Correlation Between Mechanical Properties in Standard Test Specimens and Injection Molded Thin-Wall Parts

2013 ◽  
Author(s):  
Laurentiu I. Sandu ◽  
Felicia Stan ◽  
Catalin Fetecau
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Injection Molding ◽  
Process Conditions ◽  
Thin Wall ◽  
Optimal Process ◽  
Melt Temperature ◽  
Molded Parts ◽  
Injection Molded

In this paper, we investigated the effect of injection molding parameters on the mechanical properties of thin-wall injection molded parts. A four-factor (melt temperature, mold temperature, injection speed and packing pressure) and three-level fractional experimental design was performed to investigate the influence of each factor on the mechanical properties and determine the optimal process conditions that maximize the mechanical properties of the part using the signal-to-noise (S/N) ratio response. The mechanical properties (e.g., elastic modulus, yield strength and strain at break) were measured by tensile tests at room temperature, at a crosshead speed of 5 mm/min, and compared with those of the injection-molded specimens. The experimental results showed that the tensile properties were highly dependent on the injection molding parameters, regardless of the type of the specimens. The values of Young modulus and yield strength of the injection-molded specimens were lower than those of the injection-molded parts, while the elongation at break was considerably lower for the injection-molded parts. The optimal process conditions were strongly dependent on the measured performance quantities (elastic modulus, yield strength and strain at break).

scholarly journals Effects of Injection Molding Screw Tips on Polymer Mixing

2018 ◽  
Vol 62 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Dániel Török ◽  
József Gábor Kovács
Keyword(s):  
Injection Molding ◽  
Processing Parameters ◽  
Raw Material ◽  
Molding Machine ◽  
Surface Color ◽  
Melt Temperature ◽  
Injection Molding Machine ◽  
Aesthetic Appearance ◽  
Molded Parts ◽  
Injection Molded

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.

Experimental study on influence of molding parameters on self-reinforcement characteristics of polymer co-injection molding

2020 ◽  
Vol 40 (3) ◽  
pp. 278-289
Author(s):  
Yong Lu ◽  
Kaiyu Jiang ◽  
Minjie Wang ◽  
Yan Zhang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Injection Molding ◽  
Theoretical Study ◽  
Least Square ◽  
Skin Thickness ◽  
Melt Temperature ◽  
Dimensionless Equation ◽  
Mechanism Model ◽  
Micro Morphology

AbstractIn this paper, self-reinforced samples with different mechanical properties were obtained by adjusting the molding parameters by co-injection molding technology, and the micro-morphology of these samples was observed. Then, using structured statistical methods, the analysis of variance and response surface methodology were used to study the effects of various molding variables on the morphology and properties of the materials, and to determine the most important molding variables and their interaction relationships. Finally, the associated experimental data were fitted by the least square minimization program, and the parameters in the fitting equation were dimensionless to obtain the correlative dimensionless equation. The purpose was to establish the mechanism model of the influence of the molding parameters on the co-injection self-reinforced sample and to objectively analyze its mechanism. It was found that the melt temperature is the most important factor affecting the morphology and mechanical properties. The highly oriented skin thickness is the most important factor in determining the tensile properties of the sample. The change in crystallinity is the most important factor in relation to the elastic modulus. Through the establishment of the relevant dimensionless equations, the theoretical study on the tensile strength and elastic modulus of the co-injection self-reinforced samples of the molding parameters was preliminarily realized.

An Experimental Investigation of a Micro Injection Molded Mechanical Device

2005 ◽  
Author(s):  
Alan M. Tom ◽  
Aleksandar K. Angelov ◽  
John P. Coulter
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Injection Molding ◽  
Processing Parameters ◽  
Primary Objective ◽  
Crystalline Materials ◽  
Reduced Modulus ◽  
Molded Parts ◽  
Secondary Objective ◽  
Injection Molded

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.

Experimental Study on the Crystallinity and Mechanical Properties of the Injection Molded Polypropylene

2011 ◽  
Vol 239-242 ◽  
pp. 2809-2812 ◽  
Author(s):  
Xiao Xun Zhang ◽  
Luo Wang ◽  
Qiu Hui Liao
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Diffraction Method ◽  
Processing Conditions ◽  
Mould Temperature ◽  
X Ray Diffraction ◽  
Melt Temperature ◽  
X Ray ◽  
Injection Speed ◽  
Injection Molded

Polypropylene specimens were made by the injection molding experiments under different processing conditions. The crystallinity of each polypropylene specimen was obtained using the X-ray diffraction method. The effects of the injection molding processes on the crystallinity of polypropylene were revealed: (1) the crystallinity decreases as the melt temperature increases, and the higher the melt temperature, the slower the crystallinity decreases, (2) the crystallinity decreases as the mould temperature increases, and the higher the mould temperature, the faster the crystallinity decreases, (3) the crystallinity increases as the injection speed increases, and the larger the injection speed, the faster the crystallinity increases. By the tensile experiments of the injection molded specimens, it is also found that the crystallinity has a major impact on the mechanical properties of polypropylene. The yield strength and tensile strength of polypropylene specimens increase as the crystallinity increases.

Mechanical Properties of PMMA/PC Blend by Injection Molding Process

2020 ◽  
Vol 863 ◽  
pp. 67-71
Author(s):  
Van Thanh Hoang ◽  
Duc Binh Luu ◽  
Quang Bang Tao ◽  
Chao Chang Arthur Chen
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Mold Temperature ◽  
Cooling Time ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Molding Process ◽  
Optical Elements ◽  
Melt Temperature ◽  
Significant Parameter

Polycarbonate (PC) has the high impact strength, whereas Polymethylmethacrylate (PMMA) possesses the high tensile strength. Both of them have been widely used for optical elements in illumination. This paper aims to investigate mechanical properties including tensile and impact strengths of PMMA/PC blend with 50 percent of PC concentration by injection molding process. Tensile and impact specimens were designed following ASTM, type V and were fabricated by injection molding process. Taguchi technique was employed to figure out the optimal process conditions for maximum tensile and impact strengths. The processing conditions such as melt temperature, mold temperature, packing pressure and cooling time were applied and each factor has three levels. As a results, melt temperature has been found to be the most significant parameter for both tensile and impact strengths and cooling time is the least significant parameter for the mechanical properties.

Effects of Gate Locations on the Tensile Strength of Injection Molded Weld Lines

2013 ◽  
Vol 561 ◽  
pp. 64-69
Author(s):  
Yu Mei Ding ◽  
Xiao Hua Wang ◽  
Peng Cheng Xie ◽  
You Chen Zhang ◽  
Wei Min Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Test ◽  
Injection Pressure ◽  
Melt Temperature ◽  
Injection Speed ◽  
Appearance Quality ◽  
Study Results ◽  
Molded Parts ◽  
Injection Molded

As unfavorable molding defect, weld lines often result in reduced mechanical properties and poor appearance quality of injection molded parts. In this present work, effects of gate locations on the tensile strength of weld lines were investigated by changing the distances between two gates in 10mm, 20mm and 25mm, respectively. Test specimens were prepared with an all-electrical injection molding machine under different process parameters (injection speed, injection pressure and melt temperature). Visualization method and scanning electron microscope (SEM) were employed to further discuss mechanical test results. Study results indicated that tensile strength of injection molded weld lines was lessened as the increase of gate distances. Higher injection speed, higher injection pressure and lower melt temperature induced to lower weldline tensile strength whatever the gate locations were. Study results also illustrated that it was gate location rather than molding conditions had the most decisive influence on the weldline mechanical properties.

scholarly journals Effect of Injection Molding Melt Temperatures on PLGA Craniofacial Plate Properties during In Vitro Degradation

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Liliane Pimenta de Melo ◽  
Gean Vitor Salmoria ◽  
Eduardo Alberto Fancello ◽  
Carlos Rodrigo de Mello Roesler
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Melt Temperature ◽  
In Vitro Degradation ◽  
Molecular Weights ◽  
Ft Ir ◽  
Injection Molded ◽  
Higher Temperature ◽  
Lower Temperature

The purpose of this article is to present mechanical and physicochemical properties during in vitro degradation of PLGA material as craniofacial plates based on different values of injection molded temperatures. Injection molded plates were submitted to in vitro degradation in a thermostat bath at 37 ± 1°C by 16 weeks. The material was removed after 15, 30, 60, and 120 days; then bending stiffness, crystallinity, molecular weights, and viscoelasticity were studied. A significant decrease of molecular weight and mechanical properties over time and a difference in FT-IR after 60 days showed faster degradation of the material in the geometry studied. DSC analysis confirmed that the crystallization occurred, especially in higher melt temperature condition. DMA analysis suggests a greater contribution of the viscous component of higher temperature than lower temperature in thermomechanical behavior. The results suggest that physical-mechanical properties of PLGA plates among degradation differ per injection molding temperatures.

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

2015 ◽  
Vol 76 (7) ◽  
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.

Micro-Injection Molding of Polymer Nanocomposites Composition-Process-Properties Relationship

2021 ◽  
Vol 36 (3) ◽  
pp. 276-286
Author(s):  
Z. Dekel ◽  
S. Kenig
Keyword(s):  
Mechanical Properties ◽  
Plug Flow ◽  
Volume Resistivity ◽  
Process Conditions ◽  
Polyamide 66 ◽  
Fountain Flow ◽  
Microinjection Molding ◽  
Injection Molded ◽  
Composition Process ◽  
Rheological Percolation

Abstract The mechanical, electrical, thermal, and rheological properties of micro injection molded nanocomposites comprising 2% and 5% carbon nanotubes (CNTs) incorporated in polycarbonate (PC), and polyamide 66 (PA) were studied. The design of experiments method was used to investigate the composition-process – properties relationship. Results indicated that the process variables significantly affected the flow patterns and resulting morphology during the filling stage of the microinjection molding (lIM) process, using 0.45 mm diameter lIM samples. Two distinct flow regimes have been identified in lIM using the low cross-section samples. The first was a conventional “fountain flow,” which resulted in a skin/core structure and reduced volume resistivity up to 10 X cm in the case of 5% CNTs and up to 100 X cm in 2% CNTs, in both polymers, respectively. In addition, inferior mechanical properties were obtained, attributed to polymer degradation under high shear rate conditions, when practicing high injection speeds, high mold temperatures, and high screw rotation velocities. The second was a “plug flow” due to wall slippage, obtained under low injection speeds, low mold temperatures, and low rotation velocities, leading to a substantial increase in modulus of elasticity (60%) with increased electrical resistivity up to 103 X cm for 5% CNTs and 105 X cm for 2% CNTs, respectively. The rheological percolation threshold was obtained at 2% CNTs while the electrical threshold was attained at 0.4% CNTs, in both polymers. It was concluded that in lIM, the process conditions should be closely monitored. In the case of high viscous heating, degradation of mechanical properties was obtained, while skin- core morphology formation enhanced electrical conductivity.

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