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دسترسی آزاد مقاله
1 - Experimental and Numerical Investigation of Injection Molding Main Parameters’ Effects on Shrinkage and Warpage of a Thin Sheet Made of HDPE
Ali Massah Nathan Jafarian Jam Ehsan SouryInjection molding is one of the common processes for producing plastic parts. In this process, the mold is filled immediately and then the part and mold will be cooled down during the packing time. In the end, the part will be ejected from the mold. In this study, the e چکیده کاملInjection molding is one of the common processes for producing plastic parts. In this process, the mold is filled immediately and then the part and mold will be cooled down during the packing time. In the end, the part will be ejected from the mold. In this study, the effects of the most important processing parameters such as packing time, melt and mold temperature have been investigated on shrinkage and warpage of the products experimentally and numerically. According to previous reports, a thin sheet is defined by a length to thickness ratio of at least 100. MOLDFLOW software has been utilized to obtain the numerical results. For the empirical study, 64 specimens have been produced in different production conditions. These samples have been scanned by a 3D scanner and results have been analyzed by CATIA software. The findings show that increasing melt and mold temperature decreases the warpage amount and rises the shrinkage in the specimens. Also increasing the packing time up to 2 seconds increases the warpage and decreases the shrinkage noticeably but in longer packing times the variations will be less remarkable. Moreover, findings show that the general trend in simulated and experimental results are similar in all reported values of shrinkage and warpage, in which the maximum calculated errors for both of them are approximately 10%. پرونده مقاله -
دسترسی آزاد مقاله
2 - Experimental Study of Packing Time and Melt Temperature Effects on Shrinkage of a Thin Sheet Made of Wood-HDPE Composite
Siavash Sobhani Nathan Jafarian JamInjection molding is one of the most common processes which are used for manufacturing different plastic parts. This method includes 3 continuous steps: filling of the mold, cooling and driving the part out. A wide range of plastic and Non-Plastic materials can be used چکیده کاملInjection molding is one of the most common processes which are used for manufacturing different plastic parts. This method includes 3 continuous steps: filling of the mold, cooling and driving the part out. A wide range of plastic and Non-Plastic materials can be used as raw material in this process. One of the most important advantages of this way of production is that it is very economic. In this study packing time & melt temperature effects on shrinkage of a thin sheet made of wood- HDPE composite has been investigated. Based on previous works, defining a thin sheet means the ratio of length to thickness of it should be at least 100. The results were obtained after manufacturing of different pieces and 3D scanning using CATIA software package. Finally the results were represented and compared using EXCEL. Main parameters such as packing time and melt temperature were studied in 4 levels. The method used for designing of experiments is full factorial. The main goals in this study were to reduce the number of defected parts and recommend appropriate process parameters to producethin sheetsmade of wood-HDPE composite. Having this information will result in saving time and reducing the production costs. It has been seen that by increasing the packing time and lowering the temperature, the shrinkage was reduced. پرونده مقاله -
دسترسی آزاد مقاله
3 - Finding efficient frontier of process parameters for plastic injection molding
Wu-Lin Chen Chin-Yin Huang Ching-Ya HuangProduct quality for plastic injection molding process is highly related with the settings for its process parameters. Additionally, the product quality is not simply based on a single quality index, but multiple interrelated quality indices. To find the settings for t چکیده کاملProduct quality for plastic injection molding process is highly related with the settings for its process parameters. Additionally, the product quality is not simply based on a single quality index, but multiple interrelated quality indices. To find the settings for the process parameters such that the multiple quality indices can be simultaneously optimized is becoming a research issue and is now known as finding the efficient frontier of the process parameters. This study considers three quality indices in the plastic injection molding: war page, shrinkage, and volumetric shrinkage at ejection. A digital camera thin cover is taken as an investigation example to show the method of finding the efficient frontier. Solidworks and Moldflow are utilized to create the part’s geometry and to simulate the injection molding process, respectively. Nine process parameters are considered in this research: injection time, injection pressure, packing time, packing pressure, cooling time, cooling temperature, mold open time, melt temperature, and mold temperature. Taguchi’s orthogonal array L27 is applied to run the experiments, and analysis of variance is then used to find the significant process factors with the significant level 0.05. In the example case, four process factors are found significant. The four significant factors are further used to generate 34 experiments by complete experimental design. Each of the experiments is run in Moldflow. The collected experimental data with three quality indices and four process factors are further used to generate three multiple regression equations for the three quality indices, respectively. Then, the three multiple regression equations are applied to generate 1,225 theoretical datasets. Finally, data envelopment analysis is adopted to find the efficient frontier of the 1,225 theoretical datasets. The found datasets on the efficient frontier are with the optimal quality. The process parameters of the efficient frontier are further validated by Moldflow. This study demonstrates that the developed procedure has proved a useful optimization procedure that can be applied in practice to the injection molding process. پرونده مقاله -
دسترسی آزاد مقاله
4 - Optimizing Rheological Behavior of Steel Feedstocks in Advanced Process of Alloying Powder Injection Molding
حمید خورسند مژده فتحی دوستThe rheological behavior of feedstocks used in powder injection molding technology influences strongly on the final properties of the products. Powder loading is one of the important factors that have a great distribution on rheological behaviors. By using the gas atomi چکیده کاملThe rheological behavior of feedstocks used in powder injection molding technology influences strongly on the final properties of the products. Powder loading is one of the important factors that have a great distribution on rheological behaviors. By using the gas atomized spherical 316L stainless steel powder and the binder of 55% paraffin wax+ 40% polyethylen+ 5% stearic acid, four kinds of feedstocks were prepared at the powder loading of 60, 64, 68 and 72%. To find the proper feedstock and molding temperature, the applied shear rate on the samples has been increased from 100 to 1000 l/s in three different temperatures. The investigations demonstrate that 68% powder loading is the optimal one. This sample shows the minimum sensitivity to shear rate and temperature and in a wide range of temperature has a nearly steady viscosity, consequently demonstrate the best behavior during injection molding. پرونده مقاله -
دسترسی آزاد مقاله
5 - Study on the Effect of Process and Materials on Tensile Strength of the WGRT and Polypropylene Injection Molded Parts
مهدی بزرگی طاهر ازدست عبدالمحمد رضاوندThis study experimentally investigates the effect of processing parameters on mechanical properties of injection molded copolymer. This paper presents an experimental study on the effects of processing parameters including melt temperature, injection pressure and amount چکیده کاملThis study experimentally investigates the effect of processing parameters on mechanical properties of injection molded copolymer. This paper presents an experimental study on the effects of processing parameters including melt temperature, injection pressure and amount preliminary materials on tensile strength of injection molded copolymer PP-WGRT. Polypropylene (PP - supplied by T.P.C of Iran) was used as thermoplastic material. Semi-crystalline material, Maleic anhydride-grafted (MA-g) used as agent cross-linked. Also, melt temperature was changed between 180 to 220 (˚C) and injection pressure was changed between 400 to 800 Bars. The tensile properties of produced parts were measured according to ASTM D 638 – 02. Results showed that tensile strength of copolymer decreases if the amount of WGRT increases. Also, the tensile strength increases by increasing the melting temperature and injection pressure. پرونده مقاله -
دسترسی آزاد مقاله
6 - بررسی اثر میزان تخلخل بر انتقال حرارت در قالبهای تزریق پلاستیک ایجادشده به روش ذوب لیزر انتخابی
سید مصطفی میرطبایی افشین جودکی مرتضی طاهرنیاامکان ساخت هندسه پیچیده کانالهای خنککننده منسجم، با روشهای معمول ماشینکاری مقدور نیست، بنابراین با استفاده از فرآیندهای ساخت افزایشی مانند فرآیند ذوب لیزر انتخابی امکان ایجاد کانالها در قالب فراهم میشود. قطعات ایجاد شده به روش ذوب لیزر انتخابی همواره با تخلخل موا چکیده کاملامکان ساخت هندسه پیچیده کانالهای خنککننده منسجم، با روشهای معمول ماشینکاری مقدور نیست، بنابراین با استفاده از فرآیندهای ساخت افزایشی مانند فرآیند ذوب لیزر انتخابی امکان ایجاد کانالها در قالب فراهم میشود. قطعات ایجاد شده به روش ذوب لیزر انتخابی همواره با تخلخل مواجه هستند،که این مقدار تخلخل وابسته به پارامترهای فرآیند متغیر میباشد، از سوی دیگر توانایی ساخت مواد متخلخل توسط فرآیند ذوب لیزر انتخابی باعث شده است این مواد با توجه به خصوصیاتی نظیر چگالی کمتر و انتقال حرارت بهتر در صنایع هوا فضا، خودرو، مصارف پزشکی و مبدلهای حرارتی نظر محققان را جلب کند و با توجه به این¬که تخلخل علاوه بر تاثیر مستقیم بر روی خواص مکانیکی بر روی انتقال حرارت تاثیر میگذارد. در این پژوهش به بررسی اثر تخلخل بر انتقال حرارت در قالب پرداخته شد، ابتدا مدل و قالب طراحی شده است و بهمنظور بررسی اثر تخلخل چهار مدل شبیهسازی با درصد تخلخلهای حجمی 0، 10، 20و30 در نرمافزار انجام و تحلیل گردید. بررسی و تحلیل نتایج نشان میدهد افزایش درصد تخلخل در قالب سبب افزایش سریعتر دما در قالب میشود. علاوه بر آن با افزایش درصد تخلخل در قالب نرخ کاهش دما در قالب بیشتر میشود و عملیات خنک کاری قطعه سریعتر رخ میدهد. بررسی نتایج بیشینه گرادیان حرارتی ماده بدون تخلخل در مقایسه با ماده 30 درصد تخلخل، افزایش 21درصدی گرادیان حرارتی در ماده متخلخل را نشان داده است. علاوه بر آن بیشینه شار حرارتی ماده بدون تخلخل در مقایسه با ماده 30 درصد تخلخل، کاهش22 درصدی شار حرارتی در ماده متخلخل را نتیجه داده است. پرونده مقاله -
دسترسی آزاد مقاله
7 - An Investigation on the Metal Injection through the Producing of MIM-ed Low-Alloy Steel
S. Rezaei A. AskariIn this study, we demonstrate the injection stage of Metal Injection Molding (MIM) process to fabricate a small bend-type component. This non-standard but critical engine part is made of a feedstock from the low alloy steel 4605. To optimize various injection parameters چکیده کاملIn this study, we demonstrate the injection stage of Metal Injection Molding (MIM) process to fabricate a small bend-type component. This non-standard but critical engine part is made of a feedstock from the low alloy steel 4605. To optimize various injection parameters, the five-variable Box-Behnken Design (BBD) is used with the assumption of a quadratic model, together with the statistical method of Response Surface Methodology (RSM). Samples are then fabricated, and their densities are measured. Hence, the significance of these factors as well as the mutual coupling between each two parameters are investigated using the analysis of variance (ANOVA). Finally, this paper reveals that injection temperature of 155 ◦C, the injection speed of 80 mm/s, holding pressure of 83 bar, holding time of 9 s and the injection pressure of 132 bar led to an optimum density of the green part, which becomes 4.892 g/cm3. Then, a new sample is produced using these optimized settings, and the green component density is measured, which is extremely near to the predicted value. After sintering, the optimized sample’s density and hardness are compared to the MIM-4605 standard criteria. پرونده مقاله
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