Stretching the Limits: Advances to 3D Print Flexible Components

The ability to 3D print exceptionally elastic and flexible components opens doors across soft robotics, wearables, prosthetics, and medical devices. Engineers made impressive progress in materials and printing techniques to achieve high flexibility in printed objects.

But what key innovations now enable next-generation stretchable 3D printed structures?

Here we explore some of the most impactful advancements in flexible 3D printing processes and printed material options.

1. Novel Elastic Print Materials

Newly engineered polymers and composites provide tunable elastic properties exceeding traditional 3D printing materials. These expand the design space for flexible printed components.

Thermoplastic Polyurethanes (TPUs)

Fine-tuned TPUs deliver shore hardness variability from rigid to rubber-like with exceptional printed elongation percentages. TPUs also offer good abrasion and tear resistance.

Liquid Silicone Rubbers

RTV (room temperature vulcanized) silicone resins offer very high tear strength when cured during stereolithography 3D printing processes. The resulting printed silicones provide exceptional recovery from repeated compressive strains.

Graphene Enhanced Composites

Careful dispersion of graphene flakes into TPU filaments enhances tensile strength and flexibility compared to unfilled TPU. Printed composites approach 150% strain at failure.

Shape Memory Polymers

Stimuli-responsive shape memory polymers leveraging material jetting retain high elasticity and ability to reshape when exposed to heat or moisture after printing.

2. Advanced Printing Techniques

Innovators also developed new printing processes and add-ons boosting printed part elasticity during and immediately after printing.

Microlattice Structures

Microlattice infills with carefully designed cell dimensions minimize overall part stiffness while still providing excellent structural recovery from compressive strains exceeding 50%.

In-Process Strain Annealing

Heated rollers precisely apply strain to printed layers, aligning polymer chains to enhance elasticity. Parts show over 300% improvement in maximum elongation when using this technique.

Fiber Reinforced Extrusion

Short fiber mixing and deposition achieves strength and flexibility in large printed components approaching that of injection molded plastics. Anisotropic fiber alignment controls directional flexibility.

Direct Ink Writing

Careful ink rheology control enables printing extremely flexible complex hierarchical structures with micro-scale filamentary features.

3. Integrated Post-Processing

Secondary processing after printing also further boosts final part flexibility.

Infiltration

Infusing micro-porous printed parts with low viscosity polymers or resins improves interlayer adhesion and matrix connectivity leading to substantial flexibility improvements.

Ozone Treatment

Controlled ozone exposure increases printed surface energy, aiding subsequent polymer infusion into printed composites to enhance flexibility.

Thermal Annealing

Strategic heating and cooling after printing allows precise tuning of cross-link density and maximization of polymer chain mobility directly tailoring elasticity.

With advanced materials and printing processes, 3D printing is stretching previous limits and expanding possibilities for flexible printed structures. From microlattice prosthetics to haptic soft sensors, printed elasticity innovations bring within reach applications not before possible.