فهرست مطالب
Journal of Modern Processes in Manufacturing and Production
Volume:2 Issue: 4, 2014
- تاریخ انتشار: 1392/10/15
- تعداد عناوین: 6
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صفحات 3-12برنامه ریزی تولید، بسته به سیستم تولیدی انتخاب شده برای واحد تولیدی، روش های مختلفی را به خود اختصاص می دهد. یکی از اقدامات مهم که بایستی پیش از برنامه ریزی تولید صورت پذیرد، تعیین سیستم تولید و متعاقبا چیدمان مطلوب ماشین آلات آن واحد است. سیستم های تولید کارگاهی و تکنولوژی گروهی، هر یک دارای مزایا و معایب مخصوص به خود است. در این میان سنجش عملکرد واحد هم به لحاظ معیارهای بهره وری و هم از نظر معیارهای صفی، در قالب سیستم های متنوع، امری خطیر محسوب می شود. از این رو، روش های متعددی برای این سنجش عملکرد ارائه شده است. یکی از این روش ها، شبیه سازی واحد تولیدی در رایانه و اجرای فرضی آن در قالب سیستم مدنظر است. در این مقاله، با استفاده از نرم افزار ARENA، سیستم های تولید کارگاهی و تکنولوژی گروهی برای یک واحد تولیدی خاص، به طور مجزا، شبیه سازی، اجرا و مقایسه شده اند. نتایج حاصل، حاکی از آن هستند که سیستم تکنولوژی گروهی در مثال مدنظر هم از نظر شاخص های بهره وری و هم از نظر شاخص های صفی، عملکرد بهتری نسبت به سیستم تولید کارگاهی از خود به جای گذاشته و تغییر سیستم کنونی کارگاه توصیه می شود.کلیدواژگان: طراحی سیستم تولید، تولید کارگاهی، تکنولوژی گروهی، شبیه سازی
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صفحات 39-44بابیت آلیاژی است سفید و نقره فام که از فلزات قلع، سرب ، مس و آنتیموان تشکیل شده است که رایج ترین آلیاژ یاتاقانی در کاربردهای صنعتی است. ویژگی هایی نظیر مقاومت سایشی بالا و ضریب اصطکاک پایین آلیاژ بابیت را به پوشش یاتاقانی تبدیل کرده است. هدف این پژوهش بررسی اثرات عناصر آلیاژی بر روی خواص سایشی و میکروساختاری پوشش بابیت است. بدین منظور 3 گروه آلیاژ بابیت با درصد عناصر متفاوت تهیه شده است. جهت بررسی خواص سایشی تست سایش خشک به روش پین روی دیسک انجام گرفته و سطوح سایش توسط میکروسکوپ الکترونی روبشی مشاهده و بررسی شده اند. نمونه ها همچنین از نظرسختی با یکدیگر مقایسه شده اند. مطالعات متالوگرافی و نتایج حاصل از آزمایش ها نشان می دهد که اندازه و شکل ذرات و نحوه توزیع آن ها مهم ترین عاملی است که بر خواص مکانیکی و همچنین خواص اصطکاکی آلیاژ بابیت تاثیرگذار است؛ بنابراین می توان گفت کنترل میکروساختار آلیاژ بابیت از نظر تشکیل فازها و ایجاد رسوبات باعث می شود خواص مطلوب و درخور انتظار از آلیاژ بابیت به عنوان آلیاژ مقاوم در برابر سایش برآورده شود.کلیدواژگان: آلیاژ بابیت، سایش، میکروساختار، ضریب اصطکاک، پین روی دیسک، میکروسکوپ الکترونی روبشی
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Pages 3-12Production planning is performed through diverse methods according to the type of the system it is structured upon. One of the most important steps before production planning is to determine which system best fits the firm, and how the facilities should be designed. Both job-shop and group-technology systems have their own cons and pros, each of which is suitable to a specific kind of factory. On the other hand, performance measurement is also important in terms of both productivity and queue factors. A good method to measure the performance is computer simulation by software such as ARENA. This paper utilizes the software for simulating both job-shop and group-technology systems separately for a special firm and it consequently compares the results. The results show group-technology system is better than job-shop system in both productivity and queue factors, and it is highly recommended the system be changed.Keywords: Production System Design, Job Shop, Group Technology, Simulation
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Pages 13-20With many years of construction and application of common concrete, researchers have always been searching for a better composition. One of the notable ideas for achieving such a composition is using recycled materials. One of the materials which is suitable for environment and constant development is damaged tires .For studying mechanical properties of concrete containing tire particles, a series of experimental studies undertaken. In this study, a mix design with 28-day compressive strength of 40 MPa was considered. Then by replacing 10 percent (by weight) of sand with tire particles (without changing other parameters), the required test was done for determination of compressive and tensile strength of concrete samples. By application of microsilica, its effect on mechanical properties of concrete samples were studied. The obtained results from tests are demonstrated by graphs and tables. By considering the environment in this research ,it has been dealt with mechanical properties of concrete containing rubber particeles toward constant development.Keywords: Concrete, Mix design, Compressive strength, Tension strength, Tire rubber particles, Microsilica
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Pages 21-28Cold rolling process of a major transformation in the form of sheet metal and a wide range of steel products are produced in this way. Elastic deformation during cold rolling working rollers and the inevitable increase in the rolling force. In this study, the effect of elastic deformation during cold rolling mill rollers working on the reciprocating back and forth in tandem with the presence of tensile stresses two cages will be discussed. In this system, rolling, sheet by passing between two shelves inreciprocating motion to achieve the desired final thickness (almost three passes reciprocating 2 shelves). One of the most important factors during the cold rolling process, determine the force and pressure rolling. By writing equations deformed sheet Slab Method software MATLAB, as well as a passer by reciprocating rolling process simulation software ABAQUS, force and pressure of the rolling mill for the entire process and shelves, with or without the effects of disruption flat work rollers were calculated. Finally three different passes into the shelf rolled on a coil of cold rolled steel products took place. The results showed a sharp increase in the working rollers are rolling in the flat disruption.Keywords: Simulation, Elastic deformation, Cold rolling
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Pages 29-38Electromagnetic forming is a high energy rate forming process. In this process, an electromagnetic Lorentz body force is used for deformation of products. In this article, Electromagnetic forming process was simulated for assembly of parts as an innovative method. In this research work, the effect of important parameters of process such as discharge energy, radius and width of rectangular groove on the strength of assembled products were studied by using finite element technique and design of experiment. After introducing the governing equations, the output of these equations were applied in simulation as a pressure on work-piece. In this simulation, an axisymmetric model was used in analysis and Johnson-Cook theory was applied due to high strain rate to show the plastic behavior of materials. Finally, the numerical results were compared with the experimental results reported by other researchers and found a good correlation between them. As a result, the bead depth increases with the increase of the discharge energy and more filling groove, increasing strength of joint. In addition, Strength of joint increases, due to create partial shearing of the tube at the groove edge and interference stresses at the tube and mandrel interface.Keywords: Electromagnetic Forming, Finite Element, Groove, Aluminum tube, strength of joint
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Pages 39-44Babbitt is a white silvery alloy that composed of Tin, Lead, Copper and Antimony. This alloy is the most current bearing alloy in industrial applications. The characteristics of this alloy, such as high wearing resistance and low coefficient of friction, have converted it into a bearing cover. The target of this study is investigation on the effects of alloy elements on wearing and micro-structural properties of the Babbitt cover. To this end, 3 groups of Babbitt alloy with different percent of elements were provided. In order to survey wearing properties, the dry wearing test with Pin on disc was done. The wearing surfaces by Sweep Electron Microscope was observed and investigated. Also, the samples were compared to each other. The metallography studies and the results of experiments show that the size, the shape of particles and how to distribution of them are most important factors which effect on mechanical properties and also frictional properties of Babbitt alloy. Therefore, it may be said the control of microstructures in Babbitt alloy because of formation of the phases and creation of the sediments causes the desirable and expected properties in Babbitt alloy as a resistant alloy against wearing.Keywords: Babbitt Alloy, Abrasion, Micro structure, Coefficient of Friction, Pin, on, disk, SEM
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Pages 45-50Porous NiTi alloys has a series of unique properties such as shape memory effect, superelastic behavior and energy absorbability that make them usable in a wide range of medical and industrial appliances. But the more probability of Ni release from a porous NiTi compare to the nonporous one has restricted its uses in implants. In the present research for resolving the problem, performing a calcium-phosphate layer on an Iranian porous alloy was considered. For this purpose all of the samples were immersed in SBF for 3 and 5 days. Some of them passed the dipping in SBF stage after 30% HNO3 and 1.2 M NaOH solution treatments. All the samples were characterized using SEM equipped with EDS and light microscopy. The results show that the chemical treated samples had better and more uniform calcium-phosphate layer forming ability than the untreated ones. The obtained results could be used in orthopedic applications.