scholarly journals Material modelling of FDM printed PLA part

2021 ◽  
pp. 153-160
Author(s):  
Oleg Volgin ◽  
Igor Shishkovsky
Keyword(s):  
Strain Softening ◽  
Image Correlation ◽  
Fused Deposition Modelling ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Material Response ◽  
Fused Deposition ◽  
Validation Experiment ◽  
Uniaxial Testing ◽  
Subsequent Failure

This paper focuses on modelling inelasticity of additively manufactured polylactide (PLA) thermoplastic using Fused Deposition Modelling (FDM) printing technology. The material response of PLA is viscoplastic and temperature-dependent, as is typically seen for thermoplastics. The inelastic deformation of printed PLA undergoes initial yielding, strain softening, and subsequent failure. The Three-Network (TN) constitutive model was employed in this work, which captures experimentally observed material response and consists of three molecular equilibrium and time-dependent viscous networks that act in parallel. The parameter identification was performed in accordance with experimental data from uniaxial testing and a validation experiment was carried out by loading plate with a hole and measuring its strain distribution using Digital Image Correlation (DIC) method, which was compared with the predictions from Finite Element Analysis (FEA).

Performance of Low-Cost 3D Printer in Medical Application

2021 ◽  
Author(s):  
Nor Aiman Sukindar ◽  
Azib Azhari Awang Dahan ◽  
Sharifah Imihezri Syed Shaharuddin ◽  
Nor Farah Huda Abd Halim
Keyword(s):  
Low Cost ◽  
Medical Application ◽  
Fused Deposition Modelling ◽  
3D Printer ◽  
Layer By Layer ◽  
Total Deformation ◽  
Element Analysis ◽  
Porosity Level ◽  
Fused Deposition ◽  
Printing Parameters

Abstract Fused Deposition Modelling (FDM) is an additive manufacturing (AM) process that produces a physical object directly from a CAD design using layer-by-layer deposition of the filament material that is extruded via a nozzle. In industry, FDM has become one of the most used AM processes for the production of low batch quantity and functional prototypes, due to its safety, efficiency, reliability, low cost, and ability to process manufacturing-grade engineering thermoplastic. Recently, the market is flooded with the availability of low-cost printers produced by numerous companies. This research aims to investigate the effect of different porosity levels on a scaffold structure produced using a low-cost 3D printer. Comparisons of these porous structures were made in terms of Von-Mises strain, total deformation, as well as compressive stress. Various porosity levels were created by varying printing parameters, including layer height, infill density, and shell thickness by slicing the initial solid CAD file using Repetier Host 3D printing software. Finite Element Analysis (FEA) simulation was then performed on the created scaffold structures by using Ansys Workbench 19.2. The simulation result indicates that the greater porosity level will result in higher total deformation of the structure. Meanwhile, the compression test shows that the minimum strength value obtained was favourable at 22 MPa and had exceeded that of the trabecular femur (15 MPa). However, its porosity level (maximum at 52%) was still below that of the minimum threshold of porosity level of 70 percent. However, the printing parameters currently used can be adjusted in the future. Therefore, it was deduced that the low-cost 3D printer offers promising potential to fabricate different porosity structures with multiple outcomes.

scholarly journals Additive Manufacturing Applications on Flexible Actuators for Active Orthoses and Medical Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Michele Gabrio Antonelli ◽  
Pierluigi Beomonte Zobel ◽  
Francesco Durante ◽  
Terenziano Raparelli
Keyword(s):  
Additive Manufacturing ◽  
Acrylonitrile Butadiene Styrene ◽  
Variable Stiffness ◽  
Fused Deposition Modelling ◽  
Research Projects ◽  
Element Analysis ◽  
Pneumatic Actuators ◽  
Fused Deposition ◽  
Manufacturing Applications ◽  
Manufacturing Technologies

This paper describes the results of research projects developed at the University of L’Aquila by the research group of the authors in the field of biomedical engineering, which have seen an important use of additive manufacturing technologies in the prototyping step and, in some cases, also for the realization of preindustrialization prototypes. For these projects, commercial 3D printers and technologies such as fused deposition modelling (FDM) were used; the most commonly used polymers in these technologies are acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). The research projects concern the development of innovative actuators, such as pneumatic muscles and soft pneumatic actuators (SPAs), the development of active orthoses, such as a lower limb orthosis and, finally, the development of a variable-stiffness grasper to be used in natural orifice transluminal endoscopic surgery (NOTES). The main aspects of these research projects are described in the paper, highlighting the technologies used such as the finite element analysis and additive manufacturing.

Metal bellow hydroforming using additive manufactured die: a case study

2019 ◽  
Vol 25 (4) ◽  
pp. 765-774 ◽  
Author(s):  
Prithvirajan R. ◽  
Sugavaneswaran M. ◽  
Sathishkumar N. ◽  
Arumaikkannu G.
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Successful Outcome ◽  
Fused Deposition Modelling ◽  
Element Analysis ◽  
Content Type ◽  
Fused Deposition ◽  
Production Run ◽  
Fea Simulation ◽  
Die Material ◽  
Metal Bellow

Purpose Custom-designed metal bellows require alternate ways to produce the die to shorten lead time. The purpose of this study is to explore the possibility of using Additive Manufactured (AM) polymer die as direct rapid tool (RT) for metal bellow hydroforming. Design/methodology/approach Finite element analysis (FEA) was used to simulate bellow forming and to evaluate the compatibility of AM die. Fused deposition modelling (FDM) technique is used to fabricate die with Acrylonitrile Butadiene Styrene (ABS) material. To validate, the width of the metal bellow convolutions obtained from the FEA simulation is compared with convolution formed during the experiment. Findings FDM-made die can be used for a short production run of bellow hydroforming. FEA simulation shows that stress developed in some regions of die is less and these regions have potential for material reduction. Use of RT for this particular application is limited by the die material, forming pressure, width, convolution span and material of bellow. This supports the importance of FEA validation of RT before fabrication to evaluate and redesign die for the successful outcome of the tool. Research limitations/implications The given methodology may be followed to design a RT with minimum material consumption for bellow forming application. Whenever there is a change in bellow design or the die material, simulation has to be done to evaluate the capability of the die. As this study was focused on a short production run for manufacturing one or few bellows, the die life is not a significant factor. Originality/value This paper demonstrates about rapid tooling for metal bellow manufacturing using FDM technique for low volume production. Further, FEA is used to identify low stress regions and redesign the die for material reduction before die manufacturing. AM die can be used for developing customized metal bellow for applications such as defense, aerospace, automobiles, etc.

An Investigation of the Ring Hoop Tension Test for Anisotropic Tubes

2014 ◽  
Author(s):  
Christopher P. Dick ◽  
Yannis P. Korkolis
Keyword(s):  
Contact Pressure ◽  
Tension Test ◽  
Negligible Effect ◽  
Image Correlation ◽  
Element Analysis ◽  
Material Response ◽  
Full Field ◽  
Al 6061 ◽  
Full Field Measurement ◽  
Nominal Thickness

The ring hoop tension test (RHTT) is investigated experimentally and numerically to determine its validity and limitations in predicting the hoop response of materials in tubular form. Our experiments involved RHT-Testing of Al-6061-T4 tubes. Digital image correlation (DIC) was used to capture the strain evolution in the gage section of the specimens, giving a full-field measurement of the strains. The local hoop stress-strain response of the material was assessed in this way. Finite element analysis was used to further investigate the effects of friction, eccentricity and contact pressure on the recorded response. Friction was found to have a negligible effect on the recorded response for friction coefficient values of 0.01 and lower. However, it was found that larger values of friction may render the test meaningless. Tube eccentricity of the magnitude present in the tubes tested here (±4% of the nominal thickness) was determined to have no effect on the material response. It was also determined that tubes should not be turned to a uniform thickness as this may induce machining damage and release the existing residual stresses, thus causing error in determining the tube response in the hoop direction. The contact pressure was found to not significantly affect the state of uniaxial tension in the specimen and thus to have a negligible effect on the material response. By comparing the hoop with the axial response, the material anisotropy of the Al-6061-T4 tubes was established.

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