Polystyrene (PS) Laser Engraving and Cutting (Styrofoam™ Laser Cut)
Learn more about laser engraving with this material and its different settings.
Polystyrene laser cutting and engraving refer to the process of cutting various 2-dimensional profiles from polystyrene sheets using a laser cutter. Styrofoam™, a DuPont brand name for extruded polystyrene (XPS) is a rigid thermoplastic that is extruded into sheets or other complex cross-sections.
Polystyrene is relatively easy to cut but can be prone to catching fire if the incorrect settings are used. As such, it is best to start with low-power and high-speed settings and then optimize these for the specific polystyrene being cut. A speed of 200 mm/s with a power rating of 10 W is recommended as a start. A typical extruded Styrofoam™ sheet is shown in Figure 1 below:
Example of Extruded Styrofoam.
Image Credit: Shutterstock.com/irin-k
Polystyrene can be easily cut using relatively low wattage CO2 and diode laser cutters, i.e., less than 20 W. This is due to polystyrene’s low melting point of 230°C and low density of 0.035 g/cm3. The general process for laser cutting polystyrene is listed below:
- Convert the design to vector format. The conversion to vector format can be done with free software such as Inkscape. If possible, use designs that already come in vector format, i.e., with an SVG file extension. This file extension makes it easy to convert the edges into paths for the laser cutter to follow. Alternatively, use a CAD program like AutoCAD® to design the profile of the part to be cut. Most laser-cutting machine software will accept the standard .dxf file format generated by AutoCAD®.
- Select the correct polystyrene sheet thickness based on the available machine power. Polystyrene can easily melt, so the power must be carefully selected. Set the machine to a low power at first if unsure. Polystyrene foam can be purchased in different densities, and a higher density will require a more powerful laser setting.
- Secure the polystyrene sheet to the base of the machine's cutting bed. Polystyrene is light and can be secured with double-sided tape. Once cutting is complete, the sheet can be removed and is ready for use.
While polystyrene can be laser engraved, the process generally produces insufficient contrast, making the engraved images almost invisible.
Styrofoam™ sheets can be cut in a number of different ways in addition to laser cutting. A hot wire cutter is a manual method that is often used to cut Styrofoam™ and produces a clean edge. However, to get good results the cutting speed must be properly controlled when pushing the sheet through the hot wire. This is especially effective for thicker sheets. For thin sheets, a simple scalpel blade and a ruler can be used to cut shapes.
Polystyrene is not cast; it is only extruded into sheets and formed into custom shapes in the case of expanded polystyrene. In addition to this, polystyrene can be engraved, but there is no contrast as the polystyrene does not discolor when melted with the laser. This makes it unsuitable for laser engraving
Yes, polystyrene is easy to cut using a variety of cutting tools like a hot wire cutter or a saw, for example. In addition to this, its low melting point makes it easy to laser cut as well.
The difference between the general part and the presentation part cutting of polystyrene is the level of detail on the edges of the cut part. General parts are not required for aesthetic purposes; examples include insulation that will be hidden from view. Presentation parts, on the other hand, need to have clean-cut edges and look presentable as these are used for aesthetic applications like signage or decorations.
Polystyrene has a few advantages that make it ideal for laser cutting, some of which are listed below:
- Low Power Requirements: Polystyrene has a low density and melting point, which makes it easy to cut with low-power, entry-level laser cutters.
- Low Cost: Polystyrene is relatively low cost, making it an ideal material for creating large items like props or signs.
Despite the advantages, laser cutting polystyrene does present some disadvantages as listed below:
- Flammable: Polystyrene is often listed as the number-one cause of fires in laser cutting machines. It is highly flammable. As a result, the use of incorrect settings can quickly cause burning which will destroy the laser cutter.
- Low Melting Point: Polystyrene has a low melting temperature and as such will melt when exposed to the heat from the laser. This has the effect of producing a wide cutting line and can also cause irregularities in the cut edge.
The best type of polystyrene for laser cutting is extruded polystyrene (XPS). There are generally three types of polystyrene, namely: HIPS (High-Impact Polystyrene), EPS (Expanded Polystyrene), and XPS (Extruded Polystyrene). HIPS behaves similarly to other rigid plastic sheets as it is not a foam but rather a solid thermoplastic with a density of 1.05 g/mm3. It does not cut as easily as XPS in the same thickness. Laser cutting of EPS should be avoided as the small balls that it is made up of could come apart on the edges, producing a poor finish. XPS is a closed-cell foam that is not made up of small balls and as such maintains its edge after being cut.
Yes, lower-density XPS can be cut at higher speeds and lower power when compared to higher-density XPS. High Impact Polystyrene (HIPS) is also dense and requires higher power and a lower cutting speed to cut effectively.
The best speed for cutting polystyrene presentation parts depends on the thickness and density. For presentation parts, it is important to have a clean and crisp cutting edge. To achieve this with thicker, dense sheets, a higher power with a slower speed is needed. For thicker, less dense sheets, high speeds and low power is ideal.
For general-use parts like insulation panels, the parts can be cut with higher speeds and high power. This may cause some melting on the edges but will not affect the performance of the part.
In general, thicker sheets will require higher power for the beam to cut effectively. However, polystyrene sheets can be produced at different densities; therefore cutting two sheets of the same thickness may need different wattages. Higher density requires higher laser power to cut, for example. It is critically important to note that polystyrene will catch fire easily. Typically, at some point, the polystyrene will catch fire before the laser has a chance to cut through. Multi-pass cutting can be attempted to mitigate this risk, but it is recommended to test this on a small piece before committing to cutting a full part.
The best laser-cutting polystyrene setting depends on the thickness and density of the sheet being cut. It is recommended to test a small block of the material being cut to find the optimal settings before setting out to cut the part. Listed below are some example settings based on a paper-covered foam board of 4.78 mm (3/16”):
- Speed: A 4.78 mm sheet must be cut at 200 mm/s.
- Power: A 4.78 mm sheet must be cut at 10 W.
While polystyrene cuts relatively easily when compared to other thermoplastics, there are some common mistakes that should be avoided. These are listed below:
- Ignoring Flammability: Polystyrene can spontaneously ignite at a temperature as low as 327 °C. A high-powered laser beam that is moving too slowly through the material can easily cause the material to catch fire.
- Setting a Slow Cutting Speed: If the cutting speed is set too slow, there is a chance that the edges will melt, resulting in a wide kerf and a less-than-ideal cut surface.
- Using the Incorrect Focal Length: The focal distance is especially important when cutting thick sheets. The beam is focused to a point, with the laser width being wider before and after this point. If the focal point is too low, the cut will be thicker at the top, and if it's too high the cut will be wider at the bottom of the sheet.
Polystyrene engraves relatively easily. However, no contrast is created as the polystyrene does not discolor during engraving. As such, additional coloring may be required to get the desired effect. Below are additional beginner tips for laser engraving polystyrene:
- Engrave a Test Piece: Before engraving polystyrene sheets, it is recommended to first engrave a sample piece to test the optimal settings. Keep an eye on (with eye protection) the part during this testing to make sure nothing goes wrong.
- Create a Contrast: While engraving does not produce a contrast, it may be possible to laser cut the desired shape out of a very thin polystyrene sheet. Stick this on top of a colored material to get the desired contrast. Alternatively, decrease the speed or increase the power to create a deep, debossed engraving which will provide better contrast when compared to surface-only engraving.
Most entry-level lasers will be able to cut Styrofoam™. This includes CO2 lasers as well as diode lasers. Some common examples are listed below:
- Glowforge: The Glowforge is a popular CO2 laser cutter for entry-level applications and is more than capable of cutting polystyrene.
- xTool D1 Pro: This laser cutter makes use of a diode laser with the option of selecting a 10 or 20-W laser.
- OT-CD: This is a more advanced CO2 laser cutter that is also capable of cutting denser and tougher foams like polyurethane or EVA (ethylene-vinyl acetate). The laser power can be selected as 60, 80, or 100 W.
Examples of polystyrene projects are:
- Tool holders
- Thermal insulation
- Architectural modeling
- Prototyping new designs
- Product packaging
- Theater props
- Art installations
In terms of foam, there are a number of alternatives to polystyrene as listed below:
- PUR: Expanded polyurethane is a tough, closed-cell foam that can be laser cut relatively easily.
- Cork: Cork is a natural material that typically comes in thin sheets. Cork is soft and can serve as a renewable, natural alternative to thermoplastic foams. Learn more in our guide on Laser Engraving and Cutting of Cork.
- EVA: Ethylene-vinyl acetate has many of the same advantages as polystyrene but is not as flammable and is generally tougher.
Laser cutting plastics and natural materials can generally be done with low-powered laser cutters. Some popular materials are listed below:
This article presented polystyrene laser cutting, explained what it is, and discussed the various applications of this laser cutting method. To learn more about polystyrene laser cutting, contact a Xometry representative.
Xometry provides a wide range of manufacturing capabilities, including sheet cutting and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.
- Styrofoam™ is a trademark of DuPont.
- AutoCAD® is a registered trademark of Autodesk, Inc., and/or its subsidiaries and/or affiliates, in the United States.
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