2670 复点机密封盖的注射模设计

2670 复点机密封盖的注射模设计,机密,秘要,注射,设计 Casting of Brake Disc and Impeller from Aluminium Scrap Using Silica SandMatthew S. ABOLARIN, Oluwafemi A. OLUGBOJI, Oladeji A. OGUNWOLEDepartment of Mechanical Engineering, Federal University of Technology, Minna, Niger State, NigeriaAbstractThe impeller blade and the brake disc were produced using sand casting method. Wooden patterns of the two castings were constructed incorporating the necessary allowances. Green and moulding technique utilizing locally available materials were used for preparing the moulds. Aluminium scraps were used as the casting material. Melting of the Aluminium scraps was obtained using a crucible furnace and finally pouring the molten metal into the sand mould to obtain the impeller and the brake disc.After fettling and cleaning, the two casting were found to be good. The casting yield was found to be 73.59% for the impeller blade and 85.1% for the brake disc which indicate that sound casting was achieved.KeywordsImpeller Blade, Brake Disc, Green Moulding, Crucible Furnace, FettlingIntroductionBreak disc and impellerThe brake disc is a device for slowing or stopping the rotation of a wheel. A brake disc, usually made of cast iron or ceramic composites (including carbon, kevlar and silica), is connected to the wheel or the axle. To stop the wheel, friction material in the form of brake pads (mounted on a device called a brake caliper) is forced mechanically, hydraulically, pneumatically or electromagnetically against both sides of the disc. Friction causes the disc and attached wheel to slow or stop.An impeller is a rotor inside a tube or conduit to increase the pressure and flow of a fluid.Impellers in pumps. An impeller is a rotating component of a centrifugal pump, usually made of iron, steel, aluminum or plastic, which transfers energy from the motor that drives the pump to the fluid being pumped by accelerating the fluid outwards from the center of rotation. The velocity achieved by the impeller transfers into pressure when the outward movement of the fluid is confined by the pump casing. Impellers are usually short cylinders with an open inlet (called an eye) to accept incoming fluid, vanes to push the fluid radially, and a splined center to accept a driveshaft.MoldingMolding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern.A mold is a hollowed-out block that is filled with a liquid like plastic, glass, metal, or ceramic raw materials. The liquid hardens or sets inside the mold, adopting its shape. A mold is the opposite of a cast. CastingCasting refers to the pouring of the molten metal into a mould, in which it cools and solidifies to produce an object of desired shape. However, the main casting methods available include: sand casting, in which liquid is poured into a shape cavity moulded from sand; die casting, in which the mould cavity is machined within metal die block; investment and centrifugal casting also exist. Moulding sand has a fairly low thermal conductivity so that the rate of solidification of liquid metal with a sand mould is fairly slow, given rise to a coarse crystal grain size. This of course makes the use of metallic mould more suitable in order to obtain a fine grain structure.Sand castingSand casting is one of the most popular and simplest types of casting that has been used for centuries. Sand casting allows for smaller batches to be made compared to permanent mold casting and at a very reasonable cost. Not only does this method allow manufacturers to create products at a low cost, but there are other benefits to sand casting, such as very small size operations. From castings that fit in the palm of your hand to train beds. one casting can create the entire bed for one rail car, it can all be done with sand casting. Sand casting also allows most metals to be cast depending on the type of sand used for the molds.Metal castings are vital components of most modern machines and transportation vehicles. Cast metals parts accounts for more than ninety percent of the weight of tractor and more than fifty percent of an automobile engine. Above all, casting provides a process of improving the mechanical properties of components or articles. Aluminium is used because it produces casting of good mechanical properties, such as good surface finish, light weight, fewer tendencies to oxidation, lending to modification, resistance to corrosion and its availability. This work covers the casting of brake disc and impeller blade using a properly prepared green sand mould, which is less expensive and gives less distortion and dimensional accuracy. Aluminum alloy is used because of its fluidity and good physical properties.Theoretical analysisBoth ferrous and non - ferrous alloys can be cast using green sand method especially when greater tonnage of casting is required. The ferrous alloys cast by this process include cast iron and steel. The commonly non - ferrous alloys cast by this process are aluminum base, copper base and magnesium base alloys. The temperature of these alloys ranges from 680C to 450C.Melting and pouring are processes of preparing molten metal of the proper composition and temperature in foundary using appropriate melting furnace and pouring the prepared molten metal into the mould from transfer ladles. Furnace melting alloys in the foundry include lift out or tilting crucible furnace. For a particular casting alloy, the temperature of pouring is taken with a certain super heat above its liquids temperature. The super heat is chosen depending on the influence of super heat temperature on the structure and mechanical properties of metal, the thickness and extensions of the walls of casting, the liability of the metals to form films, the thermo - physical properties of the mould material and the initial temperature of the mould material, the forces that cause stirring of hot metal in the mould and other factors. The pouring temperature for aluminium alloy is 680C - 700C, for bronzes and brasses is 1000 - 1200C, for magnesium alloy is 700 - 800C, for steel is 1520 - 1620C and for cast iron is 1300 - 1450C.Material and MethodsMaterial usedThe brake disc of 260mm diameter and 15mm thickness and the impeller of 146mm diameter and 5mm thickness respectively were cast with the following materials: pattern material, mould material, aluminium scrap, and furnace.Pattern materialA wooden pattern was produced from the developed pattern drawing. A hard wood (mahogany) was use for the production of the impeller pattern. The pattern for the impeller was produced from the wood of initial dimension 200mm 150mm, putting into consideration the spacing of the characters, depth of each shape using the specified dimension on the patter drawing.In the case of the blade disc, two plywoods, each 2cm thick of 32cm32cm were glued and nailed together. A divider opened to a radius of 14cm was used to inscribe a circle in its centre, found by drawing diagonals from the plywood edges. Hardwood of 16cm16cm3cm was glued and nailed to the centre of the plywood, and a divider opened to 6.7cm was used to inscribe a circle for the bore to be drilled. Putty was used to fill all chipped imperfections and also in filleting the patterns sharp and rough edges, after it was filled to a smooth finish. Two coats of wood varnish were applied. Mould materialThe mould materials used is the green sand mould and they include the following: silica sand, bentonite, and water. The chemical compound silicon dioxide, also known as silica, is an oxide of silicon with a chemical formula of SiO2 and has been known for its hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms. It is a principal component of most types of glass and substances such as concrete. Silica is the most abundant mineral in the earths crust. Green sand moulding which was used is a situation where the moulding sand remained moist until the metal is poured into it. Silica sand was sieved to obtain fine grain sized sand and to remove other foreign bodies in the sand. A specific quantity of the sand was fetched and bentonite was added as binder and mixed thoroughly with the sand. Water was then added to the already mixed mixtures, which were then thoroughly mixed together by hand to make ready for mould.AluminiumAluminium is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances. Aluminium is the most abundant metal in the Earths crust, and the third most abundant element therein, after oxygen and silicon. It makes up about 8% by weight of the Earths solid surface. Aluminium is too reactive chemically to occur in nature as the free metal. Instead, it is found combined in over 270 different minerals. The chief source of aluminium is bauxite ore.Aluminium is remarkable for its ability to resist corrosion due to the phenomenon of passivation and its low density. Structural components made from aluminium and its alloys are vital to the aerospace industry and very important in other areas of transportation and building. Its reactive nature makes it useful as a catalyst or additive in chemical mixtures, including being used in ammonium nitrate explosives to enhance blast power.FurnaceThe furnace used for the melting of the aluminium scrap is the Morgan furnace, which makes use of diesel oil for burning.MethodsAluminium was melted in a crucible furnace, an oldest and simple type of melting equipment. It was poured after melting into the mould earlier prepared for the two patterns. No melting treatment was carried out prior to pouring operation. After the pouring and solidification is completed, the two patterns were removed, cleaned and inspected for possible defects.CalculationsImpellerActual impeller diameter = 146mm, Shrinkage allowance used = 13mm/m, Machining allowance used 6mm.Diameter of pattern due to shrinkage = Impeller Diameter + (Shrinkage Allowance) (Impeller Diameter) = 146+ (13146/1000) = 146 + 1898/1000 = 146 + 1.898 = 147.898mm.Therefore, adding machining allowance, this diameter of the pattern becomesDiameter of the pattern = Machine allowance + Diameter of pattern due to shrinkage = 6 + 147.898 = 153.898mm.Brake discActual blade disc diameter = 260mm, Shrinkage allowance used = 13mm/m, Machining allowance used = 6mm.Diameter of the pattern due to shrinkage = Disc diameter + (Shrinkage allowance) (Brake discDiameter) = 260 + (13260/1000) = 260 +3380/1000 = 260 + 3.38 = 263.38mmAdding machining allowance, thus diameter of the pattern becomesDiameter of the pattern = Machine allowance + Diameter of pattern due to shrinkage= 263.38+6 = 269.38 = 269 mmCasting Yields - The casting can be evaluated using casting yield, which determines the percentage use of metal in casting.Casting Yield = WC/(WC + WG+WR)Where WC = Casting Weight, WG = Gating Weight, WR = Riser Weight.For the impeller,Casting Weight, WC = 0.418Kg.Weight of gating and riser, WG + WR = 0.15Kg.Casting Yield = 0.418/(0.418+0.15) = 0.418/0.568 = 0.7359 100 = 73.59%For the brake disc,Casting Weight = WC = 2.0KgWeight of gating and riser = 0.35KgCasting Yield = 2.0/(2.0+0.35) = 2/2.35 = 0.851 100= 85.1%Result and DiscussionA casting free of defects can be obtained if the pattern is properly designed, the mould properly prepared and the melting and pouring processes correctly carried out. In this work, due to unavoidable errors, some defects were noticed on the cast impeller blade and the brake disc. Both the external and the internal surface of the casting were relatively rough compared with the degree of smoothness expected of the brake disc. However, the external surface was machined to obtain a higher degree of smoothness while for internal surface; there was little or nothing which could be done to improve the smoothness. In the case of cast impeller, it was only the edge that was rough. A file was use used in filling the edges in order to smoothen it.ConclusionIn the course of this work, effort was made to produce locally the impeller and brake disc from aluminum scraps and to ensure that they conform to specification required. The green sand mould prepared gave the rough surface of the two castings, this may be due to the fact that no additives were added or proper percentage composition was not used. The defects found on the two casting may be due to entrapped air and poor surface finish of the mould, though the defects are minor. The cast yield for the impeller and the brake disc indicates that sound casting was achieved.References1 Mikhailow A. M., Metal Casting, First edition Mir Publishers, Moscow, 1989.2 Howard E. B., Timothy L. G., Metal Handbook, Desk edition, America Society for Metal (ASM) USA, 1992.南京理工大学泰州科技学院学生毕业设计（论文）中期检查表学生姓名 刘养韬 学 号 05010126 指导教师 殷劲松课题名称 复点机密封盖的注射模设计难易程度 偏难 适中 偏易选题情况工作量 较大 合理 较小任务书 有 无开题报告 有 无符合规范化 的要求外文翻译质量 优 良 中 差学习态度、出勤情况 好 一般 差工作进度 快 按计划进行 慢中期工作汇报及解答问题情况优 良 中 差中期成绩评定：优所在专业意见：负责人： 年 月 日 南京理工大学泰州科技学院毕业设计（论文）任务书系 部 ： 机械工程系专 业 ： 机械工程及自动化学 生 姓 名： 刘养韬学 号：05010126设计 (论文 )题目 ： 复点机密封盖的注射模设计起 迄 日 期 : 2009 年 3 月 9 日 2009 年 6 月 14 日设计 (论文 )地点 : 南京理工大学泰州科技学院指 导 教 师 : 殷劲松专 业 负 责 人 : 龚光容发任务书日期: 2009 年 2 月 26 日任务书填写要求1毕业设计（论文）任务书由指导教师根据各课题的具体情况填写，经学生所在专业的负责人审查、系部领导签字后生效。此任务书应在第七学期结束前填好并发给学生；2任务书内容必须用黑墨水笔工整书写或按教务处统一设计的电子文档标准格式（可从教务处网页上下载）打印，不得随便涂改或潦草书写，禁止打印在其它纸上后剪贴；3任务书内填写的内容，必须和学生毕业设计（论文）完成的情况相一致，若有变更，应当经过所在专业及系部主管领导审批后方可重新填写；4任务书内有关“系部” 、 “专业”等名称的填写，应写中文全称，不能写数字代码。学生的“学号”要写全号；5任务书内“主要参考文献”的填写，应按照国标 GB 77142005文后参考文献著录规则的要求书写，不能有随意性；6有关年月日等日期的填写，应当按照国标 GB/T 74082005数据元和交换格式、信息交换、日期和时间表示法规定的要求，一律用阿拉伯数字书写。如“2008 年 3 月 15 日”或“2008-03-15”。毕 业 设 计（论 文）任 务 书1本毕业设计（论文）课题应达到的目的：塑料件在各行业及日常生活广泛使用，塑料模具的设计制造的社会需求也日益增长，而且要求越来越高。通过对吹风机头的注射模设计，培养学生检索资料，综合应用所学知识，并根据工程实际的要求解决工程实际问题的方法与能力，训练学生模具设计制造的基本技能和模具 CAD 设计能力，提高独立工作的能力，适应社会需求。2本毕业设计（论文）课题任务的内容和要求（包括原始数据、技术要求、工作要求等）：本课题的任务内容是要求设计一副带侧抽芯机构的注射模，以此为基础，完成模具制造的工艺设计。课题工作量较大，难度适中。具体内容包括： （1）调查研究、查阅及翻译文献资料，撰写开题报告；（2）根据模具结构要求进行塑件设计；（3）模具总体方案论证（至少设计 3 个方案） ；（4）模具装配图及全部零件图；（5）模具制造工艺；（6）文档整理、撰写毕业设计说明书及使用说明书。对模具的要求：（1）顺序开模（2）动力利用开模动作（3）自动脱凝料（4）一模二件毕 业 设 计（论 文）任 务 书3对本毕业设计（论文）课题成果的要求包括毕业设计论文、图表、实物样品等：（1）开题报告、文献综述、资料翻译；（2）模具总体方案图（至少 3 个） ；（3）模具装配图及全部零件图；（4）模具制造工艺文件；（5）毕业设计说明书。 4主要参考文献：1 成都科技大学等.塑料成型模具M.北京：中国轻工业出版社，1982. 2 西德H.盖斯特罗编著,王文展译.注射模设计 102 例M. 北京：国防工业出版社，1990.3 日叶屋臣一等,许鹤峰等译.注射模具设计和应用M. 北京：轻工业出版社，1989.4 成都科技大学.塑料成型工艺学M. 北京：轻工业出版社，1989.5塑料模具设计手册编写组. 塑料模具设计手册S. 北京：机械工业出版社,1982.6机械设计手册联合编写组. 机械设计手册S. 第 2 版，北京：机械工业出版社,1987.7 成都科技大学，北京化工学院，天津轻工业学院合编.塑料成型模具M.北京：中国轻工业出版社，1982.8 胡石玉.模具制造技术M.南京：东南大学出版社，1997.9 骆志斌.模具工手册M.南京：江苏科学技术出版社，2000.10 林清安.Pro/ENGINEER 零件设计（基础篇上、下）M.北京：北京大学出版社，2000.毕 业 设 计（论 文）任 务 书5本毕业设计（论文）课题工作进度计划：起 迄 日 期 工 作 内 容2009 年3 月 09 日 3 月 30 日3 月 31 日 4 月 07 日4 月 08 日 4 月 15 日4 月 16 日 4 月 23 日4 月 24 日 5 月 15 日5 月 16 日 5 月 23 日5 月 24 日 6 月 07 日6 月 07 日 6 月 10 日6 月 11 日 6 月 14 日接受毕业设计任务，熟悉毕业设计要求。查阅资料，完成外文资料翻译工作撰写开题报告及文献综述按照模具结构要求进行塑件设计，进行模具初步方案考虑。模具总体方案论证：画出模具总体方案图（至少 3 个） ，优选一种（应有文字说明） 。同时熟悉 CAD 软件。模具装配图和全部零件图制定模具制造工艺文件文档整理、撰写毕业设计说明书。提交毕业设计成果准备论文答辩所在专业审查意见：负责人： 年 月 日学院（系）意见：院（系）领导： 年 月 日