FGF 3D Printing: The Balance for Soft TPE Applications

This are opening new opportunities in healthcare, soft robotics, automotive applications, and customized consumer products. However, while printing softer materials is now technically possible, achieving consistent structural performance remains a significant challenge. As a result, Shore hardness has emerged as one of the most important factors influencing the success of soft TPE applications.

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Why FGF Is Changing Soft Material Manufacturing

Unlike conventional Fused Deposition Modeling (FDM), which relies on filament, FGF uses raw polymer pellets that are fed directly into a screw extruder. Consequently, manufacturers eliminate the filament production step and avoid potential issues related to filament diameter tolerances, residual stresses, and feeding instability. This advantage becomes particularly important when processing soft elastomers.

Furthermore, highly flexible filaments often buckle before reaching the print nozzle, making extremely soft materials difficult to process with traditional systems. In contrast, pellet extrusion transports material using a rotating screw, which allows printers to handle significantly softer compounds without feed interruptions. Therefore, FGF has become a preferred technology for applications requiring high elasticity and customized mechanical properties.

Companies such as CEAD and Mitsubishi Chemical Group continue to expand the capabilities of pellet-based additive manufacturing, particularly in large-format industrial applications. As these systems evolve, they allow engineers to explore material combinations that were previously impossible to print reliably. 

How Soft Can TPE Really Be?

Commercially available TPE materials already reach hardness levels around 25 Shore A, and researchers continue pushing these limits even further. Recent studies have demonstrated successful printing of materials within the Shore 00-30 range, which traditionally belonged to silicone elastomers instead of thermoplastics.

To put this into perspective, a common TPU filament used in desktop 3D printing often measures around 95 Shore A. Meanwhile, a TPE with 30 Shore A exhibits a much softer, rubber-like feel. As hardness decreases, designers gain greater flexibility for creating cushioning elements, wearable products, anatomical models, and soft robotic components.

Moreover, advances in pellet-based additive manufacturing continue to expand the available material portfolio. Consequently, designers can now target applications requiring comfort, flexibility, and impact absorption without sacrificing the advantages of thermoplastic processing.

The Real Challenge: Maintaining Structural Integrity

Although softer materials offer clear functional advantages, they introduce new engineering challenges. Most importantly, part stability decreases as Shore hardness drops.

Research consistently shows that Shore hardness strongly influences mechanical performance. However, hardness alone does not determine final properties. Instead, the interaction between material hardness, infill density, flow rate, layer bonding, and print parameters ultimately defines the behavior of a finished component.

For example, when engineers reduce infill density to increase flexibility, they simultaneously reduce the structure’s ability to carry loads. Therefore, extremely soft materials often depend more on geometric design than material properties alone. As a result, engineers must carefully optimize print settings to maintain a balance between softness and stability.

Additionally, studies involving gyroid infill structures demonstrate that adjustments in flow rate and internal geometry can alter the perceived hardness of a printed part. Consequently, designers can engineer different stiffness zones within the same component without changing the material itself. This capability creates exciting possibilities for advanced functional products.

Medical and Industrial Opportunities

The healthcare sector illustrates the potential of soft-material additive manufacturing particularly well. Medical-grade TPEs already support applications such as surgical training models, orthotic devices, prosthetic interfaces, and patient-specific cushioning components.

At the same time, customized diabetic insoles demonstrate how engineers can use variable-density structures to distribute pressure more effectively across the foot. By deliberately controlling localized stiffness, manufacturers improve comfort while reducing injury risks.

Beyond healthcare, industries including automotive, soft robotics, consumer goods, and wearable technology increasingly demand flexible components with tailored mechanical properties. Therefore, FGF offers a valuable manufacturing solution that combines design freedom, material efficiency, and rapid customization. 

Looking Ahead

The future of soft-material additive manufacturing does not depend solely on developing softer polymers. Instead, success will come from understanding the relationship between process parameters, material behavior, and structural design.

As research continues, manufacturers will likely achieve even greater control over process-property relationships. Consequently, they will produce softer, lighter, and more reliable components for a growing range of applications. FGF has already overcome many of the processing limitations associated with ultra-soft elastomers. Now the industry’s focus shifts toward optimizing structural performance while preserving the unique functionality that makes soft TPE materials so valuable.

To read more: What is Fused Granulate Fabrication (FGF)?