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.

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.

The effects of moisture and temperature on the mechanical properties of additive manufacturing components: fused deposition modeling

2016 ◽  
Vol 22 (6) ◽  
pp. 887-894 ◽  
Author(s):  
Eunseob Kim ◽  
Yong-Jun Shin ◽  
Sung-Hoon Ahn
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Water Absorption ◽  
Fused Deposition Modeling ◽  
Content Type ◽  
Fused Deposition ◽  
Temperature Conditions ◽  
Molded Parts ◽  
Deposition Modeling ◽  
Injection Molded

Purpose This paper aims to investigate the water absorption behaviors and mechanical properties, according to water absorption and temperature, of components fabricated by fused deposition modeling (FDM) and injection molding. The mechanical properties of FDM and injection molded parts were studied under several environmental conditions. Design/methodology/approach FDM components can be used as load-carrying elements under a range of moisture and temperature conditions. FDM parts show anisotropic mechanical properties according to build orientation. Components were fabricated from acrylonitrile-butadiene-styrene in three different orientations. The mechanical properties of parts fabricated by FDM were compared to injection molded components made from the same material. Water absorption tests were conducted in distilled water between 20 and 60°C to identify the maximum water absorption rate. Both moisture and temperature were considered as environmental variables in the tensile tests, which were conducted under various conditions to measure the effects on mechanical properties. Findings The water absorption behavior of FDM components obeyed Fickian diffusion theory, irrespective of the temperature. High temperatures accelerated the diffusion rate, although the maximum water absorption rate was not affected. The tensile strength of FDM parts under dry, room temperature conditions, was approximately 26-56 per cent that of injection molded parts, depending on build orientation. Increased temperature and water absorption had a more significant effect on FDM parts than injection molded components. The tensile strength was decreased by 67-71 per cent in hot, wet environments compared with dry, room temperature conditions. Originality/value The water absorption behavior of FDM components was investigated. The quantitative effects of temperature and moisture on tensile strength, modulus and strain were also measured. These results will contribute to the design of FDM parts for use under various environmental conditions.

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 Parameters on Properties of Insert-Injection Molded Polypropylene Single-Polymer Composites

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 23
Author(s):  
Jian Wang ◽  
Qianchao Mao ◽  
Nannan Jiang ◽  
Jinnan Chen
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Injection Pressure ◽  
Holding Time ◽  
Injection Molding Process ◽  
Processing Temperature ◽  
Molding Process ◽  
Multiple Production ◽  
Injection Speed ◽  
Injection Molded

The reinforcement and matrix of a polymer material can be composited into a single polymer composite (SPC), which is light weight, high strength, and has easy recyclability. The insert injection molding process can be used to realize the multiple production of SPC products with a short cycle time and wide processing temperature window. However, injection molding is a very complicated process; the influence of several important parameters should be determined to help in the future tailoring of SPCs to specific applications. The effects of varying barrel temperature, injection pressure, injection speed, and holding time on the properties of the insert-injection molded polypropylene (PP) SPC parts were investigated. It was found that the sample weight and tensile properties of the PP SPCs varied in different rules with the variations of these four parameters. The barrel temperature has a significant effect, followed by the holding time and injection pressure. Suitable parameter values should be determined for enhanced mechanical properties. Based on the tensile strength, a barrel temperature of 260 °C, an injection pressure of 127.6 MPa, an injection speed of 0.18 m/s, and a holding time of 60 s were determined as the optimum processing conditions. The best tensile strength and peel strength were up to 120 MPa and 19.44 N/cm, respectively.

scholarly journals Mechanical Properties of Polypropylene (PP) – Montmorillonite (MMT) Nanocomposites for Pre-Fabricated Vertical Drain (PVD) Application

2018 ◽  
Vol 7 (4.35) ◽  
pp. 689
Author(s):  
N.A. Selamat ◽  
M.N. M.Ansari ◽  
Zainudin Yahya ◽  
Ragunatha E.Naicker
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Tensile Modulus ◽  
Injection Pressure ◽  
Optimum Process ◽  
Melt Mixing ◽  
Melt Temperature ◽  
Injection Speed ◽  
Molding Method ◽  
Vertical Drain

Polypropylene (PP) – montmorillonite (MMT) blends were prepared by melt-mixing method followed by injection molding method. The optimum process melt-temperature was set at 1950C, the injection speed of 15cc/s, injection pressure of 30MPa and cooling time of 20 sec. was used for the sample preparation. Investigation shows, addition of MMT nanoparticles have improved the mechanical properties. The tensile test and impact test were conducted at room temperature and atmospheric pressure. The tensile modulus and yield strength improved with increasing MMT content, however, elongation at break was reduced as the MMT content was increased from 2wt% to 8wt%. The Izod impact strength is also affected by the addition of MMT content. Nanocomposites based on PP containing 8wt% of MMT showed higher impact strength than the other compositions and Neat PP (control). The influence of MMT content on impact strength increased with MMT content which is a significant result required for pre-fabricated vertical drain (PVD). Further investigations are required to study the mechanical properties of the PVD using PP – MMT nanocomposites to replace the existing material (PP).

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.

Semisolid Die-Casting Process of Mg-20Al-0.8Zn Magnesium Alloy

2011 ◽  
Vol 306-307 ◽  
pp. 539-543
Author(s):  
Feng Yun Yan ◽  
Xiao Feng Huang ◽  
Bo Li ◽  
Ying Ma
Keyword(s):  
Tensile Strength ◽  
Die Casting ◽  
Injection Pressure ◽  
Casting Process ◽  
Elongation Rate ◽  
Isothermal Heat Treatment ◽  
Technological Parameters ◽  
Injection Speed ◽  
Die Casting Process ◽  
Spherical Grains

Based on microstructure evolution of Mg-20Al-0.8Zn magnesium alloys realized by semisolid isothermal heat-treatment (SSIT), we obtained the non-dendrite or spherical grains microstructure under the suitable technological parameters that isothermal temperature is 495 °C and holding time is 120 min. With the help of special experimental equipment, the semisolid die-casting process has been studied and the specimens have been analyzed. The effects of different parameters as injection speed and pressure on tensile strength, elongation rate, hardness, etc have been investigated. The results indicate that tensile strength was improved along with increasing injection speed and pressure. However, excessive speed will involve gas, which formed defects and reduced the mechanical properties. When the injection pressure is 40MPa and injection speed is 4m/s, the tensile strength and elongation rate can reach maximal 220MPa and 5.63% respectively. Its fracture mechanism was intercrystalline cracking.

scholarly journals The effect of foaming agent on mechanical and physical properties of Polypropylene

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
SEDEF CAKIR 1 ◽  
MUHAMMED AYCICEK 1 ◽  
EDIZ ALTUN 2 ◽  
Akin Akinci 1
Keyword(s):  
Mechanical Properties ◽  
Cell Density ◽  
Cell Morphology ◽  
Injection Pressure ◽  
Skin Layer ◽  
Polymer Materials ◽  
Cell Diameter ◽  
Melt Temperature ◽  
Foaming Agent ◽  
Foaming Agents

In this study, Polypropylene (PP) foam materials were used with injection parameters such as melting, molding and injection temperatures. To produce foam materials, chemical foaming agents were used, and added to polymer materials as 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%. The mechanical properties of foam samples were determined based on the parameters. Cell morphology characterization such as cell diameter, cell count, skin layer thickness and cell density, and mechanical properties such as tensile and impact strength of polymer foams were examined.Generally, the closed-cell foam structure was obtained. The most important parameters affecting the cell morphology have been injection pressure, melt temperature and amount of foaming agent. With increasing the amount of foaming agent, cell density increased, foam density and mechanical properties decreased.

Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 294-299 ◽  
Author(s):  
Zhi Bian ◽  
Peng Cheng Xie ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Process Conditions ◽  
Fiber Reinforced ◽  
Injection Speed ◽  
Glass Fiber Reinforced ◽  
Microcellular Injection Molding ◽  
Molded Parts

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically significant main and two-factor interaction effects, the results showed that the supercritical fluid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.

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