Дисертації з теми "Water assisted injection molding"
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1
Zerguine, Walid. "Adaptation de maillages anisotropes et écoulements multifluides : Applications en injection assistée eau." Paris, ENMP, 2010. http://www.theses.fr/2010ENMP0082.
Анотація:
L’Injection Assistée Eau (IAE) est un procédé récent de fabrications de pièces creuses thermoplastiques. La simulation numérique est une étape importante du processus de mise au point de cette technologie innovante. Le cadre de ces travaux de thèse est le développement d’un module de simulation numérique du procédé IAE. Les retombées industrielles et technologiques de cet outil numérique apporteront des informations cruciales sur la sensibilité des propriétés des pièces injectées aux conditions d’injection. L’hydrodynamique du système multiphasique polymère-eau-air est décrite par la résolution des équations de Navier-Stokes dans le cadre d’une formulation monolithique eulérienne. La méthode consiste à résoudre le système d’équations sur un seul maillage. Une fonction distance permet de décrire les interfaces eau-polymère et polymère-air, et de fournir les propriétés physiques de chaque sous-domaine. Une stratégie innovante d’adaptation dynamique de maillage anisotrope permet de diminuer les fortes hétérogénéités des phases en présence. Deux voies sont explorées. La première considère des maillages définis à partir de métriques construites a priori sur le gradient de la fonction Level set et la seconde approche considère la construction d’une métrique basée sur un estimateur d’erreur a posteriori minimisant l’erreur d’approximation sous contrainte de garder un nombre d’éléments constant. Une confrontation à des essais expérimentaux valide la pertinence de notre outil à prédire de manière précise l’évolution de la veine d’eau dans la pièce type IAEThe Water Assisted Injection Molding (WAIM) is a recent manufacturing process that produces thermoplastic hollow parts. Numerical simulation is an important step in the development of this innovative technology. The framework of the thesis is the development of a numerical simulation module for the WAIM process. The industrial and technological benefits of this numerical tool will provide crucial information on the sensitivity of the properties of injection molded parts to injection conditions. The hydrodynamics of the multiphase polymer-water-air system is described by the resolution of the Navier-Stokes equations within the framework of an eulerian monolithic formulation. The method consists in solving the system of equations on a single mesh. A distance function allows to describe the interfaces water-polymer and polymer-air to supply the physical properties of every sub-domain. A strategy of anisotropic dynamic mesh adaptation allows to decrease the strong heterogeneities of the phases in presence. Two ways are investigated. The first one considers meshes constructed from a priori metrics based on the gradient of the Levelset function and the second approach considers the construction of a metric based on a posteriori error estimator minimizing the error of approximation under constraint to keep a constant number of elements. A confrontation in experimental trials confirms the relevance of our tool to predict the evolution of the water vein in a typical WAIM part
2
Wang, Yijie. "The Effect Of Non-Newtonian Rheology On Gas-Assisted Injection Molding Process." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1053622915.
3
Carrillo, Antonio J. "Residual Stresses and Birefringence in Gas-assisted Injection Molding of Amorphous Polymers: Simulation and Experiment." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1214313599.
4
Zheng, Tianmin. "An investigation of gas-assisted injection molding : effects of process variables on gas bubble formation /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487861396026928.
5
Xu, Liqun. "Integrated analysis of liquid composite molding (LCM) processes." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1095688597.
Анотація:
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xix, 245 p.; also includes graphics. Includes bibliographical references (p. 233-245).
6
Polynkin, A., L. Bai, J. F. T. Pittman, J. Sienz, Leigh Mulvaney-Johnson, Elaine C. Brown, A. Dawson, et al. "Water assisted injection moulding: development of insights and predictive capabilities through experiments on instrumented process in parallel with computer simulations." Maney Publishing, 2008. http://hdl.handle.net/10454/3511.
Анотація:
YesAn idealised model of core-out in water assisted injection moulding (WAIM) is set up to isolate the effect of cooling by the water on the deposited layer thickness. Based on simulations, this is investigated for a specific case as a function of Pearson number and power law index. It is found that cooling significantly reduces the layer thickness to the extent that a change in the flow regime ahead of the bubble, from bypass to recirculating flow, is possible. For shear thinning melts with high temperature coefficient of viscosity, the simulations show very low layer thickness, which may indicate unfavourable conditions for WAIM. Although in the real moulding situation, other effects will be superimposed on those found here, the results provide new insights into the fundamentals of WAIM. Investigation of other effects characterised by Fourier and Reynolds numbers will be reported subsequently. Some early process measurement results from an experimental WAIM mould are presented. Reductions in residual wall thickness are observed as the water injection set pressure is increased and the duration of water bubble penetration through the melt is determined experimentally. The formation of voids within the residual wall is noted and observed to reduce in severity with increasing water injection pressure. The presence of such voids can be detected by the signature from an infrared temperatures sensor.
7
SHIH, Chang-Chih, and 史長志. "Water Assisted Injection Molding of Nylon 6." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/10315795030588143752.
Анотація:
碩士長庚大學
機械工程研究所
93
This report was to experimentally study the water assisted injection molding of glass fiber reinforced polyamide-6 (Nylon-6) composites. Experiments were carried out on an 80-ton injection-molding machine equipped with a lab scale water injection system, which included a water pump, a water injection pin, a water tank equipped with a temperature regulator, and a control circuit. The materials used were nylon and 30% glass fiber filled nylon composites. A spiral mold cavity was used to mold the composites. After molding, the lengths of water penetration in molded parts were measured. The effects of different processing parameters on the lengths of water penetration were determined: melt temperature, mold temperature, melt filling speed, short-shot size, water pressure, water temperature, water hold and water injection delay time. Mechanical property tests were performed on the water assisted injection molded parts. XRD has also been employed to identify the structural parameters of the materials. In addition, the in-mold temperature distribution of the polymeric materials during the cooling process was measured. Irregular water penetration in molded parts was observed. Water temperature was found to affect the crystallinity distribution of molded parts. Nevertheless, its effects on the tensile properties of molded materials were relatively limited.
8
Pan, Zhong ming, and 潘忠明. "The Study of Water-Assisted Injection Molding Process." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/50511316910339467405.
Анотація:
碩士清雲科技大學
機械工程研究所
94
This study investigated the manufacture of a handle bar by the water-assisted injection molding (WAIM) process. WAIM is a new technology based on gas-assisted injection molding (GAIM). Both use fluid as the medium, but one uses water while the other uses nitrogen gas. Experimental studies were conducted to determine the effects of process parameters on the hollowed core ratio and penetration length of the WAIM. Process parameters include melt temperature, water pressure, mold temperature, water injection delay time, shot size, and water temperature. Semi-crystalline material, PP, amorphous material, ABS, PP+GF, and ABS+GF were used for this study. Both single parameter method and Taguchi method were used to conduct this experiment. The result showed that the most influenced factor for penetrating length and hollowed core ratio is the short shot size.
9
Wu, Yi-Chiun, and 吳逸群. "low Visualization of the Water Assisted Injection Molding Process." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/07913823981997662717.
Анотація:
博士長庚大學
機械工程研究所
95
Water-assisted injection molding technology has been used to manufacture plastic tubes in recent years, due to its light weight, relatively lower resin cost per part and faster cycle time. This research investigates the filling phenomena of the water assisted injection moulding process by using a flow visualisation technique and deveop a novel high flow rate water pin for water assisted injection molding of plastic parts. Experiments were carried out on an 80-tonne injection molding machine equipped with a laboratory-developed water injection unit. The material used was semi-crystalline polypropylene. A flow visualisation mould was specially designed and made for this study. A high-speed video camera was used to record the mould filling phenomena of rectangular cavities with three-channel geometry and layouts: a flat plate, a plate with two zones of different depths and a plate with symmetric ribs. The interaction between the assisting waterand the polymer melt during moulding was observed, and insight into the water penetration behaviour was summarised. The ring type and orifice type have the disadvantage of low flow rate and high pressure drop, while for the latter one the timing of piercing pin into the cavity is a challenge and the cost of mold is high. The pin, which consists of a sintered porous surface outlet, has been tested against parts with two different geometries: a plate with a channel across the center and a float-shaped tube part. The experimental results suggest that the proposed water injection pin can mold parts of large size with a more uniform residual wall thickness distribution.
10
Ming-Ren, Lin, and 林銘仁. "Water-Assisted Injection Molding of PBT(Poly-butylene terephthalate)." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/39994033345027390909.
Анотація:
碩士長庚大學
機械工程研究所
93
Abstract This report was to experimentally study the water assisted injection molding of poly-butylene-terephthalate (PBT) composites. Experiments were carried out on an 80-ton injection-molding machine equipped with a lab scale water injection system, which included a water pump, a water injection pin, a water tank equipped with a temperature regulator, and a control circuit. The materials used included a virgin PBT and a 15% glass fiber filled PBT composite. A plate cavity with a rib across the center was used. Various processing variables were studied in terms of their influence on the length of water penetrations in molded parts. Mechanical property tests were performed on the water assisted injection molded parts. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) have also been employed to identify the material and structural parameters. In addition, a comparison has been made between water assisted and gas assisted injection molded parts. It was found that the melt fill pressure, melt temperature, and short shot size were the dominant parameters affecting the water penetration behavior. Material at the mold-side exhibited higher crystallinity than that at the water-side. Parts molded by gas also showed higher crystallinity than those molded by water. In addition, the glass fibers near the surface of molded parts were found oriented mostly in the flow direction, and oriented substantially perpendicular to the flow direction with increasing distance from the skin surface.
11
Che-Chi, Liu, and 劉哲齊. "A Study of the Water Assisted Injection Molding of Thermoplastic Elastomers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/67505417568783683777.
Анотація:
碩士長庚大學
機械工程研究所
95
The objective of this study was to manufacture thermoplastic elastomer tubes by a novel water assisted injection molding method and to experimentally investigate the effects of various processing parameters on the molded parts quality. Styrene-ethylene/butylene-styrene (SEBS) compounds based thermoplastic elastomers were used for all the experiments. Experiments were carried out on a lab-developed water assisted injection-molding system, which included a water pump, a water injection pin, a water tank equipped with a temperature regulator, and a control circuit. After molding, the lengths of water penetration as well as the hollowed core ratios in molded tubes were measured. The effects of different processing parameters on the lengths of water penetration were determined. It was found that the shrinkage rate and the viscosity of the elastomer materials, and the void shapes of the hollowed cores mainly determined the water penetration lengths in molded products. In addition, a comparison has been made between the parts molded by water assisted injection molding and gas assisted injection molding. It was found that water assisted injection molded parts mold parts with less residual wall thickness distributions along the water channel. The cycle time for water assisted injection molded parts was shorter than that of gas assisted injection molded parts.
12
Lin, S. P., and 林士博. "Study of the of “Fingering Behavior” in Water-Assisted Injection Molding." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/65101640445877338691.
Анотація:
碩士長庚大學
機械工程研究所
92
Thin, plate-shaped parts of composite materials are usually reinforced with structural ribs. These ribs also serve as water channels with the water-assisted injection molding technology. One of the problems that encountered in water assisted injection molded composites is the “water fingering” phenomenon, in which the water bubbles penetrates outside designed water channels and forms finger-shape branches. Severe fingerings can lead to significant reductions in part stiffness. This study investigated the fingering phenomenon in water-assisted injection molding of short glass fiber reinforced polypropylene parts. Experiments were carried out on a water-assisted injection molding system developed earlier in our lab. A plate cavity with a fish-bone water-channel layout was used for all experiments. The effects of various processing parameters on the fingering were studied. In addition, the influence of water channel geometry, including aspect ratio and fillet geometry on the fingering were also investigated. A numerical simulation based on the transient heat conduction model was also carried out to explain the formation mechanism of fingerings in water assisted injection molded composites.
13
Chin-Chang, Yeh, and 葉金璋. "A Study of the Water Assisted Injection Molding Process with Rubber and Plastic Material." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/69652569169571065572.
Анотація:
碩士清雲科技大學
機械工程研究所
93
In this paper, the Water Assisted Injection Molding (WAIM) technology is applied to the design of a new plastic Injection Molding process. The chief end of WAIM improve the traditional injection molding technology will have the results of uneven product shrink, warpage, residual stress, and so on, which cause great difficulties in the structural design and the outer appearance of the product, for example, large-size tubular and club parts, as well as other modules of complicated shapes. In this study, a novel WAIM system was developed in our laboratory to manufacture plastic composite parts. An experimental study, based on the Taguchi orthogonal array design, was conducted to characterize the effect of different processing parameters on the WAIM of thermoplastic composite parts, including melt temperature, mold temperature, short-shot size, water pressure, water injection delay time, water temperature, and water injection time. The materials used were PP, BS, PC/ABS, and rubber. Major objective is investigate the effects of different processing parameters on the length of water penetration and hollowed core ratio in WAIM parts. Use Analysis of Variance, Grey Relational Analysis and parameter experimental of single are applied to finding the optimal parameters of injection molding process. was conducted to investigate the processing factors that affect the length of water penetration and hollowed core ratio in molded parts.
14
楊恭選. "Design/Molding and Optimization Expert System for Gas-Assisted Injection Molding." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/49404993285044755143.
Анотація:
碩士中原大學
機械工程學系
85
The purpose of this study is to build up the "Design／Molding Guidelines" and expert system for the application of gas-assisted injection molding to assist engineers in product design, mold design and process optimization. The method used in this study is experience and data based expert system, statistical Taguchi approach and neural network analysis. First, an expert system concerning the qualitative and quantitative design／molding rules was constructed. Then optimized processing parameters was obtained by using statistical Taguchi approach and backpropagation. The results were also verified by experiments. Moreover, the possibility of training examples using neural network was evaluated by Taguchi method and the effect of learning rate and hidden node number to neural network learning rate was also investigated. The results of this research are stated as follow: 1. The expert system has been constructed for only for gas-assisted injection molding. It includes gas channel design rules, effects of processing parameters on molding ability, explorations of optimization for processing parameters, evaluations of part strength reinforced by gas channel and data base for hollowed core melt. 2. The experimental results of statistical Taguchi approach shows that the material amount of pre-filling and delay time have major effect on gas penetration length in spiral mold products. Other processing parameters such as mold temperatures, melt temperatures, gas pressure and injection speed has less significant effect. 3. In the analysis which combined the statistical Taguchi approach and backpropagation for evaluating learning rate of network, the usage of 14 processing parameter combinations which is different form the setting of table L18 shows that the learning effect of neural network is very good. Because of the skeleton of neural network used in this study can learn the parameter combinations to be set by L18 orthogonal table in statistical Taguchi approach. There is a better chance to find out the setting parameters for optimization. 4. The combinations of learning rate and hidden node number have best result in the combinations of three hidden nodes and 0.10 learning rate.
15
Hsieh, Wen-Hao, and 謝文豪. "The Intelligent Control of Gas-Assisted Injection Molding System." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09288108772197083376.
Анотація:
碩士國立臺北科技大學
車輛工程系碩士班
91
The object of this research is to develop an intelligent controller for controlling the gas-assisted injection molding system. The application of model based classical control theory needs accurate system''s mathematical model for designing controller. However, in tradition injection molding, the macromolecule plastics is unsteady flowing in the process of being stuffing, so it''s difficult to establish or estimate its mathematic model. In this research, the model-free intelligent control strategy was employed to control the gas-assisted injection molding system. In this study, three control strategies were pro-posed: (1) PID controller, (2) fuzzy controller, and (3) self-organizing fuzzy controller (SOFC) to control the gas-assisted injection molding system. The intelligent controls of the gas-assisted injection molding system control performances were satisfactory by using these control strategies from experimental results shown.
16
Wang, Chia-Chiang, and 王家強. "The High-Pressure Control of Gas-Assisted Injection Molding." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/77225092847543535510.
Анотація:
碩士國立臺北科技大學
車輛工程系碩士班
91
The mathematical model of gas-assisted injection molding system with nonlinear dynamic is difficult to establish accurately. In this study, the model free intelligent control strategies were proposed to control this system for investigating control performances. In addition, the C-Mold software of AC Company in USA was employed to simulate analysis in gas fluid, cooling temperate, pressure distribution and gas blow, respectively. The filling short shot, filling, holding pressure filling, inside stress and deformed distribution after cooling situations in injection molding process were compared to provide an important reference for plastic injection molding in mold design, mold testing and mold manufacturing. The runner and molding conditions were selected for optimum injection molding related with dimension of gate and position design from simulation results shown. In this study, two control strategies were proposed: (1) fuzzy controller, and (2) fuzzy controller with grey prediction. The gas-assisted injection molding system was controlled by using these intelligent controllers, which compared to traditional PID controller to investigate control performances of the system. These intelligent control strategies possess better control performances than that of PID controller for high-pressure control in gas-assisted injection molding system.
17
Tang, Su Ying, and 蘇英棠. "Integrated Expert System for Gas-Assisted Injection Molding Process." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/09694689705110698015.
Анотація:
碩士中原大學
機械工程學系
87
The gas-assisted injection molding process has been very popular in recent years. Although it can certainly help in improving part quality and resolve some difficult problems encountered in traditional injection molding process, the process is truly more complicated with the injected gas. In this system, the fuzzy logic is integrated with knowledge base to create inference engine to store, extract and combine expertise in gas-assisted injection molding process. In addition, Neural Network is used to create the learning ability and Taguchi method is used to find the optimal processing condition. The most important component is CAE analysis that is seamlessly integrated to interpret the result and create part-specific knowledge. The system will provide the total solution for gas-assisted injection molding process and uplift the related techniques and developments.
18
Jung, Peter Ungyeong. "Development of Innovative Gas-assisted Foam Injection Molding Technology." Thesis, 2013. http://hdl.handle.net/1807/43608.
Анотація:
Injection molding technology is utilized for a wide range of applications from mobile phone covers to bumper fascia of automotive vehicles. Foam injection molding (FIM) is a branched manufacturing process of conventional injection molding, but it was designed to take advantage of existing foaming technology, including material cost saving and weight reduction, and to provide additional benefits such as improvement in dimensional stability, faster cycle time, and so on. Gas-assisted injection molding (GAIM) is another supplemental technology of injection molding and offers several advantages as well. This thesis study takes the next step and develops innovative gas-assisted foam injection molding (GAFIM) technology, which is the result of a synergistic combination of two existing manufacturing technologies, FIM and GAIM, in order to produce a unique thermoplastic foam structure with proficient acoustic properties. The foam structure manufactured by GAFIM consists of a solid skin layer, a foam layer, and a hollow core; and its 6.4-mm thick sample outperformed the conventional 22-mm thick polyurethane foam in terms of the acoustic absorption coefficient. With respect to foaming technology, GAFIM was able to achieve a highly uniform foam morphology by completely decoupling the filling and foaming phases. Moreover, the additional shear and extensional energies from GAFIM promoted a more cell nucleation-dominant foaming behavior, which resulted in higher cell density and smaller cell sizes with both CO2 and N2 as physical blowing agents. Lastly, it provided more direct control of the degree of foaming because the pressure drop and pressure drop rate was controlled by a single parameter, that being the gas injection pressure. In summary, innovative, gas-assisted foam injection molding technology offers not only a new strategy to produce acoustically functioning thermoplastic foam products, but also technological advantages over the conventional foam injection molding process. Gas-assisted foam injection molding can become the bedrock for more innovative future applications.
19
Chen, Chien-Hung, and 陳建宏. "Integrated Intelligent System for Gas-Assisted Injection-Molding Process." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/85995438517075780598.
Анотація:
碩士中原大學
機械工程研究所
89
With the growing usage of plastic products, many efforts have been made to raise quality and efficiency. Good and steady quality must take account of whole process procedure for injection molding, including polymer, mold design, process parameters, and molding machines. The process of gas-assisted injection molding has highly complicated all related aspects, including mold design, gas channels, and processing. In addition, most design and processing knowledge are based on trial-and-error experience. An integrated intelligent system is to synthesize the knowledge into computer and use the inference strategies to solve related problems as a real expert. Therefore, this thesis introduces a solution to integrate processing guidelines, design concepts, experimental studies, CAE analysis, artificial intelligence, and Taguchi method to create an integrated intelligent system. The system provides the quantitative guidelines for processing, design of gas channels, mold design, and optimizing method to build up the knowledge about the process. The thesis is to provide an integrated intelligent system by integrating C-MOLD Gas-Assisted Injection Molding, Fuzzy Logic, experimental studies, Neural Network, Expert System, and Taguchi method. The system will provide the total solution for gas-assisted injection-molding process and uplift the related techniques and developments.
20
Tsai, Tsung-Hsien, and 蔡宗憲. "Application of the Gas-Assisted Injection Molding Control System." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/6trqs6.
Анотація:
碩士國立臺北科技大學
車輛工程系所
93
Traditional injection molding machine (TIMM) generally employs an open-loop control strategy for performing injection molding of plastic products.However, such control strategy cannot satisfy for injection molding requirement in complicated geometric shape with large size or hollow plastic products.Therefore, this work developed a closed-loop control strategy to control the TIMM during the filling and holding phases of injection molding;then the high-pressure gas of the gas assisted injection molding system was applied in holding phase of the post-filling process for achieving injection molding of plastic products. The TIMM incorporated the gas-assisted injection molding system that was called gas-assisted injection molding control system (GAIMCS).The GAIMCS is clearly a nonlinear with uncertain system; hence, designing a model-based controller to control it is difficult because its mathematical model is hard to establish accurately.This work proposes model-free intelligent control strategies: (1) traditional fuzzy controller (TFC), (2) grey prediction fuzzy controller (GPFC), and (3) new modifying self-organizing fuzzy controller (NMSOFC),to control the GAIMCS for evaluating control performance of the system. The GPFC and NMSOFC have better control performance in quickening the rise time and reducing the steady-state error than does TFC,as verified by experimental results.
21
Wu, Rui-Zhe, and 吳睿哲. "Water Soluble Core Applied on Injection Molding." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/tjr997.
Анотація:
碩士國立虎尾科技大學
機械與電腦輔助工程系碩士班
104
Some parts’ geometry are complicated and make it difficult finished in one stop injection process, e.g., manifold, container, …, etc. We experimented with using water soluble polyvinyl alcohol (PVOH) patterns to create internal geometries within injection molded parts. The optimal condition of preparation of PVOH and water is investigated first. By over molding sacrificial PVOH patterns with a shell, and subsequently dissolving the patterns, diverse internal features were fabricated with traditional injection molding equipment. Scanning electron microscope (SEM) measurement explains the compressive strength of PVOH pattern from microstructure concept. Metrological study performed on the components has shown that precise control of the internal dimensions is possible over a wide range of processing temperatures and conditions. The study also extends the usage of water soluble polyvinyl alcohol for temporary mold for small quantity manufacture. This process can help develop and mass-manufacture complex parts with internal geometries and undercut features faster and more economically than the industrial alternatives.
22
Hong, Hong-Song, and 洪菘鴻. "Study of Part Properties by Molding Visualization on Gas-Assisted Injection Molding Process." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49745982981646177226.
Анотація:
碩士中原大學
機械工程研究所
101
Gas Assisted Injection Molding (GAIM) is to add gas during filling melt within short shot and to use the compressed gas to be the intermediary of molding and packing. GAIM is a good way to achieve the aim of cost down. Therefore, the hollow area and the penetration length of product are essential factors of quality. Visualization of Molding, Gas Counter Pressure (GCP) and Dynamic Mold Temperature Control (DMTC) are applied to GAIM in this study. By controlling pressure of GCP to discuss how GCP affect the hollow rate on GAIM. The study uses visible-internal mold and a shape of paperclip core to do the experiment with GCP of GAIM. This experiment mainly observes flow field behavior and fountain flow under different GCP pressures with the melt mixing color plastic and high-speed photography and analyses the relationship of penetration length and hollow area in GAIM. Experimental result was compared with Moldex 3D analysis result to generalize the characteristics of GCP. In order to find out how mold temperature affect the quality of product, which is made under GAIM with GCP, the experiment cooperated with the technology of DMTC. By analyzing the relationship of mold temperature and GCP, the study establishes a related database. Since this study uses the internal-visible mold, it is easier to observe the changes of fluid in molding. The result shows that GCP can increase the penetration length and upgrade the quality of hollow rate, though the hollow area is less; also the DMTC can increase the hollow area. Thus, GCP and DMTC both are applied to GAIM can control the hollow area. By fiber orientation observation knows that GCP can make interlayer be in the same direction, which shows that GCP can reduce the shrinking rate of product.
23
Huang, Hsin-Yi, and 黃信義. "Study on Packing Effects of External Gas-Assisted Injection Molding." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/95960128436955762245.
Анотація:
碩士中原大學
機械工程研究所
95
ABSTRACT The polymer has become the basic material of products recently. Then injection molding is widely used in the polymer process. Because of its advantages such as fast, light, low-cost and all-in-one. Nowadays products are getting thinner and larger. The most important thing for products is to prevent shrinkage and warpage, but it is not enough by using melt packing. So external gas molding has developed for solving these problems. In this study, we build a rectangular mold with high L/T (>100). Then we measured pressure by three pressure sensors which installed along the melt flow direction. Finally, we compared the in-mold pressure under the situation that no melt packing, melt packing and external gas packing during molding process. Also we measured mass and shrinkage of products and compared it as well. As a result, Observe from in-mold pressure can obtain, the external gas molding has uniform packing effect at overall molded, and another has good repeatability and stability. External gas preventing shrinkage achieved 70% of melt packing effect, just only making less then 25% in-mold pressure. Using melt packing increase weight with 9.39~9.96% and diversity up to double, when used external gas packing increase less then 1% and diversity up to 1.07 times. Although external gas packing only has melt packing with 56.1~72.7% effect on shrinkage along flow direction, but uniform packing surface agree with thinner and larger article.
24
Kikuchi, Akihisa. "An investigation of vibration-assisted injection molding for enhanced manufacturing /." Diss., 2001. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3036266.
25
Pu, Mei Hua, and 普美華. "Multi-Mediumization of Application Technology for Gas-Assisted Injection Molding." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/53055167955276362640.
26
Yang, Ming-Hsien Ou, and 歐陽銘賢. "Study of Metal Powder Injection Molding Using Gas Assisted Technology." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/tnasnj.
Анотація:
碩士中原大學
機械工程研究所
106
Metal Injection Molding (MIM) is a manufacturing method combining with injection molding process and powder metallurgy process. De-binding process takes the longest time in all process. As the volume of product is large, it will take doubling time on de-binding process. Utilizing the gas-assisted injection molding (GAIM) can let the product be hollow. Therefore, the purpose of the study was to reduce the time on de-binding process by combining with GAIM and MIM. One dimensional tube was utilized to individually investigate the effect of gas assisted injection molding to the traditional metal injection molding on the part density, the hollowed-core ratio, penetration length and shrinkage under varied parameters. The parameters was including that gas pressure, gas holding time, gas delay time and mold temperature. The same measurements were checked for the synergy processes with different shot size after getting the lowest shot size by comparing the effect of different parameters. Besides, the injection pressure and de-binding time in gas assisted injection molding was also compared within different shot size, including full shot. The results of the study show that gas-assisted injection molding applied on metal injection molding can improve the defect of powder-binder separation, and reduce the shrinkage of green part. Because the product’s structure is hollow, the shrinkage by sintering can be reduced. The result of different weight percent show that the injection pressure can be reduced 17.23% in full shot when the shot size was sixty five weight percent, and the time of de-blinding can be greatly reduced.
27
Chen, Yen-Shou, and 陳晏壽. "A Study of the Liquid-Assisted Injection Molding of Thermoplastic Materials." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/03375482395625978080.
Анотація:
碩士長庚大學
機械工程研究所
90
Liquid-assisted injection molding (LAIM) is an attractive idea, and investigated at the beginning of the 70s. The main advantage of liquid-assisted injection molding is the better cooling effective than injection molding (IM) or gas-assisted injection molding (GAIM). It permits shorter cooling times, reduced cycle times for the products. On the other hand, it had economical process medium and low plant costs. The aim of this study was to develop equipment about liquid injection system and investigate the quality of the liquid-assisted injection molded parts of thermoplastic materials. The first part of the research is to investigate the effect of processing parameters in LAIM. Various processing parameters were studied in terms of their influence on the length of liquid penetration in liquid- assisted injection molded parts: melt temperature, mold temperature, melt filling speed, melt filling pressure, liquid temperature, liquid pressure, liquid injection delay time, liquid packing time, and short-shot size. The second part of the research is to optimize the length of liquid penetration in liquid-assisted injection molded parts. An L18 experimental matrix design based on the Taguchi method was used in this part. Experiments were conducted with an 80-ton injection molding machine provided with a liquid injection system by lab-made. The liquid injection system consisted of a liquid tank with the temperature controller, pressure regulator, valves, a solenoid, and a controller for injection time. A spiral mold was used for all experiments. The materials used were general-purpose polystyrene (GPPS), polypropylene (PP), and glass-fiber filled (20%, 30%) PP composite. The process medium used was water. From the experiment results, the some important processing parameters affecting the length of liquid penetration in liquid-assisted injection molded parts were found. Short-shot size, delay time, liquid temperature are the key processing parameters for PP and PP composite materials. Short-shot size, melt temperature, mold temperature are the key processing parameters for PS material. On the whole, it was found that short-shot size is the most significant factor affecting the quality of the process for LAIM.
28
梁源杉. "Investigation of Part Surface Visional Quality in Gas-Assisted Injection Molding." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/88296687500656969963.
Анотація:
碩士中原大學
機械工程學系
85
The main focus of this research was to understand the problems of surface visional quality, by inducing gas flow into plate and the thickness of local part, between gas channel and plate in gas-assisted injection molding. Due to the structure of human''s eyes, a visible object is the composition results of reflection intensity and color changing of object. The former one is the gloss measuring by glossmeter. The latter one can be measuring by chroma meter. So this surface visional quality including glossy difference and chromatic aberration was researcded. This research is to conduct a preliminary study concerning the surface visional quality in gas-assisted injection molding. The literature on the problem wasn''t published much. We first synthesized glossy difference and chromatic aberration to explore, and expected to solve this challenge. In this experiment, we aimed at several conditions to research the influence of glossy difference and chromatic aberration. Such as three kind of resin (PP, ABS, FR90), and eight different process parameters, and five different shapes of gas channels having the same cross-area, and the twelve semicircular gas channels having different radius and different thickness, and etching on core-side, and the gas channel with fillet. This study shows that both the glossy difference and chromatic aberration were found to be the largest while the resin FR90 was used, the least clnomatic aberration was found while the resin ABS was used, and the best glossy quality was found while the resin PP was used as the material. In the influences of various process parameters, we got different results in defferent resin. The major differences were attributed to the fact that the glossy difference was strongly affected by the cooling rate, and the effect of gas packing, and the thickness of the part. Besides, the chromatic aberration was affected by the cross-area of the thickness of the part. For the gas channel, the semicircular gas channel was the best choice in the results of glossy difference and chromatic aberration. For various radius of gas channels and plate thickness of semicircular gas channels, the best surface visional quality was found when R／t is equal to 2.67, i.e. R8t3 case. Adding fillet at gas channel and etching on core-side were helping in improving the chromatic aberration and glossy difference also.
29
Li, Ming-Hung, and 李明樺. "Warpage Control of Headlight Lampshades Using External Gas-assisted Injection Molding." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/44941297871544360687.
Анотація:
碩士國立高雄第一科技大學
機械與自動化工程研究所
102
Headlight Lampshade is characterized with large, uneven part thickness, as well as large-area geometrical curvatures, which is ease of creating uneven shrinkage during injection molding and thereby a severe warpage defect occurs. This study comprises of three parts: (1) investigating the influence of a commercial simulation software to optimize the injection mold used for headlight lampshades; (2 ) examining the influence of conventional injection molding parameters on injection molding qualities; (3) verifying the influence of external gas-assisted parameters on injection molding qualities. The experimental results indicate that: (1) changing gate locations enables better flow balance and the filling pressure is reduced 26%; optimal design of coolant channels has significant improvement on mold temperature distribution; optimal setting of holding pressure and holding time has a better volumetric shrinkage control with a significant decrease of shrinkage (about 57%). (2) using tempering to setting of holding parameter can improve deformation 26%; setting of optimal holding parameter can improve deformation about 10%; (3) control the delay time and pressure of external gas-assisted has a better volumetric shrinkage, and compared to tempering of optimal holding parameter can improve deformation about 49%.
30
Huang, Yung-Ming, and 黃永銘. "Microgear Injection Molding Assisted with the Robust Process Parameters Setting Method." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72798t.
Анотація:
碩士國立高雄第一科技大學
機械與自動化工程所
96
Micro-injection molding, with advantage of mass-production capability and low cost, is one of key technology in producing precision-molded components. Unfortunately, a low yield rate of high quality is frequently observed due to its problems with size and shape precision, warpage, molecular orientation, and optical properties. The solution to the problems mentioned above is involved in machine consideration, molding design, and process parameters setting. However, robustness performance for the parameters, even the optimal combination, remains less attainable when an alternation to parameters occurs with change in the environment where the machine has been running for a long while. Therefore, the purpose of the study is to search a setting point through Robust Process Parameters Setting Method which focuses on multiple quality characteristics, in the hope that the process parameter is able to endure change in the environment and to obtain the optimization for multiple responses and the yield rate. Gears with 6 mm outside diameter and 4 mm outside diameter are applied in this study and the mold insert is made by LIGA-Like process. The first phase is concerned with the analysis of two single quality characteristics, including the error of outside diameter and the error of tooth thickness by Taguchi method. The second phase is to find a quality indicator interprets multiple response problems exactly by PCA, WPC, or DF method. The final phase is to search a robust parameter setting point by Robust Process Parameters Setting Method and confirmed by experiment. The results show that in first phase, the effects of parameters on single quality characteristic for 6 mm gear are similar to 4 mm gear. The important factors for outside diameter are mold temperature, injection speed, and back pressure. In addition, factors for tooth thickness include holding pressure, cooling time, and mold temperature. The results of second phase indicate that mold temperature, holding pressure, and injection speed give significant effects to multiple quality characteristics for 6 mm gear. Nevertheless mold temperature, holding pressure, and cooling time are for 4 mm gear. Finally, the results for Robust Process Parameters Setting Method show that compared with the initial point, yield rate of 6 mm gear produced in robust setting point searched by the method increased from 10% to 91%. As for 4 mm gear, yield rate increased from 38% to 93%.
31
Yi-Jen, Yang, and 楊逸仁. "Process characteristic of ultrasonic assisted injection molding in the plate processing." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/utw49g.
Анотація:
博士國立高雄應用科技大學
模具工程系
106
Polymer processing is a crucial and diverse field in the manufacturing industry. We investigated the process characteristics and effects of injection molding using ultrasonic vibration. An ultrasonic device was installed in an injection mold; polymer was directly vibrated during injection, the ultrasonic energy transfer into the melt, thereby changing the polymer melt flow field, improve the quality of the product. In this paper, three flat specimens (75mm x 47mm x 3mm/1mm/3 & 1 difference thickness) of ultrasonic-assisted injection mold were developed and a 45mm diameter ultrasonic vibration device was set up in the central of cavity with frequency of 20 KHz to vibrate Polycarbonate and Polymethyl methacrylate (PMMA) melt. Besides, cavity pressure sensors were located on the front and rear of the vibration region. The external the timing control system was installed on ultrasonic oscillator, to analyze the melt flow behavior and product quality between ultrasonic assisted injection molding efficiency and injection molding conditions. In this paper, a case study of three different thickness flat specimens, ultrasonic assisted injection molding can be converted into kinetic energy required for the polymer melt to reduce the thickness of the solidified layer and improve the flow characteristics of the melt, and change the melt flow behavior around the skin layer to reduce the molecular orientation and high shear effect. Furthermore, the freezing rate of the melt was reduced; thus, the amount of melt pressure lost through the cavity was decreased and the residual stress inside the injection-molded component generated during the photoelastic stress analysis was lower, and the delay the solidification rate of the melt solidified layer in order to eliminate the glass fiber streaks, floating fiber, changing alignment, improve product surface strength and race-track effect.
32
Tsai, Yi-Cheng, and 蔡逸誠. "The Research of Warpage for Gas-assisted Injection Molding by Taguchi Method." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/03827527340416084259.
33
Dong, Jhi Gang, and 董志剛. "Inveestigation of Process Parameters Effect on Molding Window and Part Surface Quality in Gas-Assisted Injection Molding." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/86232835231436289733.
Анотація:
碩士中原大學
機械工程研究所
84
The research purpose of this thesis is to conduct the experiments of gas-assisted injection molding to understand the effect of process parameters and gas channels on gas penetration molding windows and the quality of part.It also investigate the influence of gas penetration from different types and installed positions of gas needles. Based on the research results,the application of gas-assisted injection molding to the production of three automotive parts were demonstrated. From the present studies, the following observations have been found: 1.To obtain reasonable molding window, the ratio of gas channel height to part thickness be greater than 2 no matter the cross section of gas channel is semicircular or rectangular,the ratio is higher than the parts moldability is much better. In the case of rectangular gas channel ,the channel width to height ratio will also affect the molding window. 2. The effect of process parameters on part surface quality in gas-assisted injection molding for amorphous and crystalline polymer are quite different.3. For different design of gas channels, if the position of the hollowed core within the gas channel is higher, then the glossy of the part surface is better. And if the inertial moment of gas channel is higher, then the flatness is much better.4. One will obtain best quality in using the trapezoid gas channel section associated with top rib both moldability and part surfaced. 5. Three different types of gas needles installed at different heights of the gas inlet and different melt temperature were found to influence clog in the llowing way.
34
Juang, Ying-Jie, and 莊英杰. "Numerical Simulation of Gas Penetration Phenomenon in a Gas-Assisted Injection Molding Process." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/42450690729954907791.
Анотація:
碩士中原大學
機械工程研究所
95
The numerical prediction of three-dimensional melt filling and gas penetration in a clip-shaped square tube is conducted using a compressible model in this paper. The application of a finite volume discretization and volume-of-fluid method has been demonstrated to simulate three-dimensional gas-assisted injection molding processes. The modified Cross model and Tait Equation are implemented in the numerical scheme in order to describe the rheological properties of polymers. With the help of available experimental measurements, the numerical results of our three-dimensional compressible model are proven to have high prediction accuracy.
35
Lee, Yun-Ping, and 李芸蘋. "A STUDY OF TEACHING MATERIALS FOR COMPUTER ASSISTED INSTRUCTION ON PLASTIC INJECTION MOLDING." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/kenx4f.
Анотація:
碩士大同大學
機械工程學系(所)
95
This research is aim on the basic knowledge and skill in plastic injection molding domains on which a mechanical engineer should required. The job training material is based on the principle of computer assisted instruction (C.A.I.) with fully discussed about the principle of plastic injection molding, the structure of plastic injection machine, the design of plastic parts, and plastic simulation software lessons. Teaching program is mainly divided into three chapters. I Computer Assisted Instruction C.A.I. system helps users to integrate experience, knowledge, and skill learning from job. Each of its unit lessons is designed with programmed instruction which develops vertical thinking and lateral thinking. Through repeatedly practice makes learning effectively. Theory：Explain the principle of plastic injection molding, why plastic molding defective, and how to deal with it. Users will realize the basic knowledge of plastic injection molding after learned this lesson. (2) Teaching: Explain the basic principle of plastic parts design. Describe how to inspect plastic parts to determine its condition by using illustrations of plastic parts design experience. Teaching users to operate software Plastic Advisor building in Pro/Engineer. (3) Testing: Provide Quizzes about chapters of Theory and Teaching in order to know the users’ learning results.(4) Interflow: Teach users design plastic parts by using the truly designed upper shell, battery cover, and buttons as plastic parts design model, also shows the key points of design and experimental designing value. II Electronic Book (1) Teaching material: Use computer software to classify key points and illustrate from job experience.(2) Memo: In learning procedures, use notepad to get down the key point and progress, as a personal database. III. Interflow on line E-mail provided the connection of users and teachers for communication and discussion to solve questions in using teaching programs. The latest news and information posts on research laboratory website provide multi-learning path for users and teachers.
36
Hsu, Chih-Chung, and 徐志忠. "Three-Dimensional Flow Analysis for the Simulation of Fluid-assisted Injection Molding Process." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/92g2vx.
Анотація:
博士國立清華大學
化學工程學系所
105
Fluid-assisted injection molding (FAIM) process has brought a breakthrough development for the traditional injection molding industry. The fluid cores out a network of hollow channels throughout the mold cavity to reduce the cost of energy and plastic evidently. In the recent years, the improvements both in the numerical methods and computer hardware have promoted the application of CAE in the modeling of the injection molding process. The major drawbacks of the Hele-Shaw approximation, commonly used today as a means of simplifying the simulation of FAIM process, are the inherent loss of the ability to predict the important physical three-dimensional phenomena for fluid penetration such as blow-out behavior, corner effect, secondary penetration and the finger effect. This study presents an implicit finite volume approach to simulate the three-dimensional mold filling problems encountered during the injection molding. The described numerical model deals with the three-dimensional non-isothermal flow of incompressible, non-Newtonian fluids with moving interfaces. The collocated finite volume method and the SIMPLER (Semi-Implicit Method for Pressure Linked Equations Revised) segregated algorithm are used to discretize and solve the flow governing equations. All vector or tensor variables are computed in their Cartesian components, and hence no coordinate transformation is required, which considerably simplifies the complicated fully three-dimensional primitive variables flow calculation. In addition, a high resolution interface capturing scheme M-CICSAM (Modified-Compressive Interface Capturing Scheme for Arbitrary Meshes) is adopted to solve the advection equation to capture the sharp interface on a Eulerian framework. In order to verify the accuracy of this preliminary study, the study first review the predictability of this developed method in the general common free surface and fluid penetration calculation example. Further this study investigates the analysis on relatively simple geometry of three-dimensional mold to study the general 3D phenomena in FAIM process, such as primary and secondary fluid penetration, and fingering effect in order to verify the correctness of the current approach. Moreover, diverse full shot FAIM processes such as overflow and pushback molding process verify mutually with the experimental results on industrial applications. The results show that our novel three-dimensional numerical model is able to predict the complex fluid penetration behaviors in the real mold and the predictions are also consistent with the experimental results to further verify the accuracy of our approach.
37
Wang, Chi, and 王齊. "Application of Gas-assisted Injection Molding on the Lightweight Push-bike Frame Design." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7mkm34.
Анотація:
碩士遠東科技大學
機械工程研究所在職專班
107
Balanced scooter is a popular children's car. The pedal-free bicycle that is born because the child's muscles are not yet mature makes it use step by step. The finished product needs to be firm and beautiful. In order to get the best appearance, the finished product is usually as much as possible. Integrally formed, but at the same time, the thickness of the finished product is too thick, resulting in an increase in weight and failure to meet the requirements. Therefore, the internal hollowing of the finished product is performed by means of gas-assisted injection molding, and attempts are made to reduce the weight of the finished product. The gas-assisted injection molding process firstly performs the injection of the plastic into the film cavity, and then introduces the gas into the melt. The commonly used gas is an inert gas of nitrogen, and the gas flows to the low pressure and high temperature regions of the product along the direction of the least resistance. As the gas flows through the article, it hollows out the cross-section beyond the thick wall by melting the plastic. These hollowed out plastics fill the rest of the finished product. When the filling process is completed, the gas continues to provide the holding pressure to solve the problem of volume shrinkage during the cooling process of the material, but it is difficult to control the gas-assisted injection molding. If the traditional method is used, it is necessary to carry out experiments to find the best gas assist. State, for this reason, this simulation experiment decided to use the mold flow analysis software Moldflow for simulation. Moldflow mold flow analysis software performs gas-assisted injection molding simulation on the actual finished product, which can save the cost of large test and modification of the mold, and can find possible problems and the best choice first. The finished product used in this discussion is the rocker body. The original meat thickness and weight exceed the customer's requirements. It is difficult to solve in the past. I decided to use Moldflow for gas-assisted injection molding to simulate the hollowing out and try to find the best flaw. Empty state. The process of this discussion is to fix the injection velocity value and the injection pressure value, and modify the gas pressure to 10 bar, 15 bar and 20 bar, and the injection capacity is 60%, 65% and 70%. The injection position is the end injection and the central injection, the gas inlet. The position is at the end and the center, and finally the overflow channel is added for experiment, and the content is discussed to distinguish the injection position from the gas inlet position, and the gas pressure and the injection capacity are respectively discussed in three different states. The results show that under the condition that the finished product is selected at the end of the finished product and the position of the gas gate is not good, the amount of gas-assisted injection can be hollowed out, and the end of the flow is insufficient, which causes it to fail to meet customer demand. After maintaining the original gate position and changing the gas gate position, the amount of voiding is significantly improved but the flow end is easily vented, and the addition of the overflow passage does not help. To this end, the gate position is changed to the center of the finished product, so that the flow at both ends is balanced. After changing the position of the gas gate, it is found that the amount of hollowing is still insufficient, so the overflow passage is added at the end of the finished product, and the result shows that the gate position and the air pressure position are displayed. Change to the center of the finished product, and add the overflow channel. After adjusting the gas pressure to 15 bar and the filling amount of 70%, you can find the best hollowing state of the finished product 30% hollow.
38
Su, Bo-Chang, and 蘇柏菖. "3D Temperature Measurement in Water-Assisted Injection Molded Parts." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/s826df.
Анотація:
碩士長庚大學
機械工程研究所
96
Water-assisted injection molding technology has developed rapidly in recent years, due to its some prime advantage improve a lots problem of traditional injection molding technology.The material used was semi-crystalline polypropylene. Choice of parameter is a important step in experimental process that it affect production’s quality. The objective of this study was to manufacture thermoplastic thick-workpiece by a novel water assisted injection molding methoding and investigate temperature trend of workpiece inside in different time. In the past, few research of temperature measure was dead against intramural investigation of thick-workpiece in njection molding technology. We make use of two metrical methods to acquire diffenent temperature trend of injection molding and chase down optimum temperature curve that it was compared with experimental result.Temperature control of material can insure all operational all right and temperature is parameter of most importance in injection molding process ( pressure is secondary parameter ). It is found that shear heating and heat conduction had considerable effects on the changes in melt temperature during the flow, with the melt temperature changing continuously with injection time. Experiments were carried out on a lab-developed water injection-molding system, which included a water pump, a water injection pin, a water tank equipped with a temperature requlator, and a control circuit. Thermocouple strike into melt directly by two fixed methods to measure actual temperature trend of workpiece’ interior section. We use Ansys to simulate temperature distribution with injection time. At last, we must find out error factor and improve on improper methods. Water-assisted injection molding has faster cooling efficiency than gas-assisted injection molding and shear heating bring about melt’s temperature increase in initial moment of injection molding process . We must consider specific heat change of melt with injection time in order to as stimulant’s condition. At last, experimental result was compared with stimulant’s data. Ketwords: shear heating , heat conduction , temperature trend , cooling efficiency
39
Nanjunda, Sachin. "Multi-branched tubular components using water-assisted injection moulding." Master's thesis, 2018. http://hdl.handle.net/10400.8/3709.
Анотація:
The development in automobile or consumer product industries is rising drastically. The complexity of the parts and limitations in design and manufacturing suppress the requirements of potential customers in production. The automotive or consumer products parts has become more and more complex with dimensional variations, curves, multi branches and connections especially using metals, results in higher production cost.
Production of hollow plastic parts with complex geometries and several branches is a challenge for moulding industries. Water-assisted injection moulding (WAIM) technique provides a solution for these challenges when compared to the traditional injection moulding techniques. The primary objective of this work is to define new methods to produce hollow polymeric parts with several branches and complex geometries using computer simulations. We will study the WAIM process with different parameters and water injection approaches (i.e., using a single water injector and multiple water injector) and validate with experimental work. As this is a complex challenge, we have used computer simulations using Moldex3D software for the WAIM technique to optimise the operational parameters including the injection points for both plastic and water and additional gates to serve as a starting point for the experimental work and verification of the computer simulations. We use a standard water-assisted injection mould and machine as a test-bed to study the WAIM process to produce a branched tube with a diameter of 20 mm and a length of 315 mm, using both single injector and multi-injector systems. We will present the variation of the injection parameters and their influence on the final product quality. We have identified one mode of operation which leads to a substantial saving in the mass of plastic used to produce the parts. This innovative work will influence on the production of multi-branched and complex geometry hollow parts, which will effectively reduce the overall production time, raw material savings and eliminates the post-processing work on moulded polymeric parts.
40
Su, Chien-Chia, and 蘇建嘉. "Study on the Part Surface Quality of Rib with External Gas-Assisted Injection Molding." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/13594848234016453853.
Анотація:
碩士中原大學
機械工程研究所
95
Accompanying with the I.T. industry develops vigorously; more and more people ask for stylish design, strength quality and good looking of products. Traditional Injection Molding Process can’t afford the desire of the market, and most high quality products need to be reprocessed. Therefore, External Gas-Assisted Injection Molding not only can enhance Part Surface Quality and strength but also make design flexible and variety. It applied to 3C products fittingly nowaday, but there still has short of relative references of the process. Following the thesis, we would study on the ABS material which widely applied in 3C products; by using a flat that length 100mm, width 50mm and thickness 1.5mm and design four different products with different proportion of ribs. The rib each is 0.6, 0.8, 1 and 1.2 times with three different part surfaces which are surface polishing, 8000 mirror polishing and TH-114 etching. When investigating External Gas-Assisted Injection Molding; first, we found out the shrinkage depth depends on the process parameter of the products. Second, according to the result of the experiments; we develop an External Gas-Assisted Injection Molding with the best process parameter and compare with the traditional Injection Molding Process, which in order to observe the best benefit of improving products’ appearance. At last, compare the two processes’ reduce part weight ratio. According to the research, the temperature, gas pressure and gas packing time of process parameter influence most to products’ shrinkage depth. Higher temperature of molding causes thinner freeze layer and that helps rising gas packing time effective. Meanwhile, the depth rib area needs more gas pressure and longer gas packing time that makes melt push forward to the surface continually and reach to better quality. At using External Gas-Assisted Injection Molding in best process parameter; in comparison with traditional Injection Molding Process, it can decrease the shrinkage depth of surface. During the general polishing we decrease to 0.68mm and mirror polishing decreased under 0.89 μm. By eye-investigating on the surface quality of the three different products, the one using External Gas-Assisted Injection Molding can remove sink marks. As mention to the experiment of reduces part weight; three different molding surfaces which use External Gas-Assisted Injection Molding could reduce products, gravity effectively from 1.67% to 3.19%.
41
Hsu, Ting-Hau, and 許庭豪. "The Research of Warpage for Gas-assisted Injection Molding Parameter by Taguchi Experiment Method." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/77534867144991167896.
42
Tseng, Tian Jenn, and 曾添振. "Analysis of CAE and Gas-Assisted Injection Molding Process by Applying Taguchi Quality Engineering." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/09222746683729278898.
Анотація:
碩士中原大學
機械工程研究所
83
The study of Taguchi quality engineering shows application to car-bumper and drinking-cup by CAE results and gas-assisted injection molding. Firstly, the results of CAE show the optimum design of process conditions, and presents the methodology to help product engineer. The object of simulation is to shorten the mold-testing and producing time. In the second application, the analysis of gas-assisted injection molding process and mechanical properties are also based on the Taguchi methods and statistical verification. The gas penetration length, width, the area of hollow cross section and mechanical properties are studied. This study presents(1)the trend of reducing injection pressure and clamping force (2)the influence of the injection molding process condition (3)the combination and efficiency of levels for control factors that will lead to optimal design on the sealing system (4)the factors of affecting greatly to sealing performance for car-bumper and drinking- cup by integrating the L9 orthogonal array of Taguchi methods and the CAE results. For the application of gas-assisted injection molding, this thesis discusses the use of L18 orthogonal array of Taguchi methods to analyze (1)the influence of the process conditions for gas penetration length, width and the area of hollow cross section, and the process optimization lead to the robust design (2) the influence of the process condition for mechanical properties (3)the tensile, bending and impact properties in comparison with the different gas-channel diameter, then testing the influence of gas-channel diameter for mechanical properties. Finally, this thesis not only studies the CAE and gas-assisted injection molding by Taguchi methods but also establishes the design guidelines that help designers.
43
CHOU, HONG-LIEH, and 周鴻烈. "Study on Residual Wall Thickness of Rod-Shaped Parts in Gas-Assisted Injection Molding." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/33875723585931274256.
Анотація:
碩士國立臺灣大學
機械工程學系研究所
86
To be applied to rod-shaped parts producing, gas-assisted injection molding do es very well in sink marks eliminating, material saving and cycle time saving. Rod-shaped parts used to be changed in cross-section which tend to cause accu mulations of melt in corners. Generally, design rules suggest using fillet to avoid accumulations of melt but without rules to follow, and the angle of fill et is arbitrarily decided. The residual wall thickness is determined by temper ature field, gas flow field and the geometric shape. In the magnified tube, us ing 45 degree's fillet can make the residual wall thickness smooth; on the oth er hand, if in the shrunk tube, 15 degree's fillet is suggested. Furthermore, owing to the nature of gas to go along the path of less resistance, the inner wall thickness used to be smaller in the area with radii. However, after 90 de gree, this situation will be improved. Melt fracture results from the conditio n of melt flow from smaller to larger tube which causes ununiform residual wal l thickness.
44
Huang, Hsuan-Yuan, and 黃宣淵. "Study on the Gas Counter Pressure in Gas-Assisted Injection Molding by Melt drag." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/58739064648125154580.
Анотація:
碩士中原大學
機械工程研究所
103
Gas-assisted injection molding technology(GAIM) a kind of green energy in plastic injection molding, which is injecting gas into the short shot melt in the packing stage. Compressed gas is used as the medium to push melt and maintain pressure. Thus, plastic can be saved effectively to reduce carbon. Though gas-assisted injection molding has some great improvements in injection quality, compressed gas is still not easy to control preciously, therefore, the final applied products have some defects such as insufficient penetration length, uneven thickness and uneven shrinkage which affects its appearance. Melt flow resistance of gas penetration is the main factor affecting the manufacturing process, and the gas pressure in packing stage would affect the gas penetration. The pressure sensor is installed in the flow pipe, and control the pressure by the adjustable parameters. Gas Counter Pressure (GCP) technology is applied on Forming Injection Molding to control the direction of the bubble size, so as to improve the molding quality. The study uses the mold core with the shape of paperclip to discuss how the gas counter pressure works in gas-assisted injection molding by melt drag test. Observing how the flow changes by controlling the gas counter pressure and auxiliary gas injection pressure at a constant pressure difference (60bar, 70bar, 80bar and 90bar). And analyzing the relationship between penetration lengths, melt drag flow and molding parameters. This study discussed the effects of counter pressure mechanism on gas-assisted injection molding process and established the database about the mold flow resistance of counter pressure. Experimental results show that the main factor of counter pressure affecting melt resistance is the viscoelastic behavior of the melt in gas-assisted injection molding. The greater the pressure is, the more melt viscosity became. The proper constant pressure difference helps to inhibit melt flow effect Fountain Flow Effect and helps to produce a hollow. Low constant pressure difference forming product is not easy. Constant pressure difference at high pressures was no significant difference about penetration length, unable to play a benefit.
45
Hsieh, Lin-Hsiang, and 謝琳祥. "The Study of Gas-Assisted Injection Molding Process by Applications of Computer-Aided Engineering." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/2jtn49.
Анотація:
碩士中原大學
機械工程研究所
92
The technique of Gas Assisted Injection Molding (GAIM) has been widly applied in Taiwan industry. Due to the compressibility of gas, the difficulties of precisely control and the sensitivity to the operation of surroundings, it is easy to make molding condition unstable in the molding process. Although injection machine takes precisely control in both injection stroke measurement and melt temperture, both factors quite affect the repeatability and stability of GAIM product quality. To choose from the related processing parameters by either traditional experiments or method of trial and error, only increases manufacture cost and failure rate. Using computer aided engineering (CAE) to simulate plastic filling, gas injection and holding pressure stage in GAIM, engineers can adjust processure based on analysis. This report is to use Moldflow software to collect information from a molding period of GAIM. It is to study and research each process parameter in an individual GAIM case using the single-parameter method. Furthermore, it utilizes Taguchi method and Variance analysis to find a key process parameter, then verifing the result with this parameter. In the first case, the main factor which influences gas penertation are gas pressure, plastic melting temperture and short shot percentage in sequence. In the second case, the main factor is the gas delay time. The difference is obvious for the distribution of gas penetration between the simulation analysis and the practical injection result. However through the practical injection improved experiment using the key process parameters from Taguchi method, the result does have a better distribution of gas penetration and the output has no sink mark on the product surface.
46
Chang, Yeong-Shyi, and 張永錫. "Experimental Study and CAE Simulation of Gas-Channel Balancing On Gas-Assisted Injection Molding Process." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/84908919359207962630.
47
TAO, JIE, and 陶捷. "Application of ultrasonic assisted injection molding on the improvement of melt flow and floating fiber." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/29980560949686579707.
Анотація:
碩士國立高雄應用科技大學
模具工程系碩士班
102
This study was to investigate the ultrasonic technology used in assisted injection molding. Applying the ultrasonic devices installed in the mold directly vibration on the polymer melt, the ultrasonic energy transfer into the melt, thereby changing the polymer melt flow field, improve the quality of the product. In this paper, three flat specimens(75mm x 47mm x 3mm/1mm/3 & 1 difference thickness) of ultrasonic-assisted injection mold were developed and a 45 mm diameter ultrasonic vibration device was set up in the central of cavity with frequency of 20 KHz to vibrate Polycarbonate (Teijin L-1225Y) melt. Besides, cavity pressure sensors were located on the front and rear of the vibration region. The external the timing control system was installed on ultrasonic oscillator, to analyze the melt flow behavior and product quality between ultrasonic assisted injection molding efficiency and injection molding conditions. In this paper, a case study of three different thickness flat specimens, ultrasonic assisted injection molding can be converted into kinetic energy required for the polymer melt to reduce the thickness of the solidified layer and improve the flow characteristics of the melt, and change the melt flow behavior around the skin layer to reduce the molecular orientation and high shear effect. It also postpones the frozen rate to eliminate the glass fiber streaks and delay the solidification rate of the melt solidified layer in order to eliminate the floating fiber, changing alignment, improve product surface strength, improve the race-track effect.
48
Parng, Shaw-Hwa, and 龐紹華. "The experimental research of the geometry arrangement of symmetrical ribs in gas-assisted injection molding." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/11503450951486906094.
49
Wu, Chien-Chou, and 吳鑑洲. "Optimization and Simulation for Gas-Assisted Injection Molding with Counter Pressure by the Taguchi Method." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/11825403794423892882.
Анотація:
博士中原大學
機械工程研究所
105
Gas-assisted injection molding (GAIM) means that, during the filling stage, gas is injected into short-shot melt. Compressed gas is used as the packing medium to push the melt to form hollow sections and keep the sections from shrinking. This process significantly reduces material usage and costs. Therefore, in terms of the quality of molded parts, requirements are made based on penetration length and hollow percentage. This study applies a gas counter pressure (GCP) mechanism to GAIM in order to control the meltfront action of melt, change the penetration length and hollow percentage. The influence of factor level on the hollow percentage and penetration length was discussed by experiment and simulation analysis through the Taguchi Method.. The influence of process parameters on mechanical strength was also discussed. The molded part of this study is designed into the paperclip-shaped, and GAIM with a GCP mechanism is adopted in the experiment. Four control factors: counter pressure, melt temperature, gas-assisted pressure, and delay time. This study employs the L9 Orthogonal Array to design an experiment, according to the factor level of each group, the penetration length and hollow percentage of each group were discussed and compared, and a set of verification groups was grouped. The results of the verification group could show that when using the Taguchi method, S/N ratio is particularly significant, the S/N ratio of another quality characteristic can be used to help achieve the goal of optimal factor level combination. In this study, we establish the same model as the experimental product in the simulation software. According to the factor level of each group in the above experiment, the simulation results show that the penetration length and the hollow percentage of each group are discussed and compared. Compared with the experimental results, the difference between the two, the experimental verification group for simulation, the results show that the verification group in the penetration length and hollow percentage data are greater than other groups. In this study, the mechanical strength of the part is further tested, including the bending test and the impact test. The relationship between the forming conditions and the mechanical strength is discussed. , It was found that the bending strength and impact strength of the near counter pressure were greater than the bending strength and impact strength of far counter pressure. The two tests in the verification group is also greater than the strength of other groups, that is, when the hollow percentage of product is larger, the density of the product will be larger, the relative mechanical strength will be larger
50
LI, KUI-YU, and 李奎昱. "The Study of Forming Quality of the Counter Pressure Mechanism on Liquid-assisted Injection Molding." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/q6rnxz.
Анотація:
碩士中原大學
機械工程研究所
102
Liquid-Assisted Injection Molding(LAIM) is short shot filling plastic melt. When center layer plastic melt under melting state add liquid let finished presented hollow. The purpose is Use hollow forming and liquid feature can reached save materials and upgrade finished quality. In LAIM, The assisted liquid penetration capability is impact process main factor. Liquid penetration capability than gas higher and Incompressibility capability easy produce finished center layer orderless. Impact liquid penetration capability parameters is liquid pressure and temperature. Control Pressure need mobile directions install pressure sensors, and use liquid assisted machine variable adjustment changes, and observation pressure changes for finished impact. Control temperature need near mold side install temperature sensors, and mobile directions outside pack insulation foam reduce heat diffuse. In this study, use visualization mold and paperclip shape mold insert. Record Gas Counter Pressure(GCP) under finished plastic melt flow state and liquid penetration capability and epidermal layer thickness changes by the visualization window and the plastic join particle. GCP LAIM and GCP GAIM make than penetration capability and thickness changes. Use changes liquid viscosity , the study of viscosity for liquid penetration capability impact. Get on GCP applications in LAIM mold flow analysis and real mobile state prove. Complete LAIM combined GCP database. The results of Experiments analysis, join GCP can subjoin liquid penetration stability, although reduce finished hollow area, but can upgrade finished penetration length cause overall penetration average. In GCP LAIM and GCP GAIM compare section. LAIM because liquid incompressibility and thermal fast, so it need forming pressure hold time short in penetration average and stable also than GAIM. Improve injection liquid viscosity can change heat conduction and viscous force, further change finished penetration length and hollow area.