Effect of Tool Path Parameters on Part Porosity in Fused Filament Fabrication of Poly(Ethylene-co-Trimethylene Terephthalate)

2018 ◽  
Vol 382 ◽  
pp. 99-103
Author(s):  
Robert Bail
Keyword(s):  
Layer Thickness ◽  
Tool Path ◽  
Air Gap ◽  
Engineering Material ◽  
Fused Filament Fabrication ◽  
Additive Fabrication ◽  
Food Applications ◽  
Road Width ◽  
Trimethylene Terephthalate ◽  
Poly Ethylene

Poly(ethylene-co-trimethylene terephthalate) is an engineering material that has recently gained attention for use in fused filament fabrication (FFF). Although the properties of this thermoplastic are well suited for this process, the porosity of the components made remains a barrier to wider use of this approach in the additive fabrication of tight components for medical and food applications. This study investigated the effects of four tool path parameters of the FFF process – road width, air gap, layer thickness, and outer contours – on the void fraction in the structures made. It was revealed that the porosity was reduced from above 9% to below 2% when the extrusion rate was increased from initially 5.00 mm3/s to at least 5.75 mm3/s. A similar outcome was observed when a negative air gap between two adjacent strands of -15% or less was applied. In addition, these results were obtained without extending the print times. By contrast, altering the layer thickness and number of contours had only marginal or no effects on part porosity.

Influence of processing parameters on creep and recovery behavior of FDM manufactured part using definitive screening design and ANN

2017 ◽  
Vol 23 (6) ◽  
pp. 998-1010 ◽  
Author(s):  
Omar Ahmed Mohamed ◽  
Syed Hasan Masood ◽  
Jahar Lal Bhowmik
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Air Gap ◽  
Content Type ◽  
Screening Design ◽  
Definitive Screening ◽  
Raster Angle ◽  
Road Width ◽  
Recoverable Compliance ◽  
The Relationship

Purpose The purpose of this paper is to investigate the effect of process parameters of fused deposition modelling (FDM) 3D printing process on viscoelastic responses (creep compliance and recoverable compliance) of FDM built parts using a novel experimental design technique. Design/methodology/approach As part of the process characterization, a recently developed class of three-level design methodology – definitive screening design (DSD) – was used in this study to fit a second-order polynomial regression model. Artificial neural network (ANN) was also used to determine the optimal process parameters to improve creep compliance and recoverable compliance. The relationship between layer thickness, air gap, raster angle, build orientation, road width, number of contours and creep performance of FDM fabricated part was thereafter established empirically. Scanning electron microscope (SEM) is used to examine and characterize the morphology of the structures for some samples. Findings This study found that the creep resistance of FDM-manufactured part is significantly influenced by layer thickness, air gap, raster angle and number of contours and it can be improved by optimizing the settings of the selected parameters. The relationship between FDM process parameters and creep properties was determined, with the best creep performance observed by using 0.127 mm of layer thickness, zero air gap, zero raster angle, build orientation of 17.188°, road width of 0.4572 mm and 10 contours. Finally, the result is verified by confirmation experiments. The results prove that a DSD is a very effective design in characterizing the influence of process parameters on creep properties of FDM-built part at the lowest cost. Originality/value The originality of this paper lies in characterizing and optimizing the effect of process parameters on creep performance of FDM manufactured part that has not been studied in all previous studies. The paper highlights, for the first time, how the application of DSD can overcome most of the limitations encountered in the conventional techniques. This study can be used as a guide to the different additive manufacturing users of various industries and the results provide a good technical database on how FDM process parameters influence the creep performance of manufactured parts.

Extrusion Temperature and Flow Rate Effects on Tensile Properties of Additively Processed Poly(Ethylene-co-Trimethylene Terephthalate)

2018 ◽  
Vol 382 ◽  
pp. 104-108
Author(s):  
Robert Bail
Keyword(s):  
Tensile Properties ◽  
Flow Rate ◽  
Tensile Modulus ◽  
Volumetric Flow Rate ◽  
Extrusion Temperature ◽  
Fused Filament Fabrication ◽  
Effective Strategies ◽  
Rate Effects ◽  
Trimethylene Terephthalate ◽  
Poly Ethylene

This study investigated the effects of the extrusion temperature and volumetric flow rate settings in a fused filament fabrication (FFF) process on the tensile properties of specimens made of poly(ethylene-co-trimethylene terephthalate). The tensile strength almost doubled from 13.5 MPa at 230°C to 26.7 MPa at 260°C extrusion temperature, while the elongation at break improved to 5.4% and the tensile modulus rose to 641.8 MPa at the highest temperature. Similar observations were made when the extrusion flow rate was augmented to 115% of the initial value, with part strength greatly improving to 795.9 MPa and part elasticity increasing by 22%. These results illustrate two effective strategies to enhance the mechanical properties of components made in an engineering material that is increasingly being utilized in filament-based 3D printing.

scholarly journals Optimization of the 3D Printing Parameters for Tensile Properties of Specimens Produced by Fused Filament Fabrication of 17-4PH Stainless Steel

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 774 ◽  
Author(s):  
Damir Godec ◽  
Santiago Cano ◽  
Clemens Holzer ◽  
Joamin Gonzalez-Gutierrez
Keyword(s):  
Stainless Steel ◽  
3D Printing ◽  
Tensile Properties ◽  
Layer Thickness ◽  
Flow Rate ◽  
Three Dimensional ◽  
Steel Powder ◽  
Extrusion Temperature ◽  
Fused Filament Fabrication ◽  
Printing Parameters

Fused filament fabrication (FFF) combined with debinding and sintering could be an economical process for three-dimensional (3D) printing of metal parts. In this paper, compounding, filament making, and FFF processing of feedstock material with 55% vol. of 17-4PH stainless steel powder in a multicomponent binder system are presented. The experimental part of the paper encompasses central composite design for optimization of the most significant 3D printing parameters (extrusion temperature, flow rate multiplier, and layer thickness) to obtain maximum tensile strength of the 3D-printed specimens. Here, only green specimens were examined in order to be able to determine the optimal parameters for 3D printing. The results show that the factor with the biggest influence on the tensile properties was flow rate multiplier, followed by the layer thickness and finally the extrusion temperature. Maximizing all three parameters led to the highest tensile properties of the green parts.

Rheology of poly(lactic acid)/poly(trimethylene terephthalate) blends compatibilized by clay or maleic anhydride-grafted poly(ethylene-octene) elastomer

2019 ◽  
Vol 39 (3) ◽  
pp. 248-253
Author(s):  
Gwo-Geng Lin ◽  
Yi-Hu Song ◽  
Chao-Tsai Huang ◽  
Marek Sipos ◽  
Zhaokang Tu
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Low Frequency ◽  
Complex Viscosity ◽  
Fold Increase ◽  
Poly Lactic Acid ◽  
Morphology Evolution ◽  
Cloisite 30B ◽  
Trimethylene Terephthalate ◽  
Poly Ethylene

Abstract Blends of two biobased polymers, poly(lactic acid) and poly(trimethylene terephthalate) (PTT), were compatibilized with either maleic anhydride-grafted poly(ethylene-octene) (mPOE) or organically modified clay (Cloisite 30B). Dynamic rheological measurements revealed that the mPOE inclusion resulted in a four-fold increase in viscosity relative to the noncompatibilized blends. By loading 3 wt% Cloisite 30B, the storage moduli of the blends showed a distinct solid-like behavior and high complex viscosity in the low-frequency region, which can be interpreted by the reduced sizes of the PTT phase evidenced from the scanning electron microscopy (SEM) micrography. A temperature sweep of the viscosity of the blends starting from 180°C revealed that the existence of an unmelted PTT dispersed phase might impede the decline in viscosity with increasing temperature near the melting point of PTT. The introduced compatibilizers can restrict the temperature-dependent morphology evolution, and the use of the 3 wt% 30B clay can prohibit the morphology evolution during the temperature sweep.

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