scholarly journals The Microcellular Structure of Injection Molded Thick-Walled Parts as Observed by In-Line Monitoring

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5464
Author(s):  
Dariusz Sykutera ◽  
Piotr Czyżewski ◽  
Piotr Szewczykowski
Keyword(s):  
Rheological Properties ◽  
Flow Direction ◽  
Nitrogen Pressure ◽  
Mold Cavity ◽  
Sem Images ◽  
Temperature Changes ◽  
Injection Process ◽  
Microcellular Injection Molding ◽  
Ct Analysis ◽  
Line Pressure

The aim of the study was to detect the influence of nitrogen pressure on the rheological properties and structure of PA66 GF30 thick-walled parts, produced by means of microcellular injection molding (MIM), using the MuCell® technology. The process was monitored in-line with pressure and temperature sensors assembled in the original injection mold. The measured data was subsequently used to evaluate rheological properties inside an 8.4 mm depth mold cavity. The analysis of the microcellular structure was related to the monitored in-line pressure and temperature changes during the injection process cycle. A four-times reduction of the maximum filling pressure in the mold cavity for MIM was found. At the same time, the holding pressure was taken over by expanding cells. The gradient effect of the cells distribution and the fiber arrangement in the flow direction were observed. A slight influence of nitrogen pressure on the cells size was found. Cells with a diameter lower than 20 µm dominate in the analyzed cases. An effect of reduction of the average cells size in the function of distance to the gate was observed. The creation of structure gradient and changes of cells dimensions were evaluated by SEM images and confirmed with the micro CT analysis.

scholarly journals High-Performance of a Thick-Walled Polyamide Composite Produced by Microcellular Injection Molding

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4199
Author(s):  
Dariusz Sykutera ◽  
Piotr Czyżewski ◽  
Piotr Szewczykowski
Keyword(s):  
Injection Molding ◽  
High Performance ◽  
Flow Direction ◽  
Cell Diameter ◽  
Injection Molding Process ◽  
Polyamide 66 ◽  
Molding Process ◽  
Sem Images ◽  
Microcellular Injection Molding ◽  
Sink Mark

Lightweight moldings obtained by microcellular injection molding (MIM) are of great significance for saving materials and reducing energy consumption. For thick-walled parts, the standard injection molding process brings some defects, including a sink mark, warpage, and high shrinkage. Polyamide 66 (PA66)/glass fiber (GF) thick-walled moldings were prepared by MuCell® technology. The influences of moldings thickness (6 and 8.4 mm) and applied nitrogen pressure (16 and 20 MPa) on the morphology and mechanical properties were studied. Finally, the microcellular structure with a small cell diameter of about 30 μm was confirmed. Despite a significant time reduction of the holding phase (to 0.3 s), high-performance PA66 GF30 foamed moldings without sink marks and warpage were obtained. The excellent strength properties and favorable impact resistance while reducing the weight of thick-walled moldings were achieved. The main reason for the good results of polyamide composite was the orientation of the fibers in the flow direction and the large number of small nitrogen cells in the core and transition zone. The structure gradient was analysed and confirmed with scanning electron microscopy (SEM) images, X-ray micro computed tomography (micro CT) and finite element method (FEM) simulation.

Colloidal characteristics of gelatin-treated clay: Intercalation, stability, wettability, and rheological properties

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1361-S1370
Author(s):  
Xuwu Luo ◽  
Guancheng Jiang ◽  
Xinliang Li ◽  
Lili Yang
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Rheological Properties ◽  
Water Contact Angle ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Water Contact ◽  
Ζ Potential ◽  
And Behavior ◽  
Clay Intercalation

In this paper, sodium montmorillonite was modified with gelatin of different concentrations, and various colloidal characteristics of the gelatin-treated clays were measured and analyzed in detail. First, the influence of gelatin on the interlayer space of Mt layers was investigated by X-ray diffraction analysis. Moreover, the aggregation of Mt particles was examined using a combination of electron microscopy and particle size distribution experiments, while the variation of the electrical property of Mt was measured using ζ potential test. Gelatin of different concentrations can increase the particle size of Mt in different degrees. The addition of 4% gelatin could improve the ζ potential of Mt from −30.65 to −15.55 mV. The wettability change of modified Mt induced by the adsorption of gelatin was followed by measurements of water contact angle and observations of the morphology of Mt/gelatin membrane through SEM images. 4% gelatin could improve the water contact angle of Mt to 81.3°. Finally, the rheological properties of Mt/gelatin dispersion including shear viscosity and shear stress were measured using a stress-controlled rheometer. All of the results were consistent by showing that the overall colloidal characteristics and behavior of the gelatin-treated Mt strongly varied depending on the gelatin concentration used in the modification process. These results can provide a deep and comprehensive understanding of the colloidal properties of clay/gelatin systems and give important guidance for the performance design and improvement of Mt/gelatin composite materials. Furthermore, this study can also be expanded the application of gelatin and its composites to other fields.

scholarly journals Bio-Based Thermoplastic Starch Composites Reinforced by Dialdehyde Lignocellulose

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3236
Author(s):  
Peng Yin ◽  
Wen Zhou ◽  
Xin Zhang ◽  
Bin Guo ◽  
Panxin Li
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Water Resistance ◽  
Thermoplastic Starch ◽  
Contact Angles ◽  
Sem Images ◽  
Elongation At Break ◽  
Injection Process ◽  
Oxidation Damage

In order to improve the mechanical properties and water resistance of thermoplastic starch (TPS), a novel reinforcement of dialdehyde lignocellulose (DLC) was prepared via the oxidation of lignocellulose (LC) using sodium periodate. Then, the DLC-reinforced TPS composites were prepared by an extrusion and injection process using glycerol as a plasticizer. The DLC and LC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the effects of DLC content on the properties of the DLC/TPS composites were investigated via the evaluation of SEM images, mechanical properties, thermal stability, and contact angles. XRD showed that the crystallinity of the DLC decreased due to oxidation damage to the LC. SEM showed good dispersion of the DLC in the continuous TPS phase at low amounts of DLC, which related to good mechanical properties. The tensile strength of the DLC/TPS composite reached a maximum at a DLC content of 3 wt.%, while the elongation at break of the DLC/TPS composites increased with increasing DLC content. The DLC/TPS composites had better thermal stability than the neat TPS. As the DLC content increased, the water resistance first increased, then decreased. The highest tensile strength and elongation at break reached 5.26 MPa and 111.25%, respectively, and the highest contact angle was about 90.7°.

Coated Composite Crosstie Mold Structure Design Used for Experiment with Inventor, Moldflow and Ansys

2013 ◽  
Vol 561 ◽  
pp. 196-200
Author(s):  
Yu Guang Gong ◽  
Zhi Wen Zong ◽  
Ying Yu ◽  
Bai Yuan Lv
Keyword(s):  
Simulation Analysis ◽  
Displacement Vector ◽  
Processing Parameters ◽  
Structure Design ◽  
Mold Cavity ◽  
Von Mises Stress ◽  
Process Conditions ◽  
Injection Mold ◽  
Injection Process ◽  
Von Mises

Coated crosstie products and counter mold components are created in 3-D model using Inventor software, preparing for CAE analysis. By using Moldflow software , to determine products gate location, filling, packing, cooling, push-out processing, as well as the injection process conditions optimization of simulation analysis to find possible defects, modify and optimize the design, determine the best processing parameters and conditions. Binding using Ansys11.0 software to analyze rail sleeper mold cavity deformation, structure stress, get distribution of property of von Mises stress and displacement vector sum, in the mold cavity on the contact surface. By changing the cavity wall thickness, and other factors to improve the force which it is subjected, providing references to structure optimization of injection mold design. It has been proven that in collaborative application of these three softwares, the design of the injection mold is a very efficient and easy.

scholarly journals Study on MHD Cylindrical Couette Flow and Rheological Properties of Some Magnetic Suspensions

2019 ◽  
Vol 16 (1) ◽  
pp. 119-140
Author(s):  
S.E. E. Hamza
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Magnetic Force ◽  
Flow Direction ◽  
Practical Importance ◽  
Magnetic Field Effects ◽  
Shear Rates ◽  
Concentric Cylinders ◽  
Cylindrical Couette Flow ◽  
Water Glycerol

The study of magnetic suspensions (MS) and magnetic field effects on their rheological properties is of evident practical importance due to its ability to orient and change their physical properties, especially their viscosity, by magnetic fields. This research presents the effect of a uniform magnetic field on the flow of MS in the annular region between two concentric cylinders. The motion of the fluid is due to the rotation of the inner cylinder with a constant angular velocity. An exact solution of the governing equations is obtained in the form of modified Bessel functions of the first and second kinds. The torque, which must be applied to the inner cylinder in order to maintain the rotation, is also calculated. The results show that as the magnetic parameter increases, the velocity profile decreases, while the torque increases due to the effect of magnetic force against the flow direction. In order to model the magnetoviscous effects, experiments were performed for different shear rates and different magnetic field strengths by using specially designed rheometers. The studied samples are iron oxide-water-glycerol system,  ferrofluid nanoparticles, MAG DX biocompatible ferrofluid. The theoretical analysis is based on Giesekus model for MS. This model gives more accurate results and takes into account the effects of viscoelastic shear thinning characteristics. It is found that a magnetic field increases the viscosity of all suspensions under consideration. Finally, new proposed correlation for the viscosity of MS as a function of both shear rate and magnetic field has been suggested.

Rheological Characteristics of Surfactant-Based Fluids: A Comprehensive Study

2018 ◽  
Author(s):  
Ahmed H. Kamel
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Surfactant Concentration ◽  
Flow Direction ◽  
Shear Thinning ◽  
Molecular Structures ◽  
Wide Range ◽  
Unique Nature ◽  
Viscoelastic Surfactant

Surfactant-based fluids, SB fluids exhibit complex rheological behavior due to substantial structural change caused by the molecules self-assembled colloidal aggregation. Various factors affect their rheological properties. Among these factors, surfactant concentration, shear rate, temperature, and salinity are investigated. One of the most popular surfactants, Aromox® APA-T viscoelastic surfactant (VES) is examined. The study focuses on four different concentrations (1.5%, 2%, 3%, and 4%) over a shear rate ranging from 0.0526 sec−1 to 1944 sec−1 using Bohlin rheometer. For salinity effects, two brine solutions are used; 2 and 4% KCl while for temperature effects, a wide range from ambient temperature of 72°F up to 200°F is covered. The results show that SB fluids exhibit a complex rheological behavior due to its unique nature and the various structures form in the solution. In general, SB fluids at all concentrations exhibit a non-Newtonian pseudo-plastic shear thinning behavior. As the surfactant concentration and/or shear increases, a stronger shear thinning behavior can be seen. Increasing solution salinity promotes formation of rod-like micelles and increases its flexibility. Salinity affects micelles’ growth and their rheological behavior is very sensitive to the nature and structure of the added salt. Different molecular structures are formed; spherical micelles occur first and then increased shear rate and/or salinity promotes the formation of rod-like micelles. Later, rod-like micelles are aligned in the flow direction and form a large super ordered structure of micellar bundles or aggregates called shear induced structure (SIS). Different structures implies different rheological properties. Likewise, rheology improves with increasing temperature up to 100°F. Further increase in temperature reverses the effects and viscosity decreases. However, the effects of temperature and salinity diminish at higher shear rates. Furthermore, a rheology master curve is developed to further understand the rheological behavior of SB fluids and correlate rheological properties to its microscopic structure.

scholarly journals Analysis of the Influence of Microcellular Injection Molding on the Environmental Impact of an Industrial Component

2014 ◽  
Vol 6 ◽  
pp. 793269 ◽  
Author(s):  
Daniel Elduque ◽  
Isabel Clavería ◽  
Ángel Fernández ◽  
Carlos Javierre ◽  
Carmelo Pina ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Environmental Impact ◽  
Injection Molding ◽  
Flexural Modulus ◽  
Green Manufacturing ◽  
Flexural Properties ◽  
Special Device ◽  
Injection Process ◽  
Microcellular Injection Molding ◽  
Green Manufacturing Technology

Microcellular injection molding is a process that offers numerous benefits due to the internal structure generated; thus, many applications are currently being developed in different fields, especially home appliances. In spite of the advantages, when changing the manufacturing process from conventional to microcellular injection molding, it is necessary to analyze its new mechanical properties and the environmental impact of the component. This paper presents a deep study of the environmental behavior of a manufactured component by both conventional and microcellular injection molding. Environmental impact will be evaluated performing a life cycle assessment. Functionality of the component will be also evaluated with samples obtained from manufactured components, to make sure that the mechanical requirements are fulfilled when using microcellular injection molding. For this purpose a special device has been developed to measure the flexural modulus. With a 16% weight reduction, the variation of flexural properties in the microcellular injected components is only 6.8%. Although the energy consumption of the microcellular injection process slightly increases, there is an overall reduction of the environmental burden of 14.9% in ReCiPe and 15% in carbon footprint. Therefore, MuCell technology can be considered as a green manufacturing technology for components working mainly under flexural load.

Numerical Investigation on the Effect of Injection Pressure on Melt Front Pressure and Velocity Drop

2015 ◽  
Vol 786 ◽  
pp. 210-214
Author(s):  
M.S. Rusdi ◽  
Mohd Zulkifly Abdullah ◽  
A.S. Mahmud ◽  
C.Y. Khor ◽  
M.S. Abdul Aziz ◽  
...  
Keyword(s):  
Injection Molding ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Injection Pressure ◽  
Simulation Software ◽  
Mold Cavity ◽  
Injection Molding Process ◽  
Flow Profile ◽  
Molding Process ◽  
Injection Process

Computational Fluid Dynamic (CFD) was used to simulate the injection molding process of a tray. The study focuses on pressure distribution and velocity drop during the injection process. CFD simulation software ANSYS FLUENT 14 was utilized in this study. The melt front pressure in the mold cavity shows that it was affected by the shape of mold cavity and filling stage. The melt front pressure will decrease as the flow move further than the sprue but it will increase rapidly when the mold was about to be fully filled. The slight pressure drop was detected when the molten flow meets the rib of the tray. The velocity of higher injection pressure was greater than the lower injection pressure but the velocity rapidly dropped when the melt front fully filled the cavity. The current predicted flow profile was validated by the experimental results, which demonstrates the excellent capability of the simulation tool in solving injection-molding problems.

Self-Aligned Growth and Optimization of Carbon Nanotube

2011 ◽  
Vol 179-180 ◽  
pp. 316-319
Author(s):  
Ying Wu ◽  
Zhao Ying Zhou ◽  
Li Jun Sun ◽  
Jin Zhang ◽  
Xiao Yun Zhang
Keyword(s):  
Carbon Nanotube ◽  
Large Scale ◽  
Gas Flow ◽  
Flow Direction ◽  
Parallel Method ◽  
Sem Images ◽  
Sensing Systems ◽  
Aligned Growth ◽  
Large Scale Integration ◽  
Scale Integration

CNT-based integrated components show potential application in many fields. The growth of carbon nanotube is very important process for the fabrication of CNT-based component. Self-aligned growth of carbon nanotube method by gas-flowing techniques is reported in this paper, which results in CNT growth along gas-flow direction. The effect of gas-flow was analyzed with numerical simulation and the growth optimization was put forward. Scanning electronic microscopy (SEM) images demonstrate that the self-aligned carbon nanotube can be realized by a gas-flowing CVD process and the distribution of carbon nanotube can be controlled by the gas-flowing rates. This research provides a parallel method for the large-scale integration of carbon nanotube into electronic, optoelectronic, and sensing systems.

Effect of Molding Parameters on the Interface Morphology of Metal Co-Injection Molding

2011 ◽  
Vol 189-193 ◽  
pp. 2939-2944
Author(s):  
Hao He ◽  
Yi Min Li ◽  
Guang Yao Wang
Keyword(s):  
Rheological Properties ◽  
Delay Time ◽  
Flow Direction ◽  
Injection Velocity ◽  
Interface Morphology ◽  
Key Factors ◽  
The Core ◽  
Molded Parts ◽  
Injection Molded ◽  
Injection Temperature

In the present study, the effect of injection temperature, velocity and delay time on the interface morphology of the co-injection molded plates was studied. The results showed that the core penetration parallel to the flow direction becomes less as the skin injection velocity and temperature increases and delay time decreases. Among the parameters, temperature was the most significant in affecting the interface morphology, followed by delay time, while injection velocity seemed to play no significant role. The results were analyzed by taking account of rheological properties of the two feedstocks. Calculations and comparisons of viscosity ratios encountered in experiments were made. It was demonstrated the differences in the rheological properties of the metal feedstocks involved are key factors in determining the interface morphology of the molded parts.

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