Statistical Approach to Analyze the Warpage, Shrinkage and Mechanical Strength of Injection Molded Parts

2016 ◽  
Vol 31 (3) ◽  
pp. 376-384 ◽  
Author(s):  
N. Hadler Marins ◽  
F. Bier de Mello ◽  
R. Marques e Silva ◽  
F. Aulo Ogliari
2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon

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.


2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2523
Author(s):  
Franciszek Pawlak ◽  
Miguel Aldas ◽  
Francisco Parres ◽  
Juan López-Martínez ◽  
Marina Patricia Arrieta

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.


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

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

Author(s):  
Kurt Beiter ◽  
Kosuke Ishii ◽  
Lee Hornberger

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.


1996 ◽  
Vol 17 (5) ◽  
pp. 649-655 ◽  
Author(s):  
Deborah F. Mielewski ◽  
Nitin R. Anturkar ◽  
David R. Bauer

2018 ◽  
Vol 62 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Dániel Török ◽  
József Gábor Kovács

In all fields of industry it is important to produce parts with good quality. Injection molded parts usually have to meet strict requirements technically and aesthetically. The aim of the measurements presented in our paper is to investigate the aesthetic appearance, such as surface color homogeneity, of injection molded parts. It depends on several factors, the raw material, the colorants, the injection molding machine and the processing parameters. In this project we investigated the effects of the injection molding machine on surface color homogeneity. We focused on injection molding screw tips and investigated five screw tips with different geometries. We produced flat specimens colored with a masterbatch and investigated color homogeneity. To evaluate the color homogeneity of the specimens, we used digital image analysis software developed by us. After that we measured the plastication rate and the melt temperature of the polymer melt because mixing depends on these factors. Our results showed that the screw tips (dynamic mixers) can improve surface color homogeneity but they cause an increase in melt temperature and a decrease in the plastication rate.


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