An additively manufactured silicone polymer: Thermo-viscoelastic experimental study and computational modelling

Abstract

The additive manufacturing (AM) is a new paradigm across various disciplines of engineering sciences. Despite significant advances in the areas of hard material printings, the options for 3D printed soft materials are still limited. Most of the existing 3D printed polymers are in the areas of acrylics and polyurethanes or their composites. Recently emerged Digital Light Synthesis (DLS) technology hugely accelerates the additive manufacturing of soft polymers. A DLS-inspired 3D printer uses a continuous building technique instead of a layer-by-layer approach, where the curing process is activated by an ultra-violet (UV) light. In this contribution, a DLS-based digitally printed silicone (SIL30) is experimentally characterized. To understand polymer's temperature-dependent mechanical responses, an extensive thermo-viscoelastic experimental characterisation at various strain rates under tensile deformation and temperature fields from -20 C to 60 C is performed. The study reveals significant effects of time-and temperature-dependency on the mechanical responses of the 3D printed silicone. Motivated by the thermo-mechanical results of the polymer, a thermodynamically consistent constitutive model at large strain is devised. Afterwards, the model is calibrated to the data that results in the identification of relevant parameters. The model predicts the experimental results with a good accuracy. 3D printed soft polymers are major candidates in designing complex and intricate architectured metamaterials for biomedical applications. Hence, a comprehensive thermo-mechanical experimental study and subsequent constitutive modelling will facilitate in designing and simulating more complex cellular metamaterials using 3D printed silicones.

Additive manufacturing and the COVID-19 challenges: An in-depth study

“…The built part is supported by a structure, which holds pattern in the liquid resin bath, and prevents the newly formed layer from moving out of the position from the already built portion. Once a layer is scanned and cured, the platform or the support structure moves downward or upward by several micrometers (μm, based on the resolution of a printer) to make another layer of liquid resin available to be cured [22] , [23] , [7] , [8] , [21] .…”

“…Parts can be fabricated in a single step removing the need for assembly in some cases, thus reducing post-processing and lead times. Thanks to these attractive manufacturing advantages, AM is extensively utilised in medical, aerospace, and automotive industries [5] , [6] , [7] , [8] , to mention a few. The advantage of part customisation is utilised highly in medical applications, in which parts can be customised to the individual patient's data [9] , [10] .…”

Effects of Postcuring Temperature on the Mechanical Properties and Biocompatibility of Three-Dimensional Printed Dental Resin Material

“…There are biocompatible soft polymers such as silicone, polyurethane which can be fully cured during DLS/DLP printing process. Thus, they do not require postprocessing treatment [15]. However, postprocessing treatment such as thermal or UV-light curing is indicated for acrylic-based photosensitive resin in order to crosslink unreacted monomers and thereby complete the polymerization process after printing, which improves its final thermal and mechanical properties [16][17][18] depending on 3D printer type.…”

Optimization of Manufacturing Parameters and Tensile Specimen Geometry for Fused Deposition Modeling (FDM) 3D-Printed PETG

“…Build orientation, layer thickness, and feed rate are discussed on 3D-printed PLA samples in [48], and layer thickness and raster angle parameters for PLA and ABS in [49]. In order to model the mechanical response of additive manufactured polymers [50][51][52], well-known homogenization techniques are used in composite materials [53], for example by using a variation of carbon-fiber content in thermoplastic matrix-based composites built by the FDM [54] and also for identifying substructure-related anisotropic properties [55] to be used in computations [56,57].…”