The Experts below are selected from a list of 1464 Experts worldwide ranked by ideXlab platform

Fuping Chang - One of the best experts on this subject based on the ideXlab platform.

  • analysis of shrinkage and warpage in an Injection Molded Part with a thin shell feature using the response surface methodology
    The International Journal of Advanced Manufacturing Technology, 2007
    Co-Authors: Kota Chiang, Fuping Chang
    Abstract:

    This paper presents a systematic methodology to analyze the shrinkage and warpage in an Injection-Molded Part with a thin shell feature during the Injection molding process. The systematic experimental design based on the response surface methodology (RSM) is applied to identify the effects of machining parameters on the performance of shrinkage and warpage. The experiment plan adopts the centered central composite design (CCD). The quadratic model of RSM associated sequential approximation optimization (SAO) method is used to find the optimum value of machining parameters. One real case study in the Injection molding process of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) cell phone shell has been performed to verify the proposed optimum procedure. The mold temperature (M T), packing time (P t), packing pressure (P P) and cooling time (C t) in the packing stage are considered as machining parameters. The results of analysis of variance (ANOVA) and conducting confirmation experiments demonstrate that the quadratic models of the shrinkage and warpage are fairly well fitted with the experimental values. The individual influences of all machining parameters on the shrinkage and warpage have been analyzed and predicted by the obtained mathematical models. For the manufacture of PC/ABS cell phone shell, the values of shrinkage and warpage present the reduction of 37.8 and 53.9%, respectively, using this optimal procedure.

  • application of grey fuzzy logic on the optimal process design of an Injection Molded Part with a thin shell feature
    International Communications in Heat and Mass Transfer, 2006
    Co-Authors: Kota Chiang, Fuping Chang
    Abstract:

    This paper presents an effective approach for the optimization of machining parameters to an Injection-Molded Part with a thin shell feature (example of cell phone shell consist of PC/ABS material) based on the orthogonal array with the grey relational analysis and fuzzy logic analysis. Through the grey-fuzzy logic analysis, the optimization of complicated multiple performance characteristics can be converted into the optimization of a single grey-fuzzy reasoning grade. In this Injection molding process, the machining parameters, namely the mold temperature, melt temperature, filling pressure and filling time are optimized with considerations of multiple performance characteristics including the strength of welding line, the shrinkage and the difference of forming distributive temperature. The experimental results for the optimal setting have obviously shown that the above performance characteristics in the Injection molding process can be improved effectively together through this approach.

Mingchih Huang - One of the best experts on this subject based on the ideXlab platform.

  • the effective factors in the warpage problem of an Injection Molded Part with a thin shell feature
    Journal of Materials Processing Technology, 2001
    Co-Authors: Mingchih Huang
    Abstract:

    Abstract Communication and electronic products have been developing towards the design concept of being light, thin, short, and small. To acquire the maximal internal space for Parts to be packed closely into the product, one way is to reduce the wall thickness of the housing components. Therefore, the production technique of plastic Injection molding of a Part with a thin shell feature is becoming increasingly more important. Many factors lead to the defects of Parts, such as warpage, shrinkage, sink marks, residual stress, and so on. This research used the experimental design of Taguchi method to determine the Injection molding conditions, and the Injection processes were simulated using the commercial software C-MOLD™. Both molding conditions and factors were discussed regarding the degree of warpage of a thin shell Part. The results showed that the packing pressure had the greatest influence on the warpage, followed by mold temperature, melt temperature, and packing time. However, the warpage was only slightly influenced by the gate dimension and the filling time in thin shell Injection molding. In addition, applying the experimental design of Taguchi method is a quite effective method to deduce the optimum set of effective factors in Injection molding to produce plastic Parts with minimum warpage.

Kota Chiang - One of the best experts on this subject based on the ideXlab platform.

  • analysis of shrinkage and warpage in an Injection Molded Part with a thin shell feature using the response surface methodology
    The International Journal of Advanced Manufacturing Technology, 2007
    Co-Authors: Kota Chiang, Fuping Chang
    Abstract:

    This paper presents a systematic methodology to analyze the shrinkage and warpage in an Injection-Molded Part with a thin shell feature during the Injection molding process. The systematic experimental design based on the response surface methodology (RSM) is applied to identify the effects of machining parameters on the performance of shrinkage and warpage. The experiment plan adopts the centered central composite design (CCD). The quadratic model of RSM associated sequential approximation optimization (SAO) method is used to find the optimum value of machining parameters. One real case study in the Injection molding process of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) cell phone shell has been performed to verify the proposed optimum procedure. The mold temperature (M T), packing time (P t), packing pressure (P P) and cooling time (C t) in the packing stage are considered as machining parameters. The results of analysis of variance (ANOVA) and conducting confirmation experiments demonstrate that the quadratic models of the shrinkage and warpage are fairly well fitted with the experimental values. The individual influences of all machining parameters on the shrinkage and warpage have been analyzed and predicted by the obtained mathematical models. For the manufacture of PC/ABS cell phone shell, the values of shrinkage and warpage present the reduction of 37.8 and 53.9%, respectively, using this optimal procedure.

  • application of grey fuzzy logic on the optimal process design of an Injection Molded Part with a thin shell feature
    International Communications in Heat and Mass Transfer, 2006
    Co-Authors: Kota Chiang, Fuping Chang
    Abstract:

    This paper presents an effective approach for the optimization of machining parameters to an Injection-Molded Part with a thin shell feature (example of cell phone shell consist of PC/ABS material) based on the orthogonal array with the grey relational analysis and fuzzy logic analysis. Through the grey-fuzzy logic analysis, the optimization of complicated multiple performance characteristics can be converted into the optimization of a single grey-fuzzy reasoning grade. In this Injection molding process, the machining parameters, namely the mold temperature, melt temperature, filling pressure and filling time are optimized with considerations of multiple performance characteristics including the strength of welding line, the shrinkage and the difference of forming distributive temperature. The experimental results for the optimal setting have obviously shown that the above performance characteristics in the Injection molding process can be improved effectively together through this approach.

Changyu Shen - One of the best experts on this subject based on the ideXlab platform.

  • flow induced fiber orientation in gas assisted Injection Molded Part
    Materials Letters, 2007
    Co-Authors: Guoqiang Zheng, Wei Yang, Li Huang, Mingbo Yang, Wei Li, Changyu Shen
    Abstract:

    Polyamide 66 with 33 wt.% glass fiber (DuPont, Zytel 70G33) was Molded by gas-assisted Injection molding (GAIM). Scanning electron microscope (SEM) micrographs indicated that fibers orientated notably in the core layer and slightly in the region near the mold wall, but aligned disorderly in the region near the gas channel. However, fibers orientated remarkably in the center of the thickness of the GAIM Part, which was greatly different from the fiber orientation behavior in the samples Molded by the conventional Injection molding (CIM) and the water-assisted Injection molding (WAIM) as reported in the literatures. Combining with a previous simulation dealing with gas penetration, the mechanisms for fiber orientation in the GAIM Part are also discussed.

  • investigation of the effect of molding variables on sink marks of plastic Injection Molded Parts using taguchi doe technique
    Polymer-plastics Technology and Engineering, 2007
    Co-Authors: Changyu Shen, Lixia Wang, Li Qian
    Abstract:

    The quality of an Injection Molded Part is affected by material properties, mold geometry, process conditions etc. Obtaining optimum process conditions and mold design is the key problem to improve the Part quality. Sink mark is one of several important flaws of Injection Molded Parts. In this article, numerical simulation is combined with Taguchi design-of-experiment (DOE) technique to investigate the influence of process conditions and cavity geometry on sink mark of the Injection Molded Part and optimize process conditions and cavity geometry. An L18(37) orthogonal array based on the Taguchi method was conducted to minimize the sink marks of Injection Molded Parts, and the significance of each factors on sink mark was investigated. For the factors selected in the main experiments, Part thickness, holding pressure, melt temperature and mold temperature were found to be the principal factors affecting the sink marks of the Injection Molded Parts.

Shia-chung Chen - One of the best experts on this subject based on the ideXlab platform.

  • Effect of asymmetric cooling system on in-mold roller Injection Molded Part warpage☆
    International Communications in Heat and Mass Transfer, 2015
    Co-Authors: Hui Li Chen, Shia-chung Chen
    Abstract:

    Abstract In-mold decoration (IMD) Injection molding has been the most promising surface decoration technique in recent years, with the in-mold roller (IMR) Injection molding being the most automated production process. During the IMR process, heat transfer in the cavity surface is significantly retarded because of the low thermal conductivity of film. As a result of the asymmetric melt and mold temperature, thermal-induced Part warpage easily occurs. To understand the variation in the temperature field of the core and cavity caused by the plastic film, this research uses simulation and experiments to investigate the influence of the mold's (core-and-cavity) asymmetric cooling system temperature on product warpage, and examines the impact of the film's heat retardation effect on the crystallinity, tensile strength, and surface roughness of the treated products. Our results show that the film causes a higher contact temperature between the hot melt and mold during the molding process, resulting in asymmetric temperature in the mold (core and cavity), increasing the crystallinity of the cavity and consequently increasing product warpage. In plastic, the warpage increase is from 0.03 mm to 0.62 mm when the film thickness is 0.175 mm and the temperatures of the mold and hot melt are 50 °C and 230 °C, respectively, a great increase than with steel (P20). With the asymmetric cooling system design, in which the cavity temperature is 50 °C and the core temperature is 65 °C, the warpage can be reduced by 53%. For crystallinity and crystalline size, the film heat retardation effect of the IMR process increases the crystallinity of the cavity by 16%, and the crystallite size by 12%, along with some increase in tensile strength. In addition, the IMR process can also increase the smoothness of the product surface, reducing the surface roughness by 50%.

  • the application of fuzzy theory for the control of weld line positions in Injection Molded Part
    Isa Transactions, 2008
    Co-Authors: Mei-yung Chen, Huan Wen Tzeng, Yicheng Chen, Shia-chung Chen
    Abstract:

    Abstract This research proposes the fuzzy theory for the control of weld lines in plastic Injection molding. The weld line occurs as a result of geometrical changes in Molded Parts in the Injection molding process. The weld line is one of the defects present in plastic Injection-Molded Parts; the line affects the quality of Parts as well as the strength of the products. In the present study, fuzzy theory was applied in the design of Injection molding. First, expert experiences were transformed into I F ∼ T H E N ∼ rules to establish the knowledge base for developing fuzzy inference rules. The rules were then used to adjust the molding parameters, which in turn were applied to control the weld line position in the Injection molding process. The results indicate that fuzzy theory exhibited favorable applicability in the control of the weld line as well as decreased the simulation time, thereby accelerating the design process of Injection molding.