FUTURE OF 4D PRINTING IN SOFT ROBOTICS AND INTELLIGENT AUTOMATION
Achin Srivastav1, Nidhi Srivastav2
1Department of Mechanical Engineering, 2Department of Computer Science & Engineering,
Swami Keshwanand Institute of Technology, Management & Gramothan, Jaipur, India
Abstract: Four-dimensional (4D) printing has emerged as a transformative manufacturing paradigm that integrates time as a fourth dimension into three-dimensionally printed structures, enabling programmable shape transformation, autonomous actuation, and adaptive functionality in response to environmental stimuli. This comprehensive review synthesises advances in 4D printing technologies, smart materials, actuation mechanisms, and their convergence with soft robotics and intelligent automation systems over the period 2015–2025. We critically examine stimulus-responsive materials including shape-memory polymers (SMPs), hydrogels, liquid crystal elastomers (LCEs), magneto-active composites, and multi-material systems, comparing their actuation performance, biocompatibility, and scalability across 37 quantitative metrics derived from over 350 peer-reviewed publications. Key application domains surveyed include minimally invasive surgical devices, adaptive soft grippers, wearable exoskeletons, underwater autonomous vehicles, and micro-scale drug delivery systems. We further assess the integration of machine learning, computational design, and bio-inspired principles with 4D printing to achieve closed-loop intelligent soft robotic systems. Despite remarkable progress, persistent challenges in material fatigue, multi-stimulus control, scalable manufacturing, and regulatory compliance continue to impede clinical and industrial translation. This review concludes with a forward-looking roadmap identifying high-priority research directions and projected technology readiness levels through 2030.
Keywords: 4D printing; soft robotics; shape-memory polymers; intelligent automation; stimulus-responsive materials; smart actuators; bio-inspired design; additive manufacturing
VOLUME 10 ISSUE 04 2026: 20 – 31