What is PLA?
Polylactic Acid (PLA) is a biodegradable thermoplastic polyester derived from renewable resources such as corn starch, cassava roots, or sugarcane. Unlike petroleum-based plastics, PLA is plant-based, making it an environmentally friendly alternative for 3D printing applications.
At the molecular level, PLA consists of lactic acid molecules linked together to form long polymer chains. These polymer chains give PLA its unique properties that make it suitable for 3D printing, including its relatively low melting point and minimal warping during printing.
History of PLA
The story of PLA begins long before 3D printing was invented. In 1932, Wallace Carothers at DuPont first produced a low molecular weight PLA. However, it wasn't until the 1980s and 1990s that companies like Cargill and Dow Chemical developed commercially viable methods for mass-producing high molecular weight PLA suitable for various applications.
PLA's journey into 3D printing began in the early 2000s when the RepRap project (an open-source initiative to create self-replicating 3D printers) was gaining momentum. As consumer 3D printers became more accessible, PLA quickly emerged as a preferred material due to its ease of use and environmental benefits.
By 2010-2012, PLA had established itself as the go-to filament for consumer 3D printing, particularly as MakerBot and other early desktop 3D printing companies standardized on 1.75mm and 2.85mm PLA filament for their machines.
Advantages of PLA for 3D Printing
PLA offers numerous benefits that have contributed to its widespread adoption:
Eco-friendly composition: Being derived from renewable plant sources and biodegradable under industrial composting conditions makes PLA more environmentally sustainable than petroleum-based alternatives like ABS.
Pleasant printing experience: PLA emits a mild, sweet smell during printing, unlike the harsh chemical odors associated with some other filaments. This makes it suitable for home and office environments without specialized ventilation.
Low printing temperature: PLA can be extruded at relatively low temperatures (typically 180-220°C), which means less energy consumption and reduced strain on printer components.
Minimal warping: PLA has less thermal shrinkage than many other filaments, resulting in better dimensional accuracy and reduced likelihood of prints detaching from the build plate during printing.
High print detail: PLA can capture fine details and produces sharp corners and edges, making it excellent for models with intricate features.
Wide color range: Manufacturers offer PLA in virtually every color imaginable, including specialty variants like glow-in-the-dark, metallic, wood-filled, and marble-like finishes.
No heated bed required: While a heated bed can improve adhesion, PLA can often be printed successfully on an unheated build surface, which simplifies printer requirements.
Disadvantages of PLA
Despite its popularity, PLA has several limitations to consider:
Limited heat resistance: PLA begins to soften at temperatures as low as 60°C (140°F), making it unsuitable for applications exposed to heat. A PLA cup left in a hot car, for example, might deform significantly.
Poor UV resistance: Prolonged exposure to sunlight causes PLA to degrade and become brittle over time, limiting its suitability for outdoor applications.
Moisture sensitivity: PLA absorbs moisture from the air, which can lead to popping sounds during printing and reduced print quality. Proper storage in airtight containers with desiccant is recommended.
Brittleness: Compared to materials like ABS or PETG, PLA is more brittle and can snap under stress rather than flex. This makes it less suitable for functional parts that need to withstand mechanical stress or impact.
Limited chemical resistance: PLA dissolves in many common solvents like acetone and ethyl acetate, restricting its use in environments with chemical exposure.
Difficult post-processing: Unlike ABS, which can be smoothed easily with acetone vapor, PLA requires more labor-intensive methods like sanding for smoothing the layer lines.
Slow biodegradation: While marketed as biodegradable, PLA typically only breaks down under specific industrial composting conditions (high temperature and humidity) and may persist for years in a regular landfill or home compost.
3D Printer Requirements for PLA
One of PLA's greatest strengths is its compatibility with even basic 3D printers. Here's what you need to print with PLA:
Extruder temperature capability: The printer must be able to heat its nozzle to 180-220°C, which virtually all FDM printers can achieve.
Cooling fans: Unlike some materials, PLA benefits from active cooling during printing. A printer with a part cooling fan will produce better overhangs, bridges, and fine details with PLA.
Build surface: PLA adheres well to various build surfaces, including:
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Glass (often with hairspray or glue stick applied)
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BuildTak or similar printing surfaces
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Blue painter's tape
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PEI sheets
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Textured spring steel sheets
Heated bed (optional): While not strictly necessary, a heated bed set to 50-60°C can improve first layer adhesion and reduce warping in larger prints.
Enclosed printing chamber (optional): Unlike ABS, PLA does not require an enclosed printing environment and often prints better with good airflow.
Material Properties of PLA
Heated Bed | Not Required |
Bed Temp | 45-60°C |
Extruder Temp | 190-220°C |
Printability | Very Easy |
Density | 1.24 g/cm3 |
Coefficient of Thermal Expansion | 68 µm/m-°C |
Max Service Temp | 52°C |
Durability | Medium |
Stiffness | High |
Ultimate Strength | 65 MPa |
How to Print with PLA - Tips and Tricks
To achieve the best results when printing with PLA, consider these practical tips:
Optimal print settings:
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Nozzle temperature: 190-210°C (start with the manufacturer's recommendation)
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Print speed: 30-90 mm/s (60 mm/s is a good starting point)
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Layer height: 0.1-0.3mm depending on the desired detail level
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Cooling: 100% fan speed after the first few layers
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Retraction: 2-6mm depending on your printer's extruder type
Storage: Keep PLA filament in airtight containers with desiccant when not in use. If filament absorbs moisture, dry it in an oven at around 45-50°C for 4-6 hours or use a dedicated filament dryer.
Common print issues:
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Stringing: Often resolved by adjusting retraction settings or lowering temperature
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Layer separation: Usually due to printing too cold or with too much cooling
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Warping: Typically minimal with PLA but can occur with large flat surfaces
Finishing techniques:
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Sanding (start with 220 grit and work up to 1000+ for a smooth finish)
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Priming and painting (PLA takes paint well after proper preparation)
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Epoxy coating for a glossy finish and additional strength
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Cold welding parts together with PLA solvent or super glue
Environmental Considerations
While PLA is often marketed as an eco-friendly material, the full picture is more nuanced:
Renewable sourcing: PLA's plant-based origins do reduce dependence on fossil fuels compared to petroleum-based plastics.
Carbon footprint: The production of PLA generally has a lower carbon footprint than traditional plastics, though agricultural impacts must be considered.
End-of-life reality: Though technically biodegradable, PLA requires industrial composting facilities to break down effectively. In a standard landfill, it may persist for decades or longer.
Recycling challenges: PLA is technically recyclable but requires specialized facilities. Most municipal recycling programs don't accept it, and mixing it with other plastics can contaminate recycling streams.
Balancing perspective: While not a perfect solution to plastic pollution, PLA represents a step toward more sustainable materials in manufacturing and prototyping.
What is PLA+?
PLA+ (PLA Plus) is an upgraded version of the standard PLA (Polylactic Acid) filament used in 3D printing. It is a modified version of PLA that incorporates additional additives to improve its properties, making it stronger, more durable, and more versatile than regular PLA.
Enhanced Durability: PLA+ is stronger and tougher than regular PLA, making it less brittle and more impact-resistant.
Improved Layer Adhesion: PLA+ offers better adhesion between layers, which results in smoother prints and stronger overall structures.
Higher Heat Resistance: PLA+ has better heat resistance than PLA, allowing it to withstand temperatures of up to 70-80°C before softening, compared to PLA's lower resistance (~60°C).
Better Printability: PLA+ is easier to print than some other materials like ABS, with less warping, good bed adhesion, and less stringing. It often offers a smoother finish and fewer print defects.
Slightly More Flexible: While still a rigid material, PLA+ offers more flexibility than regular PLA, making it less prone to snapping under stress.
Improved Surface Finish: PLA+ typically produces smoother prints with a matte or satin finish (depending on the brand), which can reduce the visibility of layer lines compared to regular PLA’s shiny finish.
Not right for you? Learn about other materials here.
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