While standard PLA excels in ease of printing and aesthetics, its mechanical properties, particularly its brittleness, limit its use for functional parts. This is where PLA+, also known as “Tough PLA,” comes in. It is an improved version that aims to bridge the gap between the easy printability of PLA and the mechanical resistance of materials like ABS or PETG.
What is PLA+ and how does it differ?
PLA+ is not a chemically different polymer, but rather an improved formulation of standard PLA. Its base is still polylactic acid, but during synthesis, manufacturers add special additives and modifiers. These admixtures are designed to specifically improve the mechanical properties of the material, especially its toughness and impact resistance.
The exact composition of these additives is usually a trade secret of each manufacturer, but they often involve various types of impact modifiers, such as acrylic polymers or other elastomers. These substances work at the molecular level by disrupting the brittle structure of pure PLA, allowing the material to absorb more energy before fracturing. The result is a material that tends to bend rather than shatter under stress.
Advantages and Disadvantages
The main reason for choosing PLA+ is its improved mechanical properties, which, however, come with certain compromises.
Advantages:
- Significantly higher toughness: PLA+ is substantially less brittle than standard PLA. Impact strength tests show that it can withstand much greater impacts, which is crucial for functional parts such as brackets, enclosures, or mechanical components.
- Better tensile and flexural strength: Thanks to additives, PLA+ often has higher tensile strength and especially flexural strength. This means it can withstand greater loads before permanent deformation or breakage occurs.
- Improved layer adhesion: Modifiers can also improve the bond between individual print layers, leading to an overall stronger and more durable print.
- Better surface finish: Some manufacturers state that PLA+ produces a smoother and less porous surface, which improves the aesthetic appearance of the print.
Disadvantages:
- Higher cost: The addition of specialized modifiers is reflected in the price. PLA+ is noticeably more expensive than its standard counterpart.
- Potentially more challenging printing: Although still much easier to print than ABS, PLA+ often requires a slightly higher nozzle temperature for proper melting and additive bonding.
- Low temperature resistance: The temperature resistance of PLA+ is generally the same as standard PLA, around 60 °C. For applications requiring higher heat resistance, it is still necessary to opt for materials like PETG, ASA, or ABS.
How much does it cost?
The price difference between standard PLA and PLA+ is significant. While standard PLA can be purchased for as little as 400 CZK per kilogram, the price of PLA+ usually starts around 600 CZK and can reach up to 850 CZK for a 1 kg spool. This surcharge reflects the costs of developing and manufacturing more advanced polymer blends.
Best temperatures and settings for printing
For successful printing with PLA+, it is important not to use a generic profile for standard PLA, but to calibrate for the specific material.
- Nozzle temperature: Most manufacturers recommend a temperature 10-15 °C higher than for standard PLA. The common range is 200–230 °C. A higher temperature is necessary for perfect melting and mixing of additives, ensuring maximum strength and layer adhesion.
- Bed temperature: There are no significant differences here. A temperature of 50–70 °C is recommended to ensure good first layer adhesion.
- Print speed: Some PLA+ filaments, such as eSUN PLA+, are also optimized for high-speed printing. However, in general, a slight reduction in speed compared to standard PLA can contribute to better layer bonding and overall part strength.
Reported problems and their solutions
PLA+ is generally less problematic than standard PLA, primarily due to better layer adhesion, which reduces the risk of delamination. The main challenge is finding the correct printing temperature. If the temperature is too low, the additives may not activate properly, leading to a loss of mechanical advantages and potentially weaker layer bonding. Conversely, too high a temperature can cause excessive stringing or material degradation. The solution is to print a temperature tower (temp tower) for each new type of PLA+ filament and visually and mechanically (by break testing) determine the optimal temperature.
Environmental aspect
The ecological profile of PLA+ is even more complicated than that of standard PLA. While the basic polymer still comes from renewable resources, the added modifiers are synthetic plastics that are not designed for biodegradation under the same conditions. The presence of these additives effectively makes industrial composting of the material impossible, as they would contaminate the resulting compost. PLA+ thus becomes a hybrid material that cannot be recycled in conventional streams, and its only end is landfill or incineration, bringing its ecological footprint closer to traditional plastics.
Surface finishing
Surface finishing procedures for PLA+ are identical to those for standard PLA. Thanks to its higher toughness, it may be slightly more resistant to mechanical sanding, but wet sanding still yields the best results. The material readily accepts fillers, primers, and varnishes, allowing for a high-quality final surface finish.
