scholarly journals Experimental and Numerical Investigation of the Effect of Process Conditions on Residual Wall Thickness and Cooling and Surface Characteristics of Water-Assisted Injection Molded Hollow Products

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hyungpil Park ◽  
Baeg-Soon Cha ◽  
Byungohk Rhee
Keyword(s):  
Injection Molding ◽  
Wall Thickness ◽  
Automobile Industry ◽  
Three Dimensional ◽  
Surface Characteristics ◽  
Process Conditions ◽  
Melt Temperature ◽  
Hollow Section ◽  
Injection Process ◽  
Tube Type

Recently, water-assisted injection molding was employed in the automobile industry to manufacture three-dimensional hollow tube-type products with functionalities. However, process optimization is difficult in the case of water-assisted injection molding because of the various rheological interactions between the injected water and the polymer. In this study, the boiling phenomenon that occurs because of the high melt temperature when injecting water and the molding characteristics of the hollow section during the water-assisted injection process were analyzed by a water-assisted injection molding analysis. In addition, the changes in the residual wall thickness accompanying changes in the process conditions were compared with the analysis results by considering water-assisted injection molding based on gas-assisted injection molding. Furthermore, by comparing the cooling characteristics and inner wall surface qualities corresponding to the formation of the hollow section by gas and water injections, a water-assisted injection molding technique was proposed for manufacturing hollow products with functionality.

Optimization of Process Parameters for Injection Molding Based on Taguchi Technique

2012 ◽  
Vol 538-541 ◽  
pp. 1170-1174
Author(s):  
Shi Jun Fu
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Orthogonal Design ◽  
Mold Temperature ◽  
Optimum Process ◽  
Process Conditions ◽  
Injection Time ◽  
Melt Temperature ◽  
Injection Process ◽  
Packing Pressure

In this paper, Taguchi and CAE technique are combined to study the influence of process conditions on the warpage of injection molding parts through twice orthogonal design experiments, and the injection process parameters are optimized according to the warpage. For the parameters selected, melt temperature and packing pressure have effects on the warpage of injection molding parts are highly significant, injection time is significant, other parameters have little effects. Within the range of experiments, the warpage decreased with the rise of the melt temperature and packing pressure. At last, the optimum process parameters of injection are that the mold temperature is 60°C, packing time is 10s, melt temperature is240°C, packing pressure is 115MPa and injection time is 0.4s.

Reduction in Defect Rate by Taguchi Method in Plastic Injection Molded Components

2012 ◽  
Vol 488-489 ◽  
pp. 269-273 ◽  
Author(s):  
G.S. Dangayach ◽  
Deepak Kumar
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Processing Parameters ◽  
Process Conditions ◽  
Melt Temperature ◽  
Defect Rate ◽  
Packing Pressure ◽  
Optimal Injection ◽  
Packing Time ◽  
Plastic Injection

In the present era, competition gets tougher; there is more pressure on manufacturing sectors to improve quality and customer satisfaction while decreasing cost and increasing productivity. These can be achieved by using modern quality management systems and process improvement techniques to reduce the process variability and driven waste within manufacturing process using effective application of statistical tools. Taguchi technique is well known technique to solve industrial problems. This technique is fast and can pinpoint the chief causes and variations. Plastic injection molding is suitable for mass production articles since complex geometries can be obtained in a single production step. The difficulty in setting optimal process conditions may cause defects in parts, such as shrinkage and warpage. In this paper, optimal injection molding conditions for minimum shrinkage were determined by the Taguchi design of experiment (DOE) approach. Polypropylene (PP) was injected in circular shaped specimens under various processing parameters: melt temperature, injection pressure, packing pressure and packing time. S/N ratios were utilized for determining the optimal set of parameters. According to the results, 2400 C of melt temperature, 75 MPa of injection pressure, 50 MPa of packing pressure and 15 sec. of packing time gave minimum shrinkage of 0.951% for PP. Statically the most significant parameter was melt temperature for the PP. Injection pressure had the least effect on the shrinkage. The defect rate was reduced from 14% to 3%.

Effect of Injection Parameters on Warpage and Sink Index of High-Gloss Injection Parts

2014 ◽  
Vol 621 ◽  
pp. 88-93
Author(s):  
Yi Ning Song ◽  
Xi Ping Li ◽  
Ning Ning Gong
Keyword(s):  
Injection Molding ◽  
Mold Temperature ◽  
Rapid Cool ◽  
Orthogonal Experimental Design ◽  
Melt Temperature ◽  
Injection Process ◽  
Element Simulation ◽  
Injection Technology ◽  
Plastic Parts ◽  
Heat Injection

High-gloss injection molding technology is also called rapid cool and heat injection technology which can be used to eliminate weldmark on the surface of plastic parts, and improve the surface glossiness. However, the warpage, sink index and volume shrinkage of the parts are considered difficult to solve by using this technology. Reasons that cause the warpage and sink index of the parts were discussed in this paper firstly. Then, by using a LCD panel produced in practical injection process as an example, through orthogonal experimental design and finite element simulation, this paper discusses the effects of the injection molding parameters such as mold temperature, melt temperature etc. on warpage and sink index of the parts. The results are of great significance to help to set practical process parameters and assure the part quality in injection process.

scholarly journals A Study on the Void Formation in Residual Wall Thickness of Fluid-Assisted Injection Molding Parts

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hyung-Pil Park ◽  
Baeg-Soon Cha ◽  
Soo-Bin Park ◽  
Jae-Hyuk Choi ◽  
Dong-Han Kim ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Temperature Distribution ◽  
Injection Molding ◽  
Temperature Change ◽  
Wall Thickness ◽  
Silicone Oil ◽  
Void Formation ◽  
Heat Transfer Analysis ◽  
Hollow Section

In fluid-assisted injection molding, the distribution of the residual wall thickness on the inside and outside of the curved area is different, and void is formed due to the effect of the shrinkage on the outside where the residual wall thickness is thicker. The shrinkage that takes place in the residual wall is affected by the rheological changes in the polymer caused by temperature change and also by the thermal properties of the penetration fluid. In this study, the different effects on void formation in residual wall during fluid-assisted injection molding were analyzed, and water and silicone oil that had different thermal properties were used for the fluids. For this, heat transfer analysis and injection molding analysis were conducted. The void formation occurred due to the different temperature distribution and volumetric shrinkage in the direction of the residual wall in the curved area with a hollow section. It was also found that the void formation in the curved area decreased in the case of silicone oil compared to the case of water from simulation and experiments.

Influence of Process Conditions on the Local Shrinkage and on the Pressure Evolution inside the Mold Cavity of the Injection Molded Polypropylene in Two Modifications - PP Homopolymer; 40 % Talc Filled PP

2015 ◽  
Vol 669 ◽  
pp. 11-18
Author(s):  
Robert Záboj
Keyword(s):  
Rectangular Plate ◽  
Wall Thickness ◽  
Injection Rate ◽  
Semicrystalline Polymer ◽  
Mutual Interaction ◽  
Mold Cavity ◽  
Process Conditions ◽  
Melt Temperature ◽  
Injection Molded ◽  
Pressure Evolution

This work is focusing on optimization of the chosen process conditions (melt temperature, injection rate and holding pressure) and their mutual interaction on the local shrinkage of wall thickness carried out on rectangular plate. The test was applied on semicrystalline polymer in following modifications - polypropylene homopolymer and 40 % talc filled polypropylene. For better understanding of processes influencing shrinkage the pressure evolution inside cavity was captured by transducers placed near the gate and at the end of flow.

The Effect of Non-Return Nalve on Micro Injection Molding Machine

2013 ◽  
Vol 753-755 ◽  
pp. 1495-1498
Author(s):  
Rui Huan Huang ◽  
Gang Zhou ◽  
Li Qun Dong ◽  
Ya Jun Zhang
Keyword(s):  
Injection Molding ◽  
Pressure Difference ◽  
Pressure Field ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Molding Machine ◽  
Micro Injection Molding ◽  
Injection Molding Machine ◽  
Injection Process ◽  
Isothermal Fluid

The micro injection molding machine (MIMM) is used to produce precision plastic products. The non-return valve (NRV) on the screw head of injection machine plays the role of preventing the melt back discharge during injection process. The sensitivity of non-return valves opening and closing affects the quality of the product. In this paper, numerical simulation of three-dimensional flow field is generalized by the Newtonian isothermal fluid method. Then, five kinds of different structural parameters of NRV are designed, and the pressure field, the pressure difference is simulated by the Polyflow software. At last, the pressure field, and the pressure difference on both side of NRV are analyzed and compared. The best structure parameter of NRV is decided. The simulation results are useful for the NRV design.

scholarly journals Welding lines formation in holes obtained by low pressure injection molding of ceramic parts

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 97-103 ◽  
Author(s):  
C. A. Costa ◽  
A. F. Michels ◽  
M. E. Kipper
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Low Pressure ◽  
Process Conditions ◽  
Injection Mold ◽  
Extraction Temperature ◽  
Post Injection ◽  
Injection Process ◽  
Pressure Injection

Abstract This work presents a study to evaluate the process of producing internal holes in ceramic disks produced by low pressure injection molding (LPIM) process. Two process conditions defined as pre-injection and post-injection were used to test the proposition. In the first one the pin cores that produce the holes were positioned in the cavity before the injection of the feedstock; and in the second one, the pin cores were positioned in the cavity, just after the feeding phase of the injection mold. An experimental injection mold designed and manufactured to test both processes was developed to produce ceramic disk with Ø 50 x 2 mm with four holes of Ø 5 mm, equally and radially distributed through the disk. The feedstock was composed of 86 wt% alumina (Al2O3) and 14 wt% organic vehicle based on paraffin wax. Heating and cooling systems controlled by a data acquisition system were included in the mold. The results showed that there were no welding lines with the post-injection process, proving to be an option for creating holes in the ceramic parts produced by LPIM. It was observed that best results were obtained at 58 °C mold temperature. The pins extraction temperature was about 45 °C, and the injection pressure was 170 kPa.

scholarly journals Study of Residual Wall Thickness and Multiobjective Optimization for Process Parameters of Water-Assisted Injection Molding

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jiangen Yang ◽  
Shengrui Yu ◽  
Ming Yu
Keyword(s):  
Neural Network ◽  
Injection Molding ◽  
Multiobjective Optimization ◽  
Process Parameters ◽  
Wall Thickness ◽  
Rbf Neural Network ◽  
Water Pressure ◽  
Pareto Frontier ◽  
Melt Temperature ◽  
Important Indicator

Residual wall thickness is an important indicator for water-assisted injection molding (WAIM) parts, especially the maximization of hollowed core ratio and minimization of wall thickness difference which are significant optimization objectives. Residual wall thickness was calculated by the computational fluid dynamics (CFD) method. The response surface methodology (RSM) model, radial basis function (RBF) neural network, and Kriging model were employed to map the relationship between process parameters and hollowed core ratio, and wall thickness difference. Based on the comparison assessments of the three surrogate models, multiobjective optimization of hollowed core ratio and wall thickness difference for cooling water pipe by integrating design of experiment (DOE) of optimized Latin hypercubes (Opt LHS), RBF neural network, and particle swarm optimization (PSO) algorithm was studied. The research results showed that short shot size, water pressure, and melt temperature were the most important process parameters affecting hollowed core ratio, while the effects of delay time and mold temperature were little. By the confirmation experiments for the best solution resulted from the Pareto frontier, the relative errors of hollowed core ratio and wall thickness are 2.2% and 3.0%, respectively. It demonstrated that the proposed hybrid optimization methodology could increase hollowed core ratio and decrease wall thickness difference during the WAIM process.

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).

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.

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