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

2019 ◽  
Author(s):  
Y. Spoerer ◽  
C. Blanco ◽  
M. Zimmermann ◽  
M. Berger ◽  
I. Kuehnert
Keyword(s):  
Crystalline Polymers ◽  
Molded Parts ◽  
Injection Molded

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

e-Polymers ◽  
2009 ◽  
Vol 9 (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.

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

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.

A Study on the Birefringence Measurement in Injection Molded Parts Using Two Different Laser Sources and R-G-B Separation of White Light

2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon
Keyword(s):  
White Light ◽  
Low Cost ◽  
Main Idea ◽  
Injection Molding Process ◽  
Molding Process ◽  
Laser Method ◽  
High Productivity ◽  
Molded Parts ◽  
Injection Molded ◽  
Plastic Parts

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.

scholarly journals Silane-Functionalized Sheep Wool Fibers from Dairy Industry Waste for the Development of Plasticized PLA Composites with Maleinized Linseed Oil for Injection-Molded Parts

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2523
Author(s):  
Franciszek Pawlak ◽  
Miguel Aldas ◽  
Francisco Parres ◽  
Juan López-Martínez ◽  
Marina Patricia Arrieta
Keyword(s):  
Linseed Oil ◽  
Microstructural Analysis ◽  
Dairy Industry ◽  
Poly Lactic Acid ◽  
Industry Waste ◽  
Wool Fibers ◽  
Molded Parts ◽  
Silane Modification ◽  
Injection Molded ◽  
Sheep Wool

Poly(lactic acid) (PLA) was plasticized with maleinized linseed oil (MLO) and further reinforced with sheep wool fibers recovered from the dairy industry. The wool fibers were firstly functionalized with 1 and 2.5 phr of tris(2-methoxyethoxy)(vinyl) (TVS) silane coupling agent and were further used in 1, 5, and 10 phr to reinforce the PLA/MLO matrix. Then, the composite materials were processed by extrusion, followed by injection-molding processes. The mechanical, thermal, microstructural, and surface properties were assessed. While the addition of untreated wool fibers to the plasticized PLA/MLO matrix caused a general decrease in the mechanical properties, the TVS treatment was able to slightly compensate for such mechanical losses. Additionally, a shift in cold crystallization and a decrease in the degree of crystallization were observed due to the fiber silane modification. The microstructural analysis confirmed enhanced interaction between silane-modified fibers and the polymeric matrix. The inclusion of the fiber into the PLA/MLO matrix made the obtained material more hydrophobic, while the yellowish color of the material increased with the fiber content.

scholarly journals Development of a novel color inhomogeneity test method for injection molded parts

2014 ◽  
Vol 37 ◽  
pp. 112-116 ◽  
Author(s):  
L. Zsíros ◽  
A. Suplicz ◽  
G. Romhány ◽  
T. Tábi ◽  
J.G. Kovács
Keyword(s):  
Test Method ◽  
Molded Parts ◽  
Injection Molded

Prediction and measurement of residual stresses in injection molded parts

2001 ◽  
Vol 2 (4) ◽  
pp. 203-211 ◽  
Author(s):  
Young Il Kwon ◽  
Tae Jin Kang ◽  
Kwansoo Chung ◽  
Jae Ryoun Youn
Keyword(s):  
Residual Stresses ◽  
Molded Parts ◽  
Injection Molded

Geometry-Based Index for Predicting Sink Mark in Plastic Parts

1991 ◽  
Author(s):  
Kurt Beiter ◽  
Kosuke Ishii ◽  
Lee Hornberger
Keyword(s):  
Process Conditions ◽  
Plastic Part ◽  
Design Rules ◽  
Packing Pressure ◽  
Molded Parts ◽  
Injection Molded ◽  
Form Features ◽  
Plastic Parts ◽  
Sink Mark

Abstract This paper describes the development of geometry-based indices that predict sink mark depth in injection molded parts. Plastic part designers need such indices to incorporate manufacturability concerns at the conceptual stage of design. These indices apply to several form features so engineers do not have to check different design rules for each geometry element. First, we propose a geometry-based sink index that can be used to predict sink mark depth as a function of process conditions such as packing pressure. Next, we explain how this relationship is identified through experiments. We also describe HyperDesign/Plastics, a Macintosh-based design aid that incorporates the sink index.

Estimation of diffusion and solubility coefficients for water and CO2 in reaction injection molded parts

1996 ◽  
Vol 17 (5) ◽  
pp. 649-655 ◽  
Author(s):  
Deborah F. Mielewski ◽  
Nitin R. Anturkar ◽  
David R. Bauer
Keyword(s):  
Molded Parts ◽  
Injection Molded ◽  
Solubility Coefficients
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