When choosing the best material for our 3D printing projects, PLA and TPU are two popular options, but the differences between them should not be overlooked.
PLA is relatively hard but also brittle, making it suitable for decorative items, prototypes, and educational models that do not need to withstand significant force.
In contrast, TPU is a highly elastic and wear-resistant material, excelling in applications that require impact resistance or repeated deformation.
In the following content, we will delve deeper into the differences between the two materials, presenting a PLA vs TPU showdown to help you make a more informed material choice for your project.
What Is Polylactic Acid (PLA)?
PLA primarily originates from renewable plant resources such as corn starch, sugarcane, or cassava, produced through fermentation and polymerization processes. This makes PLA a truly bio-based plastic.
PLA has a low melting point and good layer adhesion, making it suitable for use in fused deposition modeling (FDM) 3D printing technology.
Due to its rigidity and relatively high strength, PLA is commonly used for decorative prints, prototype models, and educational projects. Additionally, PLA can biodegrade under industrial composting conditions, reducing its environmental impact.
However, PLA has poor heat resistance, typically softening at around 50-60 degrees Celsius, making it unsuitable for high-temperature environments or functional components that require withstanding significant mechanical stress.
Its brittleness also limits its performance in applications involving repeated bending or shock absorption.
Nevertheless, PLA’s low printing temperature, stable print quality, and lack of irritating odors make it an ideal durable material for 3D printing beginners and educational purposes.
What Is Thermoplastic Polyurethane (TPU)?
TPU, or thermoplastic polyurethane elastomer, is an elastic material composed of polyurethane or its derivatives.
This composition gives TPU material excellent wear resistance, a wide range of hardness, and high mechanical strength.
It combines the elasticity of rubber with the processability of plastic and has greater adhesion compared to rigid materials like PLA and PETG.
These unique properties make TPU widely used in various fields, including automotive parts, shoe soles, and electrical cables.
Currently, TPU is primarily used in low-end consumer products, while its high-end applications are largely dominated by multinational corporations, making it one of the fastest-growing thermoplastic materials.
PLA vs TPU: Material Properties
PLA filament and TPU filament are two of the most common materials used in 3D printing, and they differ significantly in mechanical performance, physical properties, durability, and usage environments.
PLA is the most widely used 3D printing filament for the fused deposition modeling process.PLA filament is typically rigid filament with bright colors and has the following characteristics:
Mechanical Properties:
Rigidity and Strength: High hardness (Shore D 80-90), tensile strength usually between 50-70 MPa, suitable for bearing static loads.
Flexibility: Low, with elongation at break only 5-10%, making the material brittle and prone to fracture under impact.
Impact Resistance: Average, not suitable for high-impact applications.
Thermal Properties:
Glass Transition Temperature (Tg) around 55-65°C, low heat resistance, prone to softening and deformation above 60°C.
Physical and Chemical Properties:
Density: About 1.24-1.25 g/cm³, lightweight.
Hygroscopicity: High, easily absorbs moisture causing printing defects like bubbling; recommended to store dry.
Chemical Resistance: Moderate, resistant to weak acids and bases but not to strong solvents.
Odorless: Almost no smoke or odor during printing, suitable for indoor use.
Printing Characteristics:Easy to print with low shrinkage, minimal warping, good layer adhesion, smooth surface, and excellent detail reproduction.
PLA is the preferred material for beginners and prototyping due to its environmental friendliness, ease of use, low cost (about 1/2 to 1/3 the cost of TPU), high precision, and suitability for printing visually appealing and structurally simple models and decorative items.
However, its poor heat resistance and brittleness make it unsuitable for outdoor or functional load-bearing parts (which can be improved by annealing or adding reinforcements).
TPU filament is soft and flexible, often loosely wound on spools, comes in various colors, and usually has a translucent or matte finish.
Mechanical Properties:
Flexibility and Elasticity: Very high, with elongation at break typically 300%-800%, capable of repeated stretching and rapid recovery, similar to rubber.
Tensile Strength: Medium (20-50 MPa), but with excellent toughness and strong tear resistance.
Impact Resistance: Excellent, not prone to cracking, suitable for dynamic loads.
Hardness: Adjustable, usually Shore A 85-95 (soft like shoe soles), with some variants ranging from Shore A 60-98.
Thermal Properties:
Moderate heat resistance, can withstand 80-120°C (much higher than PLA), retaining elasticity at high temperatures, demonstrating superior temperature resistance compared to PLA.
Physical and Chemical Properties:
Density: About 1.10-1.25 g/cm³, lightweight and waterproof.
Hygroscopicity: High, absorbs moisture easily causing printing defects; requires dry storage.
Chemical Resistance: Excellent, resistant to oils, solvents, acids, bases, ozone, and ultraviolet light.
Abrasion Resistance: Extremely high, surface resists friction, suitable for wear environments.
Printing Characteristics:
Soft filament with higher printing difficulty: requires slow speeds (15-40 mm/s), direct drive extruder, prone to stringing and clogging.
Good layer adhesion, printed parts are flexible, non-slip, and comfortable to touch.
TPU is the preferred material for printing flexible parts, featuring high elasticity, impact resistance, wear resistance, and chemical resistance.
It is suitable for functional parts but has higher printing difficulty, cost (about 2-3 times that of PLA), and a slightly rougher surface, making it less suitable for high-precision static models
Property | PLA | TPU |
|---|---|---|
Flexibility | Rigid, brittle | Highly elastic (300%-600% elongation) |
Strength | Tensile strength 50-70 MPa | 20-50 MPa, better impact resistance |
Heat Resistance | Around 60°C | 80-100°C |
Printing Difficulty | Easy (beginner-friendly) | More difficult (requires slower print speeds, direct drive extruder) |
Durability | Moderate, not wear-resistant | Excellent (oil and abrasion resistant) |
Environmental Impact | Biodegradable | Non-biodegradable but durable |
Cost | Lower | Higher |
PLA Filament vs TPU Filament: 3D Printing Parameters
When it comes to 3D printing, understanding the specific parameters for PLA and TPU filaments is crucial to achieving consistent results and high print quality. Both materials require different settings due to their unique properties.
Printing Temperature
PLA filament typically prints best at temperatures ranging from 180°C to 230°C. Its low melting point and good layer adhesion make it relatively easy to print, even on printers without a heated bed.
In contrast, TPU filament requires a higher printing temperature, generally between 225°C and 250°C, to properly melt and extrude. This higher temperature helps TPU maintain its elasticity and durability in the final print.
Print Bed Temperature and Adhesion
PLA prints well on an unheated bed, but a heated bed set between 50°C and 60°C can help prevent warping and improve layer adhesion. Applying a glue stick or painter’s tape on the print bed further enhances adhesion for both PLA and TPU.
TPU filament benefits more from a heated bed, typically around 40°C to 60°C, to ensure good adhesion and reduce the risk of print failure.
Print Speed and Retraction
Due to its rigidity, PLA can be printed at relatively high speeds, often between 40 mm/s and 60 mm/s, allowing for faster production of rigid parts.
TPU, being a flexible material, requires slower print speeds, usually between 15 mm/s and 30 mm/s, to prevent extrusion issues such as stringing or clogging.
Retraction settings for TPU should be minimized to avoid filament jams, whereas PLA can handle more aggressive retraction to reduce stringing.
Extruder Type and Filament Handling
Printing TPU filament is generally easier with a direct drive extruder, which provides precise control by feeding the filament directly into the hot end. This setup prevents the flexible TPU from bending or kinking inside the filament path.
PLA, or normal PLA, is less demanding and can be printed successfully with both Bowden and direct drive extruders.
Cooling and Layer Adhesion
PLA benefits from active cooling during printing, which helps achieve a glossy finish and prevents deformation. TPU, on the other hand, requires minimal cooling to maintain layer adhesion and prevent warping.
Cooling fans should be used sparingly or turned off during TPU printing to ensure optimal mechanical properties.
Post-Processing Considerations
PLA prints generally have a smooth surface and can be easily sanded or painted, making them suitable for decorative prints and prototypes.
TPU parts, due to their flexible and abrasion-resistant nature, are more challenging to post-process but excel in applications requiring shock absorption and repeated bending.
By adjusting these printing parameters according to the filament type, users can optimize their 3D printing process to produce durable parts, flexible components, or detailed prototypes, depending on their project needs.
PLA vs TPU:Applications
PLA and TPU each have their advantages in practical applications, suitable for different scenarios and needs.
Applications of PLA:
Suitable for making prototype models, decorative items, figurines, and educational supplies that do not require withstanding significant mechanical stress.
Ideal for static parts requiring high precision and smooth surfaces, such as architectural models and display components.
Due to its ease of printing and low cost, PLA is very suitable for beginners and projects with limited budgets.
Applications of TPU:
Suitable for making phone cases, insoles, seals, shock absorbers, and various wearable devices, thanks to its excellent elasticity and wear resistance.
Ideal for functional parts that require bending, stretching, and impact absorption, such as robotic joints, protective covers, and sports equipment accessories.
Its good oil resistance and abrasion resistance make it an ideal material for industrial applications like automotive parts and tool handles.
In summary, if your project emphasizes fine appearance, easy printing, and low cost, PLA is a good choice; whereas if parts require flexibility, durability, and impact resistance, TPU is more suitable.
PLA vs TPU:Which Is Best For Your Project?
PLA and TPU are two commonly used materials in 3D printing, each with its own characteristics. The choice depends on the specific application and requirements. Below is an objective comparison across key dimensions.
Printing Difficulty and Ease of Use
PLA is easier to print, with low shrinkage and minimal warping, making it suitable for beginners. TPU requires more careful handling; although the printing temperature ranges are similar, extrusion speed and retraction settings need adjustment to avoid stringing or uneven extrusion.
TPU is especially challenging for Bowden extruders, and a direct drive extruder is recommended to improve precise control.
Mechanical Performance and Durability
TPU has clear advantages in elasticity and toughness, with Shore hardness typically between 75A and 95A. It is stretchable, wear-resistant, and impact-resistant, suitable for shock absorption or flexible parts.
PLA, on the other hand, is more rigid, with higher tensile strength but greater brittleness, prone to breaking under stress. Flexible PLA variants can bend and recover to some extent but cannot match TPU’s stretchability.
Application Suitability
PLA is suitable for scenarios requiring high precision but low load-bearing capacity, such as decorative items, prototype models, or partial structures of eco-friendly shoe uppers.
TPU is better suited for durable flexible parts like shoe uppers, shock absorbers, or mechanical joints, particularly excelling in sports equipment.
Environmental and Safety Characteristics
PLA is made from renewable resources like corn starch, with good biodegradability and non-toxic printing emissions. However, it has poor heat resistance (low glass transition temperature) and tends to become brittle with prolonged UV exposure.
TPU offers superior weather resistance, abrasion resistance, and oil resistance but has weaker environmental credentials and requires good ventilation during printing.
Cost and Processability
PLA is lower cost and can be used directly on most FDM printers without modification. TPU may require printer setting optimization (such as reduced extrusion speed), and some high-performance TPUs need specialized nozzles, which can increase the usage threshold.
Both PLA and TPU have their strengths and weaknesses, with no absolute superiority. Choose PLA if you prioritize ease of printing, environmental friendliness, and fine appearance; choose TPU if flexibility, durability, and functionality are needed.
Many users keep both filaments on hand, switching according to project needs. For multi-material printing, combining the two (e.g., PLA for the main body and TPU for flexible parts) can create more complex components.