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In the past decade, a lot of work has been reported on the use of polyvinylidene fluoride (PVDF) based thermoplastic composites as energy storage devices, and implant materials. But hitherto little has been reported on the dimensional stability and surface characteristics of 3D-printed PVDF composites after autoclaving for implant applications. In this study, the effect of autoclaving on surface characteristics (Shore-D hardness, surface roughness (Ra), morphological characteristics), and dimensional stability of 3D printed PVDF-hydroxyapatite (HAp)- chitosan (CS) composite has been reported for implant applications. The signal-to-noise (S/N) ratio approach was used to ascertain the best setting of process parameters for 3D printing by fused filament fabrication (FFF) process. This study suggests that the best setting for the FFF process, for the 3D printing of PVDF composite (90%PVDF-8%HAp-2%CS) are the nozzle temperature (NT) of 225°C, raster angle (RA) 0°, and printing speed (PS) 40 mm/s, resulting in Shore-D hardness 48.5 HD (before autoclaving) and 55.0 HD (after autoclaving), dimensional deviation 0.01 mm (after autoclaving). The results are supported by scanning electron microscopy (SEM) and Fourier transmission infrared (FTIR) spectroscopy analysis. [ABSTRACT FROM AUTHOR]

In the recent past some studies have been reported on the compressive, tensile, and flexural properties of 3D-printed polyvinylidene fluoride (PVDF) composite-based intramedullary (IM) pins for canines. However, in actual working conditions (due to trauma or accident), the IM pin may also be under torsional loading conditions. But hitherto little has been testified on the torsional behavior of PVDF composite-based IM pins. This study highlights the torsional behavior at 1 rpm (from 0 to 800° of the angle of twist/rotation) of PVDF composite (PVDF-90%; hydroxyapatite (HAp8%); chitosan (CS2%)) based IM pin fabricated by fused filament fabrication (FFF) process. The study suggests that better torsional properties were obtained for 3D printed samples prepared at nozzle temperature (NT) of 235°C, raster angle (RA) of 45°, and printing speed (PS) of 60 mm/s respectively resulting in a maximum torque of 3.44 Nm at the angle of twist of 800° (as per ASTM A938). The morphological analysis based on scanning electron microscopy (SEM) supports the results of the fractured surface (at cross section) and along the lateral axis. [ABSTRACT FROM AUTHOR]

In the last two decades, several studies have been conducted for the process parametric optimization of fused filament fabrication (FFF) with a variety of thermoplastic composites, especially for mechanical properties. But hitherto less has been conveyed, on the development of dynamic reduced order models (ROMs) for digital twining (DT) of tensile properties (of 3D printed implants/scaffolds) with novel thermoplastic-based composites. In this study, for the generation of dynamic ROM (for hybrid analytics), the signal-to-noise (S/N) ratio was used to ascertain the best settings of parameters for tensile properties of polyvinylidene fluoride (PVDF) composite. The study suggests that the best setting of the FFF process, for the 3D printing of PVDF composite (90% PVDF, 8% hydroxyapatite (HAp), and 2% Chitosan (CS) (for maximizing the tensile properties as per ASTM-D638-Type-V) are nozzle temperature (NT) of 235°C, raster angle (RA) 45°, printing speed (PS) of 60 mm/s respectively resulting in peak load (PL) 394.87 N, peak stress (PSt) 33.92 MPa, Young's modulus (E) 2.606 MPa. For a modulus of toughness (MOT) of 0.484 MPa, the best settings are NT 230°C, RA 90°, and PS 50 mm/s. The results are supported by the morphological analysis. [ABSTRACT FROM AUTHOR]