Creating a 4D printing toolkit by comparing the printing parameters of print patterns and infill density

Abstract

Four-dimensional printing (4DP) has shown a rapid advancement in AM. 4DP is described by the formula of 3D printing + time. It is an active and dynamic printing system in which shape, structure, colour, etc., can spontaneously deform according to the appropriate environment, materials, and time sequence (Pugliese et al., 2022). These 4DP is a new technology that needs to be developed. Since most scholars’ research is focused on scientific theories and more technical aspects, research on print control and the usefulness of extracting effective print is very limited and fragmented. This study identifies the optimal ways in which to control the printing parameters of the material extrusion to ensure the widespread use of 4DP. It establishes a design guideline for 4DP by providing a basis for achieving user-intended shape deformation and restoration or more complex shape deformation. This study aims to achieve the most predictable and accurate shape deformation and restoration, which is achieved by identifying the types and characteristics of the various backgrounds and knowledge related to 4DP as well as the shape-changing behaviours and printing parameters that can be implemented in 4DP through conducting a literature review. Furthermore, various Shape Memory Effects (SMEs) are discovered such as shape recovery time and shape recovery quality through water bath experiments. In addition, based on the numerical data derived for SMEs, this research also proposes a toolkit for controlling systematic 4DP SMEs. This study investigates how polylactic acid, a shape memory polymer, can be programmed by manipulating its parameters in the slicing step. For this purpose, a water bath experiment is used to show the influence of the printing pattern, infill density, and recovery temperature on printed parts’ bending shape recovery quality and the shape recovery rates. The printing parameter experiment proves that the shape recovery quality and shape recovery time can be controlled by the material’s characteristics and the printing parameters. The printing parameter control method proposed in this thesis can guide the design and application intended by researchers and designers through easy accessibility and usability. In addition, 4DP-related theoretical knowledge, tools, methods and results presented in this research can be utilized to generate new research results or to develop new applications and suggest guidelines for the proper use of 4DP, saving time and money. This discovery allows researchers, designers, and engineers to develop their work using optimal printing parameters with minimal trial and error and expand it to new applications. It can also serve as a cornerstone for the application of these results to many Additive Manufacturing technologies and industries.