The Guide to 3D Printing TPU
Thermoplastic Polyurethane (TPU) is a versatile and valuable material for producing flexible, durable parts.
Research and experimentation in polyurethane chemistry led to the development of TPU, enhancing its properties and applications across various industries.
This guide aims to provide engineers and designers with an in-depth understanding of TPU and how to successfully use it in 3D printing projects.
What is TPU?
TPU is a flexible elastomer that falls between rubber and plastic in terms of its properties.
It is a block copolymer composed of hard and soft segments, which give it a unique combination of flexibility and toughness. The hard segments provide strength and structural integrity, while the soft segments contribute to its flexibility and elasticity.
Due to its durability and elasticity, TPU material has wide-ranging applications across various industries, including automotive, aerospace, and medical devices.
It is also advantageous for 3D printing, enabling the creation of customizable parts, rapid prototyping, and improving production efficiency while addressing design complexities.
This material is commonly used with the Multi Jet Fusion manufacturing method. MJF uses fine powder and fusing agents to create parts with excellent detail and strength. It’s particularly suitable for producing TPU parts that require fine detail, good surface finish, and consistent mechanical properties.
| Property | Unit | Value | Norm |
|---|---|---|---|
| THERMAL PROPERTIES | |||
| Vicat Softening Temperature | °C | 84-96 | ISO 306 |
| MECHANICAL PROPERTIES | |||
| Tensile Strength | MPa | 7-9 | DIN 53504 |
| Tensile Modulus | MPa | 75-85 | ISO 527 |
| Charpy-Notched Impact Strength | kJ/m² | No break | ISO 179-1 |
| Flexural Modulus | MPa | 75 | ISO 178 |
| Shore – Hardness | A | 88-90 | ISO 7619-1 |
| Elongation at Break | % | 150-280 | DIN 53504 |
| PHYSICAL PROPERTIES | |||
| Density | g/cm³ | 1.10 | – |
| TOLERANCES | |||
| Achievable Part Accuracy | +/- 1.5 mm for parts up to 100 mm, +/- 2% for parts beyond 100 mm | ||
| Min. Wall Thickness | mm | 1.0 | – |
TPU Properties and Characteristics
Thermoplastic polyurethane (TPU) is a versatile material that combines the benefits of both plastics and rubbers. It offers a unique set of properties and characteristics that make it suitable for a wide range of applications. Some of the key properties and characteristics of TPU include:
High Durability and Flexibility: TPU is renowned for its ability to withstand harsh environments and maintain its shape and structural integrity over time. This makes it an ideal choice for applications that require a durable material.
Chemical Resistance: TPU exhibits excellent resistance to a wide range of chemicals, including oils, greases, and solvents. This property makes it suitable for use in environments where exposure to chemicals is common.
Abrasion Resistance: TPU is highly resistant to abrasion and wear, making it perfect for applications where friction and wear are a concern, such as conveyor belts and shoe soles.
High Tensile Strength: With its high tensile strength, TPU is suitable for applications that require strong and durable materials. This property is particularly valuable in the automotive industry for components that need to withstand significant stress.
Elasticity: TPU is a flexible material that can be stretched and deformed without losing its shape or structural integrity. This elasticity makes it ideal for products that require flexibility, such as protective phone cases and flexible joints in robotics.
Resistance to UV Radiation: TPU’s resistance to UV radiation makes it suitable for outdoor applications, ensuring that the material does not degrade when exposed to sunlight.
High Durability: Overall, TPU is a durable material that can withstand harsh environments and maintain its shape and structure over time, making it a reliable choice for various industrial and consumer applications.
Chemical Composition
TPU is a type of block copolymer consisting of alternating sequences of hard segments (isocyanates) and soft segments (reacted polyol). The formulation of TPU can be adjusted to include varying amounts of these hard and soft segments.
Materials with a higher proportion of hard segments tend to be firmer and more rigid, while those with more soft segments are more elastic and flexible. This unique combination of hard and soft segments gives TPU distinctive properties, including strength, thermal resistance, flexibility, and resilience.
The ability to tailor the chemical composition of TPU makes it a highly adaptable material for diverse applications.
Physical Properties
The physical properties of TPU are primarily determined by the ratio of hard and soft segments in its composition. One of the most critical characteristics of TPU is its hardness, measured on the Shore hardness scale, which indicates its resistance to indentation.
TPU also boasts impressive tensile strength, elongation at break, and abrasion resistance, making it an ideal material for applications that demand durability and flexibility. These properties ensure that TPU can perform reliably in various environments, from the soles of shoes to the intricate components of wearable technology.
Types of TPU for 3D Printing
Several types of TPU are suitable for 3D printing, each with its unique properties and characteristics:
Polyester-Based TPU: Known for its high durability and resistance to abrasion and wear, polyester-based TPU is ideal for applications that require a tough and long-lasting material. It is commonly used in automotive parts and industrial applications where durability is paramount.
Polyether-Based TPU: This type of TPU is celebrated for its high flexibility and resistance to chemicals and solvents. Polyether-based TPU is perfect for applications that require a flexible material that can withstand exposure to harsh chemicals, such as tubing and seals.
Polyurethane-Based TPU: With its high tensile strength and resistance to abrasion and wear, polyurethane-based TPU is suitable for applications that demand strong and durable materials. It is often used in protective gear and footwear, where both strength and flexibility are required.
Hybrid TPU: Combining the benefits of different types of TPU, hybrid TPU offers a unique set of properties and characteristics. This type of TPU can be tailored to meet specific requirements, making it a versatile material for a wide range of applications.
Common TPU Applications with Abrasion Resistance
TPU is widely used across various industries, including automotive, consumer electronics, medical devices, and footwear.
Common applications include phone cases, seals, gaskets, shoe soles, and flexible joints in robotics. Its versatility makes it a popular choice for durable and flexible parts. Additionally, TPU is extensively used in consumer products such as athletic shoes and protective phone cases due to its durability and flexibility.
Some of the reasons it’s so popular include:
- Flexibility and elasticity
- High wear and abrasion resistance:
- Chemical resistance
- Good load-bearing capacity and impact strength
Troubleshooting Common TPU Printing Issues
TPU can be a challenging material to print with, and several common issues can arise during the printing process. Here are some of the most frequent problems and their solutions:
Warping: TPU can warp or deform during the printing process, especially if the print bed is not properly calibrated. To prevent warping, ensure that the print bed is level and heated to the appropriate temperature. Using a heated bed and applying an adhesive can also help keep the print in place.
Delamination: TPU can delaminate or separate from the print bed during the printing process, particularly if the print bed is not properly prepared. To avoid delamination, make sure the print bed is clean and use a suitable adhesive or build surface to enhance adhesion.
Stringing: TPU can string or ooze during the printing process, especially if the print head is not properly calibrated. To reduce stringing, adjust the retraction settings and print speed. Lowering the print temperature can also help minimize oozing.
Clogging: TPU can clog the print head or nozzle during the printing process, particularly if the print head is not properly maintained. To prevent clogging, regularly clean the nozzle and use high-quality TPU filament. Ensuring that the filament is dry and free from contaminants can also help maintain a smooth printing process.
By properly calibrating the print bed and print head, maintaining a controlled print environment, and using high-quality TPU filament, you can minimize the risk of these common printing issues and achieve successful 3D prints with TPU.
Post-Processing Techniques for TPU
Surface finishing: Techniques such as sanding, polishing, and tumbling can help achieve the desired surface smoothness. These processes are essential for improving aerodynamics and reducing friction in parts like drone bodies or automotive components.
Painting and coating: Applying protective and aesthetic coatings enhances the durability and appearance of 3D-printed TPU parts. Coatings can also provide additional chemical resistance and UV protection, making them suitable for outdoor applications.
Heat treatment: Annealing and other heat treatments can improve the mechanical properties of TPU parts, such as increasing their strength and flexibility. Controlled heating can also reduce internal stresses and improve dimensional stability.
Machining and trimming: For applications requiring precise tolerances, additional machining and trimming may be necessary. This ensures that parts fit together correctly and meet specific design requirements.
Start Your Project with MakerVerse
3D printing with TPU offers designers and engineers unparalleled flexibility and customization possibilities. From rapid prototyping to full-scale production, TPU’s unique properties make it an ideal material for a wide range of applications.
MakerVerse provides a comprehensive range of technologies and materials, including TPU, to support every stage of your manufacturing process.
Whether you need a single prototype or a large production run, MakerVerse offers the tools and expertise to bring your designs to life with industrial-grade quality and precision.
