TPU filament is one of the most versatile flexible materials for FDM and FFF 3D printing. From very soft 70A grades to firm Shore D materials, different TPU hardness levels can be selected for cushioning, footwear, seals, grips, protective parts and engineering components.
What Is TPU Filament?
TPU stands for Thermoplastic Polyurethane. It is a thermoplastic elastomer that combines rubber-like flexibility with the processing advantages of thermoplastic materials.
Unlike rigid materials such as PLA or PETG, TPU can bend, compress and recover from deformation. Depending on the formulation and hardness, TPU printed parts can range from very soft and flexible to relatively firm engineering components.
Key Properties of TPU Filament
Flexibility
TPU can bend and deform under load while recovering toward its original shape after the force is removed.
Toughness
Suitable for parts exposed to repeated handling, compression, bending and mechanical stress.
Wear Resistance
Many TPU formulations provide useful resistance to abrasion and repeated surface contact.
Shock Absorption
Flexible structures can absorb impact and vibration, making TPU useful for protective and cushioning components.
What Does TPU Hardness Mean?
TPU filament is commonly classified according to Shore hardness. Softer materials are generally measured on the Shore A scale, while harder TPU grades can extend into the Shore D range.
TPU Hardness Comparison
| Hardness | General Feel | Typical Applications |
|---|---|---|
| TPU 70A | Very soft and highly flexible | Cushioning, wearables, highly flexible parts |
| TPU 75A | Soft and flexible | Footwear, flexible accessories, protective parts |
| TPU 85A | Flexible with more support | Grips, seals, flexible housings |
| TPU 90A | Medium-soft | Protective and functional flexible components |
| TPU 95A | Firm but still flexible | General-purpose flexible parts, seals and grips |
| TPU 98A | Relatively firm | Functional parts requiring greater support |
| TPU 64D | Hard engineering TPU | Mechanical and structural flexible components |
| TPU 75D | Very firm TPU | Rigid-flex and demanding functional parts |
TPU 95A is one of the most widely used hardness levels in desktop FDM printing because it provides a practical balance between flexibility, durability and filament feeding stability.
It is flexible enough for seals, grips and protective components while remaining firm enough to print on a wide range of compatible extrusion systems.
Soft TPU vs Hard TPU
High Flexibility
Lower-hardness TPU such as 70A and 75A is designed for components that require significant bending, compression or softness.
- Cushioning structures
- Footwear components
- Wearable parts
- Soft-touch products
Greater Structural Support
Higher-hardness TPU provides more resistance to deformation while retaining greater toughness and elasticity than many rigid plastics.
- Mechanical parts
- Protective components
- Rigid-flex structures
- Industrial applications
Is TPU Difficult to Print?
TPU printing difficulty depends strongly on hardness. Firmer materials such as TPU 95A are generally easier to feed, while very soft materials can compress or buckle inside the filament path.
A short and well-constrained filament path is particularly useful when printing softer TPU grades. Direct-drive extrusion systems are therefore often preferred for highly flexible materials.
Direct Drive vs Bowden for TPU
Direct-drive systems position the extruder close to the hot end, reducing the distance in which soft filament can compress or buckle.
Bowden systems can still process firmer TPU grades successfully, but softer materials usually require more careful feeding and printing settings.
Does TPU Need to Be Dried?
TPU can absorb moisture during storage and use. Excess moisture may contribute to unstable extrusion, surface defects and inconsistent printing.
TPU should therefore be stored in sealed packaging or a dry environment. Drying may be necessary depending on the condition of the filament.
Does Infill Affect TPU Flexibility?
Yes. TPU hardness is only one factor determining how flexible the finished printed part feels.
Thicker walls generally create a firmer part.
Higher infill can significantly reduce overall flexibility.
Structural design can change how the part bends and compresses.
Common TPU Applications
Specialty TPU Filaments
Matte TPU
Flexible performance with a softer, low-gloss surface for wearables and appearance-focused products.
SILK TPU
Combines flexibility with a glossy decorative finish for accessories and creative products.
Glow-in-the-Dark TPU
Flexible filament with luminous visual effects for safety, decorative and customized applications.
Foaming TPU
Designed for lighter and softer structures such as cushioning components and footwear applications.
High-Elasticity TPU
Developed for rebound, repeated deformation and applications such as sports products and vibration-damping parts.
How to Choose the Right TPU
- High flexibility
- Cushioning
- Soft-touch components
- Wearable products
- Large elastic deformation
- General flexible parts
- Protective covers
- Grips
- Seals
- Balanced flexibility
- Structural support
- Limited deformation
- Mechanical components
- Rigid-flex designs
- Industrial parts
TPU vs PLA and PETG
TPU serves a different purpose from rigid materials such as PLA and PETG. PLA is primarily used for rigid prototypes and decorative parts, while PETG provides toughness for functional rigid components.
TPU is the more suitable choice when a part needs to bend, compress, absorb impact or repeatedly deform during use.
Choosing TPU Is About More Than Hardness
From very soft 70A and 75A materials to versatile TPU 95A and harder Shore D grades, TPU provides a broad range of flexibility for functional 3D printing.
Material hardness should be considered together with wall thickness, infill, geometry, printing equipment and the mechanical requirements of the final application.
Tecsonar provides multiple TPU hardness levels and specialty TPU filament solutions for distributors, manufacturers and professional 3D printing applications, including bulk supply, customized packaging and project-based requirements.