings is able to lead to poor results.
Fourth, laser-cutting plastics distort and melt, therefore, use a cutting bed that is able to resist heat and pressure. Honeycomb or solid metal beds with non-stick coatings are able to avoid warping and melting. Lastly, dust and debris are able to interfere with the cutting process. Avoid strong chemicals and use a soft cloth and mild detergent to clean the plastic.
On the other hand, a few things must be considered when laser cutting plastics, including the type of plastics, the complexity of the design, safety precautions, and post-processing considerations.
Various polymers have varying melting points and thermal characteristics, therefore, choosing the suitable laser cutter is crucial. CO2 laser cutters are able to cut certain polymers, while others need fiber or UV laser cutters. A CO2 laser cuts acrylic and polycarbonate, whereas a fiber laser cuts polypropylene and polyethylene. Moreover, design complexity is able to influence laser cutting. CO2 laser cutters are able to cut straight lines and basic forms. Intricate patterns or sharp edges need a fiber laser cutter for accuracy. The laser cutter and cutting speed depending on material thickness.
Laser-cutting polymers generate toxic gases and fumes. Use a laser cutter with suitable ventilation and air filtration, and wear gloves, eye protection, and a mask. Furthermore, laser cutting needs post-processing to smooth or polish plastic edges. Sandpaper, polishing wheels, or chemical solvents melt and smooth the edges.
What are the worst plastics for laser cutting?
Plastics are generally excellent materials for tasks requiring laser cutting. However, certain types must be treated carefully or avoided. Some plastic materials that must not be processed with a laser are Polyvinyl chloride, Polyvinyl butyral, and Teflon.
Polyvinyl chloride or Coroplast) releases hydrogen chloride gas, which forms hydrochloric acid with the humidity in the air. They are going to damage the laser in the long run, even the exhaust piping, fans, etc. It is very toxic and dangerous to the body, especially the lungs.
Polyvinyl butyral (PVB) is able to release fumes that damage the laser optics or other parts of the laser cutter. Moreover, Teflon (PTFE) is able to be laser cut or etched theoretically. However, it is not recommended.Teflon is among the materials that are not allowed to be laser cut because it gives off fumes that are able to damage the hardware. COF2, a poisonous gas, is emitted if the laser heats the material over 440 °C.
What materials are not safe for laser cutting?
Listed below are the materials that are not safe for laser cutting.
- Glass: Glass is able to be engraved with a laser, but it is impossible to cut through it entirely. The engraving process achieved is due to micro-scratches and cracks on the surface of the glass, but laser cutting it is not able to yield any good results.
- Painted materials: Technically, the laser is unable to cut or engrave the paint but evaporates it and cuts/engraves whatever is below it. Many paints contain ingredients that must not be heated or evaporated because they are potentially toxic. Thus, don’t use the laser cutter on such surfaces.
- Mirrors: It makes no sense to use mirrors for laser cutters that use visible light. However, CO2 laser radiation is able to penetrate the glass in front of a mirror and is going to damage the thin metal layer (often silver) that makes the mirror reflective. This is going to ruin the whole thing.
- Fiberglass: Theoretically, it is possible to cut/engrave fiberglass with a CO2 laser, but specific components emit hazardous vapors during the process. Some of these vapors are highly poisonous.
Is plastic easier to laser cut plastics than wood?
No, cutting wood is as easy as cutting plastics with a suitable laser cutter. The only caveat is that the maximum thickness for laser cutting wood is around 30 mm. The reason for this is that wood absorbs laser radiation efficiently. The upper layer of the timber becomes black and charred during this process. The blackened wood absorbs even more laser power, and the wood is going to start burning at some point. This limits the laser cutting to the aforementioned thickness of the wood. Otherwise, a good laser-cutting system is not going to make any difference between wood and plastics.
However, The best materials for laser cutting vary depending on the material since each has unique features and characteristics that influence the laser cutting process. For example, wood is generally better for laser cutting than plastic.
Birch, maple, cherry, walnut, and bamboo are some of the best woods for laser cutting when it comes to materials. These woods have a low resin and moisture content, reducing warping and charring when cut with a laser. They are excellent for a variety of laser-cutting applications because they have uniform grain patterns and are simple to engrave or etch.
On the other hand, acrylic, polycarbonate, and ABS are the best plastics for laser cutting. These plastics have low melting points and little thermal expansion, making clean, accurate cuts possible. They are safe to use in a number of applications since they do not emit any dangerous fumes or smoke while the laser-cutting process is being done.