Accessing Thermal and Mechanical Performance of 3D-Printed Polymer Structures created with Fused Filament Fabrication

Abstract

This study primarily focuses on assessing thermal and mechanical performance of 3D printed polymer honeycomb structures from Hyper PLA material through fused filament fabrication method. Two types of own digital models were designed with SolidWorks software. These two geometries were considered into two directions, perpendicular and longitudinal directions to the honeycomb patterns. They were named as Design 1 horizontal, Design 2 vertical, Design 2 horizontal and Design 2 vertical. The test specimens for heat transfer tests and mechanical tests (tensile and flexural) were designed separately. The dimensions of the specimen for heat transfer were 39.25*39.25*32 mm3. According to the standard codes, ISO 527 and ISO 179, test specimens for tensile test and flexural test were designed. Then all test specimens were printed through fused filament fabrication method. The slicing parameters were 100% infill density, 200 mm/min speed, 0.2 mm layer thickness, and rectilinear infill pattern. The printing parameters were 220 °C, bed temperature 53°C and temperature and surrounding temperature 34 °C. The speed of cooling fan was 0-30% initially up to 1-3 layers and after that 100%. Steady-state heat conduction tests were carried out for these four geometries with the known heat source (62.1 V and 0.13 A) for 32mm thick side. The temperatures at heated surface (T1) and cold surface (T2) were around 326.25 K to 298.55K which was used to calculate the thermal conductivity. The results were laid between 6.211 to 7.657 W/K.m for all cases. A computational modelling with COMSOL was carried out to ensure the result obtained from steady-state heat conduction test. COMSOL gave the almost same values of the experiment in horizontal direction. Test specimens in all four configurations for tensile and flexural testing were carried out by universal testing machine under test codes the code ISO 527 and ISO 178 respectively. It revealed that the highest young modulus (1639.80 MPa), yield strength (13.99 MPa) and flexural modulus (2155.38 MPa) are laid with Design 1 Horizontal sample while maximum ultimate tensile strength (32.336 MPa) and flexural strength (65.198 MPa) are Design 2 Horizontal sample.