Manufacturing Complex Airtight Soft Pneumatic Actuators for Soft Robotics: Process Evaluation and Optimization
DOI:
https://doi.org/10.12974/2311-8717.2026.14.09Keywords:
Soft pneumatic actuators, Soft robotics, Additive manufacturing, Fused deposition modeling (FDM), Digital light processing (DLP), Silicone casting, AirtightnessAbstract
Manufacturing remains a major challenge in the development of complex soft pneumatic actuators, where geometric fidelity must be achieved without compromising compliance, structural integrity, or airtightness. This study introduces a systematic manufacturing framework in which a single complex actuator architecture is used as a common benchmark to evaluate heat-shrink forming, silicone casting, powder- and liquid-based additive manufacturing, and fused deposition modeling (FDM). The processes were assessed using the same criteria: geometric fidelity, flexibility, structural integrity, airtightness, manufacturing complexity, and post-processing requirements. A key contribution of the study is the use of observed failure mechanisms to distinguish inherent process limitations from defects that can be corrected through process development, providing a direct basis for manufacturing process selection. Heat-shrink forming, casting, powder-based processes, and the investigated digital light processing (DLP) route were limited primarily by geometric conformity, bonded interfaces, inaccessible residual material, and material and post-processing constraints, respectively. FDM was retained because its dominant defects could be progressively reduced without simplifying the actuator architecture. The results further showed that pneumatic sealing depends strongly on extrusion-path architecture rather than wall thickness alone, while support-free geometry is important for enclosed pneumatic structures. These findings provide practical manufacturing guidance for the design and fabrication of complex, flexible, and airtight soft pneumatic actuators.
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