Besides the main categories, there are several other specialized PLA filaments on the market that offer unique properties for specific purposes. Among the most interesting are glow-in-the-dark materials and ultra-light foaming filaments.
1. Glow-in-the-dark PLA
This filament is popular for making decorations, toys, and Halloween accessories that glow in the dark after being illuminated.
- Composition and Principle: The base is PLA, mixed with phosphorescent pigments. Strontium aluminate is most commonly used, which can absorb energy from UV radiation (sunlight, UV lamp) and then slowly release it in the form of visible light. This material glows much brighter and longer than older zinc sulfide-based pigments.
- Abrasiveness and Hardware Requirements: A key property that many users underestimate is the high abrasiveness of this material. Strontium aluminate is a very hard, ceramic-like material. Printing with this filament is equivalent to pushing fine sandpaper through the nozzle. This leads to very rapid wear of standard brass nozzles, which manifests as degraded print quality and loss of accuracy. For any, even occasional, use of glow-in-the-dark filament, it is therefore strongly recommended to replace the nozzle with a hardened steel nozzle.
- Print Settings: Print parameters are very similar to standard PLA. However, to achieve maximum luminescence, it is advisable to adjust the slicer settings so that the part contains as much material as possible. It is recommended to increase the number of perimeters (walls) and use a higher infill density. Thin-walled or hollow models will not glow as intensely because they contain less active pigment.
- Price: The price is slightly higher than standard PLA, typically ranging from 600–900 CZK per 1 kg.
- Surface Finish: Usually not necessary, as the main goal is to preserve the surface’s luminescence.
2. Lightweight (LW-PLA) / Foaming PLA
LW-PLA is a revolutionary material designed primarily for the RC aircraft and drone building community, where every gram of weight is critical.
- Composition and Principle: LW-PLA contains a special foaming agent that is activated by heat. When a certain temperature is reached in the nozzle (typically around 230 °C), this agent begins to decompose and release gas (e.g., CO2). This gas creates millions of microscopic bubbles in the extruded material, similar to yeast in dough. Thanks to this foam structure, the material’s volume can increase up to three times, leading to a dramatic reduction in the density and weight of the final print – up to 65% compared to standard PLA.
- Settings and Calibration: Printing with LW-PLA requires an active approach and calibration, as the final properties of the part are directly controlled by the print settings.
- Density Control by Temperature: The degree of foaming, and thus the density and weight of the part, is directly dependent on the nozzle temperature. A lower temperature (e.g., 210 °C) means minimal foaming, and the part will be almost as heavy as regular PLA. A higher temperature (e.g., 250 °C) activates maximum foaming and leads to the lightest possible part.
- Flow Rate Calibration: Because the material expands in the nozzle, it is necessary to radically reduce the material flow rate (flow rate or extrusion multiplier) in the slicer, often down to 40–60% of the original value. Without this adjustment, the print would be massively over-extruded and dimensionally inaccurate.
- Calibration Process: Manufacturers like Colorfabb recommend a specific calibration procedure: first, print test cubes at various temperatures (e.g., from 200 °C to 280 °C) with 100% flow rate to determine at which temperature the greatest expansion occurs. Then, at this optimal temperature, print more cubes with gradually decreasing flow rate until the wall thickness of the cube matches the nozzle diameter. This finds the correct flow rate value for the given temperature and speed.
- Applications: Thanks to its extremely low weight, LW-PLA is ideal for manufacturing parts for RC aircraft, drones, gliders, and other aerial models. It is also used for cosplay props and costumes where large but lightweight parts are needed.
- Price: This is a highly specialized and premium material. The price is around 1100 CZK for a 750g spool.
Series Conclusion: How to Choose the Right PLA for Your Project?
We have explored the fascinating and diverse world of PLA filaments, from the ubiquitous standard to highly specialized composites. It is clear that PLA is no longer just one material, but an entire family of polymers, each offering a unique set of properties. The correct filament choice is often a decisive factor for project success. The following framework will help you navigate this wide range of options:
- For Visual Prototypes, Decorations, and Toys: If your main goal is aesthetics and you don’t need high mechanical resistance, you have several options.
- Standard PLA: It is the most affordable, easy to print, and offers a huge range of colors. It is an ideal choice for quick prototypes and general prints.
- Silk PLA: If you want your print to truly shine, opt for silk PLA. Its glossy surface is unparalleled for vases, figurines, and artistic objects. However, be prepared for more demanding print tuning.
- Matte PLA: For an elegant, professional, glare-free look, matte PLA is the perfect choice. It excels at hiding layers and is an ideal base for painting.
- For Functional Parts and Mechanical Components: When you need a part to withstand something, standard PLA is not enough.
- PLA+ (Tough PLA): It is the clear choice if you need a part resistant to impacts and bending. Ideal for brackets, covers, gears, and other components that will be subjected to mechanical stress, but not high temperatures.
- Carbon Fiber PLA (PLA-CF): If maximum stiffness and minimum weight are key parameters, PLA-CF is unparalleled. Perfect for drone frames, RC model parts, and jigs that must not flex. However, remember the necessity of using a hardened steel nozzle.
- For Artistic Projects with Unique Texture and Weight: If you want to create something that looks and feels like it’s made from another material, choose composites.
- Wood PLA: For the look and feel of wood. Be prepared for intensive post-processing (sanding, staining), which is key to a realistic result. A hardened nozzle is also necessary here.
- Metal PLA: For heavy, metallic-looking figurines and replicas. Post-processing is the alpha and omega of the entire process here – without it, the part will remain just a dull piece of plastic. A hardened nozzle is an absolute must.
In conclusion, two universal truths that permeate the entire series must be reiterated. Firstly, any filament containing solid particles (wood, metal, carbon fibers, glowing pigments) is abrasive and requires the use of a hardened steel nozzle. The investment in it is small compared to the frustration of constant problems and ruined equipment. Secondly, the ecological benefit of PLA is complex, and its “biodegradability” is conditional on industrial composting, which is unavailable to most users.
The world of PLA is a constantly evolving field full of innovations. Do not be afraid to experiment, test new materials, and share your experiences with the community. Only by doing so can the enormous potential hidden within this diverse family of filaments be fully uncovered and utilized.
