Influence of the Mold Temperature and Part Thickness on the Replication Quality and Molecular Orientation in Compression Injection Molding of Polystyrene

2019 ◽  
Vol 34 (4) ◽  
pp. 425-433
Author(s):  
B. Roth ◽  
M.-Y. Zhou ◽  
D. Drummer
Keyword(s):  
Injection Molding ◽  
Molecular Orientation ◽  
Mold Temperature ◽  
Replication Quality ◽  
Part Thickness

Numerical Study on the Melt Flow Length of the Composite Materials in the Injection Molding Process

2019 ◽  
Vol 971 ◽  
pp. 15-20
Author(s):  
The Nhan Phan ◽  
Trung Do Thanh ◽  
Son Minh Pham
Keyword(s):  
Composite Materials ◽  
Injection Molding ◽  
Numerical Study ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Flow Length ◽  
Part Thickness ◽  
Good Agreement

Improving the melt flow length by increasing the mold temperature has been an issue encountered in the injection molding processes for composite products. In this study, an injection molding process was applied to a melt flow length model having a part thickness of 1.0 mm. The mold temperature varied from 30 °C to 110 °C. Six types of composite materials of polycaprolactam 6 (PA6) and glass fiber (GF) were selected to study the influence of mold temperature on the material filling in the injection molding process. The simulation results denoted that the mold temperature considerably influenced the flowability during the injection molding process, especially using 30% GF; further, the melt flow length was increased by 25.5% when the mold temperature was increased from 30 °C to 110 °C. In accordance with the simulation, our experiments demonstrated that we could achieve a mold temperature of 110 °C using all types of composite materials. Therefore, in this study, we denoted that both the simulation and experimental results of the melt flow length were comparable, thereby indicating a good agreement.

Effect of Micro-Injection Molding Processing Conditions on the Replication and Consistency of a Dense Network of High Aspect Ratio Microstructures

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
John W. Rodgers ◽  
Meghan E. Casey ◽  
Sabrina S. Jedlicka ◽  
John P. Coulter
Keyword(s):  
Injection Molding ◽  
Flow Rate ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Fluid Behavior ◽  
Replication Quality ◽  
Average Standard Error ◽  
Experimental Trials

When molding macroscale polymer parts with a high density of microfeatures (>1 × 106/cm2), a concern that presents itself is the ability to achieve uniform replication across the entire domain. In the given study, micro-injection molding was used to manufacture microfeatured polymer substrates containing over 10 × 106 microfeatures per cm2. Polystyrene (PS) plates containing microtopography were molded using different processing parameters to study the effect of flow rate and mold temperature on replication quality and uniformity. Flow rate was found to significantly affect replication at mold temperatures above the glass transition temperature (Tg) of PS while having no significant effect on filling at mold temperatures below Tg. Moreover, replication was dependent on distance from the main cavity entrance, with increased flow rate facilitating higher replication differentials and higher replication near the gate. Simulation of the molding process was used to corroborate experimental trials. A deeper understanding of polymer fluid behavior associated with micro-injection molding is vital to reliably manufacture parts containing consistent microtopography (Note: Values are expressed in average ± standard error).

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

Application of Taguchi Method for Parameters Optimization in Micro Metal Injection Molding

2011 ◽  
Vol 52-54 ◽  
pp. 244-248
Author(s):  
Haw Pei Li ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong ◽  
Heng Shye Yunn ◽  
Hooman Abolhasani
Keyword(s):  
Injection Molding ◽  
Signal To Noise Ratio ◽  
Steel Powder ◽  
Mold Temperature ◽  
Parameters Optimization ◽  
Simultaneous Optimization ◽  
Metal Injection Molding ◽  
Surface Appearance ◽  
Optimal Injection ◽  
Acetate Butyrate

Optimization of injection parameters in Micro Metal Injection Molding (μMIM) was described in this study. Stainless steel powder was mixed with Polyethelena Glycol (PEG), Polymethyl Methacrilate (PMMA) and Cellulose Acetate Butyrate (CAB) to produce feedstock. Design of Experiments (DOE) of Taguchi L-27 (313) orthogonal array technique has been used to investigate the significance and optimal injection molding parameters. The signal-to-noise ratio and analysis of variance (ANOVA) are applied to study the optimum levels and effects of process parameters. Simultaneous optimization to obtain the highest green density and excellent surface appearance was discussed. The result concluded that the mold temperature (D) is the most statistically significant process parameter and its contribution to the best appearance and density is the highest.

Study on Optical Properties of Microstructure of Lightguiding Plate for Micro Injection Molding and Micro Injection-Compression Molding

2006 ◽  
Vol 505-507 ◽  
pp. 229-234 ◽  
Author(s):  
Yung Kang Shen ◽  
H.J. Chang ◽  
C.T. Lin
Keyword(s):  
Optical Properties ◽  
Injection Molding ◽  
Digital Camera ◽  
Mold Temperature ◽  
Compression Molding ◽  
Micro Injection Molding ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Injection Compression Molding ◽  
Better Than

The purpose of this paper presents the optical properties of microstructure of lightguiding plate for micro injection molding (MIM) and micro injection-compression molding (MICM). The lightguiding plate is applied on LCD of two inch of digital camera. Its radius of microstructure is from 100μm to 300μm by linearity expansion. The material of lightguiding plate uses the PMMA plastic. This paper uses the luminance distribution to make a comparison between MIM and MICM for the optical properties of lightguiding plate. The important parameters of process for optical properties are the mold temperature, melt temperature and packing pressure in micro injection molding. The important parameters of process for optical properties are the compression distance, mold temperature and compression speed in micro injection-compression molding. The process of micro injection-compression molding is better than micro injection molding for optical properties.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

Three-Dimensional Simulation of Co-Injection Molding

2001 ◽  
Author(s):  
Florin Ilinca ◽  
Jean-François Hétu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Injection Molding ◽  
Three Dimensional ◽  
Mold Temperature ◽  
Dimensional Finite Element ◽  
Dimensional Simulation ◽  
Energy Equations ◽  
Three Dimensional Finite Element ◽  
Core Materials

Abstract This paper presents simulations of co-injection molding problems computed by a three-dimensional finite element method. The polymer melts behave as generalized Newtonian fluids and non-isothermal effects are taken into account. In addition to the momentum, mass and energy equations, we solve two transport equations tracking the polymer/air and skin/core polymers interfaces. Solutions are shown for a center gated rectangular plate. The effect of varying the melt/mold temperature and the ratio between the skin and core materials is investigated. The solution obtained for the same skin and core materials is compared with those in which viscosities of core and skin materials are different. Finally, the solution for the co-injection of a C-shaped plate is presented.

scholarly journals FTIR Analysis of Molecular Orientation at Weldline Region in Thermoplastics Injection Molding.

1992 ◽  
Vol 49 (7) ◽  
pp. 591-600 ◽  
Author(s):  
Kiyotaka TOMARI ◽  
Toshihiko HARADA ◽  
Zenichiro MAEKAWA ◽  
Hiroyuki HAMADA ◽  
Akio HAMAMOTO
Keyword(s):  
Injection Molding ◽  
Molecular Orientation ◽  
Ftir Analysis

scholarly journals Optimization of Process Parameters for Vertical-Faced Polypropylene Bottle Injection Molding

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Youmin Wang ◽  
Zhichao Yan ◽  
Xuejun Shan
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Dwell Time ◽  
Optimization Problem ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Orthogonal Test ◽  
Injection Molding Process ◽  
Injection Time ◽  
Melt Temperature

In order to obtain the optimal combination of process parameters for vertical-faced polypropylene bottle injection molding, with UG, the model of the bottle was drawn, and then, one module and sixteen-cavity injection molding system was established and analyzed using Moldflow. For filling and maintaining pressure during the process of infusion bottle injection molding, the orthogonal test table L25 (56) using CAE was designed for injection molding of the bottle, with six parameters such as melt temperature, mold temperature, injection pressure, injection time, dwell pressure, and dwell time as orthogonal test factors. By finding the best combination of process parameters, the orthogonal experiment was completed, the results were analyzed by range analysis, and the order of influence of each process parameter on each direction of optimization was obtained. The prediction dates of the infusion bottle were gained under various parameters, a comprehensive quality evaluation index of the bottle was formulated, and the multiobjective optimization problem of injection molding process was transformed into a single-objective optimization problem by the integrated weighted score method. The bottle parameters were optimized by analyzing the range date of the weighted scoring method, and the best parameter combination such as melt temperature 200°C, mold temperature 80°C, injection pressure 40 MPa, injection time 2.1 S, dwell pressure 40 MPa, and dwell time 40 S was gained.

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