This study explores the shape-morphing behavior of 4D-printed structures made from Polylactic Acid (PLA), a prominent bio-sourced shape-memory polymer. Focusing on the response of these structures to thermal stimuli, this research investigates how various printing parameters influence their morphing capabilities. The experimental approach integrates design and slicing, printing using fused deposition modeling (FDM), and a post-printing activation phase in a controlled laboratory environment. This process aims to replicate the external stimuli that induce shape morphing, highlighting the dynamic potential of 4D printing. Utilizing Taguchi’s Design of Experiments (DoE), this study examines the effects of printing speed, layer height, layer width, nozzle temperature, bed temperature, and activation temperature on the morphing behavior. The analysis includes precise measurements of deformation parameters, providing a comprehensive understanding of the morphing process. Regression models demonstrate strong correlations with observed data, suggesting their effectiveness in predicting responses based on control parameters. Additionally, finite element analysis (FEA) modeling successfully predicts the performance of these structures, validating its application as a design tool in 4D printing. This research contributes to the understanding of 4D printing dynamics and offers insights for optimizing printing processes to harness the full potential of shape-morphing materials. It sets a foundation for future research, particularly in exploring the relationship between printing parameters and the functional capabilities of 4D-printed structures.
This study aims to provide an in-depth characterization of the intelligent behaviour exhibited by structures fabricated using fused deposition modelling (FDM) printing technology. The primary objective is to understand the variability in the shape-morphing behaviour of additively manufactured PLA structures. A comprehensive analysis is conducted to shed light on the impact of various factors on shape transformation, encompassing both working and printing parameters. To establish the relationship between the printing and working parameters with the shape morphing characteristics, the experimental procedure employs Taguchi's method design of experiments. Notably, the study quantitatively reveals the extent of these parameters' impact on the characteristics.
Currently, many novel innovative materials and manufacturing methods are developed in order to help businesses for improving their performance, developing new products, and also implement more sustainability into their current processes. For this purpose, additive manufacturing (AM) technology has been very successful in the fabrication of complex shape products, that cannot be manufactured by conventional approaches, and also using novel high-performance materials with more sustainable aspects. The application of bioplastics and biopolymers is growing fast in the 3D printing industry. Since they are good alternatives to petrochemical products that have negative impacts on environments, therefore, many research studies have been exploring and developing new biopolymers and 3D printing techniques for the fabrication of fully biobased products. In particular, 3D printing of smart biopolymers has attracted much attention due to the specific functionalities of the fabricated products. They have a unique ability to recover their original shape from a significant plastic deformation when a particular stimulus, like temperature, is applied. Therefore, the application of smart biopolymers in the 3D printing process gives an additional dimension (time) to this technology, called four-dimensional (4D) printing, and it highlights the promise for further development of 4D printing in the design and fabrication of smart structures and products. This performance in combination with specific complex designs, such as sandwich structures, allows the production of for example impact-resistant, stress-absorber panels, lightweight products for sporting goods, automotive, or many other applications. In this study, an experimental approach will be applied to fabricate a suitable biopolymer with a shape memory behavior and also investigate the impact of design and operational parameters on the functionality of 4D printed sandwich structures, especially, stress absorption rate and shape recovery behavior.
Nowadays, there is particular attention towards the recycling of waste materials which is a critical issue for environmental protection and waste management. Polymer materials have numerous applications in daily life products. As a result, plastic pollution has become one of the biggest threats to nature, therefore recycling or replacing them with bio-based materials can significantly help the ecosystems. So far, many studies have investigated the possibility of reusing plastic waste, as a second life, to obtain consumable products. The 3D printing market is one of the great sectors that can utilize a wide range of thermoplastic polymers. This technology provides a unique capability to produce complex shape structures and products that cannot be produced by other manufacturing processes. In particular, Fused Filament Fabrication (FFF) is a common printing technology that consumes thermoplastic filaments including recycled materials. This printing technique has been also very successful in using novel high-performance materials with sustainable aspects. The reSHAPE project aims to develop novel smart filaments, with shape memory properties, from recycled materials. The filaments can be applied for the design and fabrication of smart products with dynamic behavior. In particular, the fabricated parts can shift from a plastic-deformed shape into a recovered original shape when being triggered by an external stimulus, like temperature. For that, we will specifically apply recycled polylactic acid (PLA) and thermoplastic polyurethane (TPU) as the main materials in this study. Because they both have proper shape memory properties and also TPU can potentially enhance the material flexibility which is required in the design and fabrication of functional components. As a result, this study will obtain a proper combination of these materials with good printability and functionality that can be used for a wide range of products from the aerospace and automotive sectors to soft robotics and medical devices.
