scholarly journals Filling behavior of micro-ribs on injection molded parts depending on micro-structure orientation and processing parameters

Author(s):  
T. Lucyshyn ◽  
M. Burgsteiner ◽  
G. Graninger ◽  
C. Holzer
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.


Mechanik ◽  
2018 ◽  
Vol 91 (1) ◽  
pp. 36-38 ◽  
Author(s):  
Przemysław Poszwa ◽  
Paweł Brzęk ◽  
Marek Szostak

Shear heating effect that occurs in melted polymers can cause serious quality problems with production of injection molded parts. The source of this effect is high viscosity of polymers and low thermal conductivity what leads to significant temperature gradients at the cross section of runners. In this work the influence of processing parameters on this phenomenon for difference runner diameters and lengths was presented for two polymers that have different thermal sensitivity.


Author(s):  
Han-Xiong Huang ◽  
Can Yang ◽  
Kun Li

Four processing parameters, including compression force, compression time, compression distance, and delay time, were investigated in terms of their effects on the fiber orientation in injection-compression molded (ICM) short-fiber-reinforced polypropylene parts. The results reveal that the fiber orientation pattern in ICM parts is different from that in conventional injection molded parts. Compression force plays an important role in determining the fiber orientation, whereas the effect of compression time can be neglected. Moreover, the fiber orientation changes obviously in the width direction, with most fibers arranging orderly in the flow direction at positions near the mold cavity wall.


2018 ◽  
Vol 62 (4) ◽  
pp. 284-291 ◽  
Author(s):  
László Zsíros ◽  
József Gábor Kovács

In this paper we are presenting a novel method for color inhomogeneity evaluation. We proved that this method has a higher than 95 % linear correlation coefficient if results are correlated with human visual evaluations.We applied this evaluation method to analyze the homogenization in the injection molding process, therefore we measured the homogenization properties of various solid phase masterbatches on injection molded parts. We tested the effects of the processing parameters of injection molding and analyzed various dynamic and static mixers as well. We have also measured the influence of the mold surface texture on the sensation of inhomogeneities on the part surface.We have carried out our tests on an injection grade ABS material using various masterbatches. The method was based on the digitization of the molded flat specimens. The images of these specimens were evaluated with an own developed formula using the CIELAB color space resulting high correlation with human visual inspections.


Author(s):  
Alan M. Tom ◽  
Aleksandar K. Angelov ◽  
John P. Coulter

The primary objective of this study, through a scientific experimental investigation, was to determine optimum injection molding processing parameters on semi-crystalline materials HDPE and POM focusing on mechanical properties, obtained thru the use of a nano-indenter, of micro gears being manufactured on non-heated and heated mold bases. A secondary objective was to initiate a similar experimental study using amorphous COC material. Taguchi’s method utilizing an L-9 orthogonal array was used to determine the effects of Tnoz, Tmold, Pinj, Vinj, Ppack, and tpack injection molding processing parameters. A nano-indenter was used to determine investigated mechanical properties on final injection molded parts that included stiffness (S), reduced modulus (Er), and hardness (H). Results showed HDPE, POM and COC, heated mold experiments exhibiting increases in mechanical properties S, Er, and H, on the order of 1.2–4.0 times those of non-heated molding trials. Decreases in optimum molding conditions for Tnoz, Pinj, and Ppack was also observed for heated molding trials. The highest mold temperatures and injection pressures tested did not produce greatest optimum molding conditions. However, largest packing times tested produced optimum molding conditions.


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.


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

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