Estado da arte da impressão 4D: conceitualização e perspectivas tecnológicas

Abstract

The present work aimed to draw an overview of the main points related to the state of the art of 4D Printing through the analysis of different literature available on the subject. The origins of the additive manufacturing process were studied, with a brief exposition of its history and a survey of the names of its developers, along with their contributions. Within the history, some fundamental concepts of 3D Printing and, later, of 4D Printing were seen. In the literature review, the fundamental points that permeate the 4D Printing technology were seen, initially with exposition of a series of general concepts that help in the definition of this type of process and with the survey of the main pillars that make 4D Printing an advanced processing in the engineering area, namely: 3D Printing facility, stimulus, stimulus-responsive material, interaction mechanism and mathematical modeling. Following the literature review, what are smart materials were defined, more specifically materials with shape memory, and the differentiation of the concept of Shape Memory Materials and Shape Changing Materials. Subsequently, there was a survey of the materials most commonly used in the process: Shape Memory Polymers (SMP), Shape Memory Alloys (SMA) and hydrogels, and the reason for their feasibility of use, through the analysis of characteristics of their responsive behavior to different stimuli. Subsequently, the main behaviors of response to stimuli of 4D Printing products were seen, which are the behaviors of folding, bending, swelling and stretching. Also, the basic types of stimuli were defined: thermal and with application of force, thermal and without application of force, pH and without application of force and thermo-photo-mechanical and their functioning was explained, in addition to the scoring of possible other mechanisms. Further on, there was a survey of the main printing techniques used in additive manufacturing together with their definitions and process steps, being Stereolithography (SLA), Fused Deposition Modeling (FDM), Direct Ink Writing (DIW) and Digital Light Projection (DLP) the most popular techniques. Finally, the main applications were researched, mostly present in the health, robotics and aerospace areas due to the high possibility of customization of the products of the process and also the perspectives of new applications, which would have a great impact on everyday life.