Experimental Study on the Warpage and Tensile Strength of Additively Manufactured Semi-Crystalline Polyamide 6

Volume 1: Additive Manufacturing; Manufacturing Equipment and Systems; Bio and Sustainable Manufacturing ◽

10.1115/msec2019-2845 ◽

2019 ◽

Author(s):

Konstantin Struebig ◽

Andreas Schröffer ◽

Tim C. Lueth

Keyword(s):

Mechanical Properties ◽

Experimental Study ◽

Tensile Tests ◽

Polyamide 6 ◽

High Tendency ◽

Manufacturing Method ◽

Crystalline Polymers ◽

Basic Model ◽

Molded Parts ◽

Injection Molded

Abstract Semi-crystalline polymers offer great mechanical properties and are ubiquitously found in everyday life. Despite of this, they are not yet widespread among additive manufacturing processes, due to their high tendency to warp. This leads to unstable build processes and dimensionally inaccurate parts, which greatly reduces their usability. This paper describes the findings of an experimental study designed to identify relevant parameters that affect the warpage and investigate the influence of the manufacturing method on the mechanical properties of semi-crystalline PA6. The first experiment investigates the effect of water absorption over time, measuring weight and curling of 64 specimens over three weeks. The second part of this study focuses on the changes in geometry caused by the warpage by evaluating a basic model for simple part geometries. At last, a tension test was conducted and the results were compared to injection molded parts of the same material. The results indicate, that while the absorption of water plays an important role in the warpage of hydrophilic polymers like PA6, other environmental factors also have a significant influence. The model evaluation showed, that the warpage geometry of the tested parts can be approximated with only three parameters for very simple parts, if there are no irregularities in the manufacturing process. The tensile tests revealed, that the additively manufactured specimens reach up to 85.9% of the strength of the injection molded reference parts, most likely due to imperfect filling and reduced density. Overall, this study provides an insight into the challenges of additively manufacturing semi-crystalline polymers and the potential of PA6 as a tougher alternative to the common materials.

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MECHANICAL AND MORPHOLOGICAL PROPERTIES OF POLYAMIDE 12 COMPOSITE FOR POTENTIAL BIOMEDICAL IMPLANT: INJECTION MOLDING AND DESKTOP 3D PRINTER

Jurnal Teknologi ◽

10.11113/jt.v76.5717 ◽

2015 ◽

Vol 76 (7) ◽

Cited By ~ 1

Author(s):

Tuan Noraihan Azila Tuan Rahim ◽

Hazizan Md Akil ◽

Abdul Manaf Abdullah ◽

Dasmawati Mohamad ◽

Zainul Ahmad Rajion

Keyword(s):

Mechanical Properties ◽

Injection Molding ◽

Morphological Properties ◽

3D Printer ◽

Fused Filament Fabrication ◽

Manufacturing Method ◽

Biomedical Implant ◽

Polyamide 12 ◽

Molded Parts ◽

Injection Molded

Fused filament fabrication is a filament based rapid prototyping process, which offers the possibility of new polymer material for invention of biomedical implant. This study represents an investigation on a preparation and characterization of new polyamide 12 reinforced with 20 wt% of zirconium dioxide and hydroxyapatite by desktop 3D printer in comparison with conventional manufacturing method, injection molding. Polyamide 12 composite was compounded, pelletized and filament-extruded prior to apply to a 3D printer. Sample prototypes from the new polyamide composite have been successfully made and tested. Mechanical (flexural and impact) and morphological properties were evaluated and compared. From the results, the printed polyamide composite exhibited lower mechanical properties than injection molded due to the formation of porosity, laminate weakness and low pressure during printing. Although the mechanical properties of printed parts were lower than molded parts, but the capability of 3D printer to fabricate any customized 3D object could lead to the bright future and great contribution in this area, while at the same time many improvements can be made for the future works.

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The tensile behaviour of biaxial and triaxial braided fabrics

Journal of Industrial Textiles ◽

10.1177/1528083716654469 ◽

2016 ◽

Vol 47 (8) ◽

pp. 2184-2204 ◽

Cited By ~ 9

Author(s):

Duchamp Boris ◽

Legrand Xavier ◽

Soulat Damien

Keyword(s):

Mechanical Properties ◽

Experimental Study ◽

Mechanical Behaviour ◽

Tensile Tests ◽

Uniaxial Tensile ◽

Tensile Behaviour ◽

Linear Mass ◽

Double Peak ◽

Specific Behaviour ◽

Braiding Angle

The tensile behaviour of braid reinforcement is classically described by the behaviour of composite elaborated from these reinforcements. Few studies concern the tensile behaviour of braided fabrics. In this paper biaxial and triaxial braids are manufactured on a braiding loom. The evolution of key parameters as linear mass and braiding angle in function of process parameters is presented. Braid reinforcements are characterized in uniaxial tensile. The mechanical behaviour is analysed and compared in function of the braiding angle, but also different kinds of braid are considered. A specific behaviour called “double-peak” is identified for triaxial braids which have a higher braiding angle. The evolution of the braiding angle measured during tensile tests gives a comprehension on the mechanical behaviour of dry braids. Associated with this experimental study, an analytical model is also proposed, to predict mechanical properties of braid reinforcements.

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Deposition-induced effects of isotactic polypropylene and polycarbonate composites during fused deposition modeling

Rapid Prototyping Journal ◽

10.1108/rpj-12-2015-0189 ◽

2017 ◽

Vol 23 (5) ◽

pp. 869-880 ◽

Cited By ~ 19

Author(s):

Ying-Guo Zhou ◽

Bei Su ◽

Lih-sheng Turng

Keyword(s):

Mechanical Properties ◽

Design Methodology ◽

Fused Deposition Modeling ◽

Content Type ◽

Fused Deposition ◽

Close Relationship ◽

Molded Parts ◽

Deposition Modeling ◽

Injection Molded ◽

First Time

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

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Morphology-property behavior of semi crystalline polymers in injection molded parts

10.1063/1.5084846 ◽

2019 ◽

Author(s):

Y. Spoerer ◽

C. Blanco ◽

M. Zimmermann ◽

M. Berger ◽

I. Kuehnert

Keyword(s):

Crystalline Polymers ◽

Molded Parts ◽

Injection Molded

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Prediction of crystallinity profile and eject time of injection molded parts using finite element method (FEM)

e-Polymers ◽

10.1515/epoly.2009.9.1.81 ◽

2009 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Mehdi Mostafaiyan ◽

Farhad Sharif

Keyword(s):

Finite Element ◽

Degree Of Crystallinity ◽

Element Analysis ◽

Melt Temperature ◽

Crystalline Polymers ◽

Molded Parts ◽

Time Part ◽

Injection Molded ◽

The Subject

AbstractQuality of injection molded parts of semi-crystalline polymers has been the subject of intense interest from both analytical and industrial points of view. Crystallinity profile plays an important role in determining mechanical properties of a part and its quality. Therefore it is important to analyze the effect of injection molding parameters on the crystallinity profile of the molded parts. In this study, finite element analysis has been used to solve the equations of mass, momentum, and energy conservation simultaneously with the equation of crystallization kinetics to predict melt front, its solidification and crystallinity profile. The results from our numerical analysis have been compared with the reported experimental results. Furthermore, progress of the crystallization is proposed to be a proper criterion for estimation of the eject time. Finally, the effects of mold and melt temperature on the eject time; part temperature and average degree of crystallinity, for a specific compound are also presented.

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