復(fù)點(diǎn)機(jī)密封蓋的注射模設(shè)計(jì),機(jī)密,秘要,注射,設(shè)計(jì) 畢業(yè)設(shè)計(jì)(論文)外文資料翻譯 系　　部： 機(jī)械工程系 專(zhuān) 業(yè)： 機(jī)械工程及自動(dòng)化 姓 名： 學(xué) 號(hào)： (用外文寫(xiě)) 外文出處：J.of the Braz. Soc. of Mech. & Eng. July-September 2003, No.3/255 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導(dǎo)教師評(píng)語(yǔ)： 結(jié)合畢業(yè)設(shè)計(jì)課題查找相關(guān)資料，完成翻譯。譯文語(yǔ)句通順，專(zhuān)業(yè)詞匯準(zhǔn)確，編排符合規(guī)范和畢業(yè)設(shè)計(jì)相關(guān)要求。翻譯質(zhì)量?jī)?yōu)。 簽名： 年 月 日 注：請(qǐng)將該封面與附件裝訂成冊(cè)。 附件1：外文資料翻譯譯文 以廢鋁為材料的制動(dòng)盤(pán)和葉輪砂型鑄造 Matthew S. ABOLARIN Oluwafemi A. OLUGBOJI Oladeji A. OGUNWOLE 尼日利亞尼日爾州明那市聯(lián)邦技術(shù)大學(xué)機(jī)械工程系 摘要：葉輪葉片和制動(dòng)盤(pán)是利用砂型鑄造方法生產(chǎn)的。兩種木模以必要余量配合使用。借助環(huán)保技術(shù)和成形方法，并利用當(dāng)?shù)噩F(xiàn)有的材料來(lái)制造模具。鋁廢料也可以作為鑄造材料。利用熔爐熔化鋁廢料，最后將熔融的金屬澆注到砂模內(nèi)，便可以獲得葉輪和制動(dòng)盤(pán)。 在鑄件的清理工作完成之后，所得的兩個(gè)鑄件質(zhì)量良好。根據(jù)鑄件的產(chǎn)量統(tǒng)計(jì)，有73.59％的葉輪葉片和85.1％的制動(dòng)盤(pán)能夠符合要求，這表明這種鑄造方法是可行的。 關(guān)鍵詞：葉輪葉片 制動(dòng)盤(pán) 環(huán)保成型 熔爐 1 導(dǎo)言 制動(dòng)盤(pán)與葉輪 制動(dòng)盤(pán)是一種可以減慢車(chē)輪轉(zhuǎn)速或讓車(chē)輪停止轉(zhuǎn)動(dòng)的裝置。一個(gè)完整的制動(dòng)盤(pán)通常由鑄鐵或如碳、纖維或硅膠等復(fù)合材料制作成的，它的用途是連接車(chē)輪或軸。在制動(dòng)盤(pán)的工作過(guò)程中，是靠摩擦力來(lái)減慢車(chē)輪轉(zhuǎn)速或讓車(chē)輪停止轉(zhuǎn)動(dòng)。因此剎車(chē)皮（安裝在稱(chēng)之為制動(dòng)鉗上的裝置）使用耐摩擦性能較好的材料制成。在液壓、氣動(dòng)或電磁的作用下受到機(jī)械力的作用，并與盤(pán)面產(chǎn)生較大的摩擦力。在摩擦力的作用下可以減慢車(chē)輪轉(zhuǎn)速或讓車(chē)輪停止轉(zhuǎn)動(dòng)。 葉輪一般安裝在管狀裝置內(nèi)，可以增加流體的壓力和提高流體的流量。 水泵葉輪 可旋轉(zhuǎn)的葉輪是離心泵的組成部分，通常是由鑄鐵，鋼，鋁或塑料等材料制成的。由馬達(dá)驅(qū)動(dòng)葉輪旋轉(zhuǎn)，將流體以中心向外以很高的加速度拋出。葉輪工作時(shí)的壓力能轉(zhuǎn)換為流體的動(dòng)能，但是只有在泵套管內(nèi)才存在較大的壓力，從而使流體獲得較大的速度。一般來(lái)說(shuō)，葉輪由一個(gè)較短的通孔（稱(chēng)為眼），流體從一側(cè)流入，從另一側(cè)流出。葉片在徑向方向上給流體施加力，并繞一個(gè)中心軸轉(zhuǎn)動(dòng)。 模具成型 模具成型是一種以與零件外形一致的模型模架為基礎(chǔ)對(duì)工件進(jìn)行生產(chǎn)的過(guò)程。模具有一個(gè)中空的型腔，在它的型腔內(nèi)可以充滿(mǎn)液體，如熔融的塑料、玻璃、金屬或陶瓷材料。液體流入模具內(nèi)并充滿(mǎn)型腔，得到零件的實(shí)際形狀。模具與鑄造的概念并不相同。 鑄造 鑄造是指將熔融的金屬液體注入到模具中，冷卻固化后得到理想形狀零件的成型方法。當(dāng)然，主要的鑄造方法包括：砂型鑄造，在砂型鑄造中將液體倒入一個(gè)由金剛砂料制造的具有一定形狀的模具中；模具鑄件，其中模腔是由經(jīng)過(guò)加工的金屬內(nèi)塊組成；也可用如離心鑄造等方法加工。型砂有一個(gè)相當(dāng)?shù)偷膶?dǎo)熱系數(shù)，可以使砂型中的液態(tài)金屬凝固緩慢，這是由型砂的晶粒粗細(xì)所決定的。當(dāng)然，使用金屬模具也許更合適，可以使零件獲得更細(xì)的晶體結(jié)構(gòu)。 金屬鑄件是現(xiàn)代化的機(jī)器和運(yùn)輸車(chē)輛的重要組成部分。以拖拉機(jī)為例，通過(guò)鑄造得到的金屬零件的比重超過(guò)百分之九十。在汽車(chē)發(fā)動(dòng)機(jī)上，這一比例超過(guò)了百分之五十?？傊?，鑄造提供了一個(gè)改善零件或部件力學(xué)性能的好的方法。以鋁作為材料是因?yàn)殇X在鑄造生產(chǎn)有著良好的機(jī)械性能，比如有著良好的表面粗糙度，重量輕，不易被氧化，塑性較好，具有耐腐蝕性等其他優(yōu)點(diǎn)。本篇論文涉及利用環(huán)保砂模鑄造制動(dòng)盤(pán)和葉輪葉片，其成本并不是太昂貴，其尺寸精度也并不須太精確。由于熔融的鋁合金具有流動(dòng)性和良好的物理特性，因此被廣泛使用。 2 理論分析 砂型鑄造可以用于有色金屬和非有色金屬合金，但特別適用于大噸位的鑄件。有色合金的鑄造中包括鑄鐵和鑄鋼。一般非有色金屬合金鑄造使用的是鋁制的模架，或由銅鎂基合金的模架。合金的溫度范圍控制在450℃至680℃之間。 在熔煉和澆注的過(guò)程中，將金屬熔融的準(zhǔn)備工作是將材料在熔煉爐內(nèi)在適當(dāng)?shù)臏囟认逻M(jìn)行的，之后將熔融的金屬澆注到加工好的模具中。在整個(gè)過(guò)程中，熔化爐的動(dòng)作包括融爐的抬起與融化爐的傾斜。對(duì)于較特殊的鑄造合金，澆注時(shí)的溫度要高于其液體的溫度。超高溫度的選擇是根據(jù)對(duì)金屬的結(jié)構(gòu)和力學(xué)性能的影響決定的，另外還有其他因素，如鑄件的厚度，鑄造金屬的壁厚等。影響模具材料物理性能有溫度和模具材料的初始溫度，及在模具中攪拌鐵水的力等其他因素。鋁合金的澆注溫度一般為680℃-700℃，對(duì)于銅和黃銅材料，溫度一般是在是1000℃-1200℃，鎂合金是在700-800℃，鋼是1520℃-1620℃，鑄鐵則是在1300-1450℃。 3 材料和方法 3.1 材料的使用 直徑為260mm，厚度為15mm的制動(dòng)盤(pán)和直徑為146mm，厚度為5mm的葉輪分別使用以下材料的鑄造：模型材料，模具材料，鋁廢料。 a) 模型材料 利用先進(jìn)的成型繪圖方法可以完成木制模型的虛擬設(shè)計(jì)。硬制木材（如桃花心木）可用于生產(chǎn)葉輪的模型。該葉輪模型從木材最初的尺寸200mm-150mm，考慮到間隔的空間，每個(gè)模型的具體深度可以在繪圖設(shè)計(jì)時(shí)根據(jù)實(shí)際情況修改。 對(duì)于葉輪片盤(pán)，用兩個(gè)32mm32mm見(jiàn)方，每個(gè)厚度在2mm的膠合板釘起來(lái)并粘和在一起。以膠合板邊為對(duì)角線，在其中間開(kāi)一個(gè)半徑為140cm的一個(gè)圓孔。硬木的尺寸為16cm1cm，厚度為3cm，并將它們以膠合板為中心粘釘在一起，并在距離6.7cm處鉆一個(gè)圓孔。油灰可以被用來(lái)填補(bǔ)所有模型的缺陷之處，可修補(bǔ)粗糙的邊緣，在修補(bǔ)工作完成后，將木材刷上漆。 b) 模具材料 該模具為環(huán)保砂模，其中所使用的材料如下：石英砂，黏土和水。組成石英砂的化合物是二氧化硅，也稱(chēng)為硅，是一種硅元素的氧化物，其化學(xué)公式是SiO2。人們自古以來(lái)就已經(jīng)知道它有著很高的硬度。硅最常見(jiàn)的存在形式是砂或石英，以及硅藻的細(xì)胞壁中。大多數(shù)的玻璃和如混凝土這樣的材料的主要組成元素就是硅。二氧化硅是地殼中最豐富的化學(xué)物質(zhì)之一。所使用的砂模工作場(chǎng)合要求是這樣的：在熔融的金屬液注入模具后，型砂仍然要保持潮濕。石英砂的篩選是要獲得晶體顆粒較細(xì)的沙子并去除其他夾雜在沙中的異物。將一定量的沙子與作為粘結(jié)劑的黏土混合。在已經(jīng)混合的混合物中加入水，然后用手徹底地將混合物混合在一起，為制模作好準(zhǔn)備。 鋁 鋁是一種銀白色和具有韌性的一種化學(xué)元素。鋁的符號(hào)是AL；其原子序數(shù)是13。在正常情況下鋁不溶于水。鋁是地球地殼中最豐富的金屬元素之一，排在第三，在它之前的分別是氧和硅。鋁在地殼中的含量大是地球固體表面重量的8％。鋁的化學(xué)性質(zhì)相對(duì)大自然中的其它金屬較為活躍。因此，目前以發(fā)現(xiàn)超過(guò)270種不同的礦物中含有鋁。鋁的主要來(lái)源是鋁土礦。 鋁顯著的化學(xué)性能是它的耐腐蝕性（這是由于鈍化現(xiàn)象所致）和它的低密度。鋁及其合金在航空航天工業(yè)和運(yùn)輸建設(shè)等其他領(lǐng)域發(fā)揮了極其重要的作用。鋁的化學(xué)性質(zhì)使它可作為催化劑或其它化學(xué)添加劑，可運(yùn)用在硝酸銨炸藥的制造上，以曾加硝酸銨炸藥的威力。 熔爐是用于熔化鋁廢料的熔爐又稱(chēng)摩根爐，這是一種使用柴油進(jìn)行燃燒的爐具。 3.2 方法 鋁在熔爐中融化，熔爐是一個(gè)古老而又簡(jiǎn)單的熔化設(shè)備。在金屬融化后倒入其中。在未進(jìn)行熔化處理之前是不能進(jìn)行澆注作業(yè)的。在澆注和凝料完成之后，這兩個(gè)模型將被拆除，清理和進(jìn)行缺陷檢查。 3.3 計(jì)算 葉輪： 葉輪實(shí)際直徑，使用的收縮率，加工余量為。 根據(jù)收縮率得到的模型直徑葉輪直徑（收縮率）（葉輪直徑） 因此，再加上加工余量，這個(gè)模型直徑為： 模型直徑加工余量根據(jù)收縮率得到的模型直徑 制動(dòng)盤(pán)： 實(shí)際葉輪片盤(pán)直徑，收縮率，加工余量。 根據(jù)收縮率得到的模型直徑圓盤(pán)直徑（收縮率）（制動(dòng)盤(pán)直徑） 再加上加工余量，則這個(gè)模型直徑為： 模型直徑＝加工余量＋根據(jù)收縮率得到的模型直徑 鑄件產(chǎn)量——鑄造可以通過(guò)鑄件產(chǎn)量來(lái)計(jì)算，以此確定鑄造中使用金屬的比例。 鑄件產(chǎn)量 其中：鑄件重量，澆注重量，冒口重量。 對(duì)于葉輪而言，鑄件重量，澆注和冒口重量。 鑄件產(chǎn)量 對(duì)于制動(dòng)盤(pán)來(lái)說(shuō)，鑄件重量，澆注和冒口重量 鑄件產(chǎn)量 4 結(jié)果和討論 對(duì)模型進(jìn)行優(yōu)化設(shè)計(jì)時(shí)一些缺陷是可以避免的，當(dāng)然，模具應(yīng)當(dāng)充分的準(zhǔn)備并且在熔煉和澆注的過(guò)程中正確地操作。在這項(xiàng)工作中，由于錯(cuò)誤是不可避免的，因此在葉輪葉片和制動(dòng)盤(pán)的鑄件上會(huì)發(fā)現(xiàn)了一些缺陷。無(wú)論是在鑄件的外部還是內(nèi)部，其表面都相對(duì)比較粗糙。然而，對(duì)外部表面進(jìn)行加工，可以獲得更高的表面粗糙度，就內(nèi)部表面而言，這樣做以改善表面質(zhì)量幾乎是不可能的。在葉輪鑄件中，邊緣一般較粗糙?？梢允褂锰钛a(bǔ)邊緣的方法完善它。 5 結(jié)論 在這項(xiàng)工作中，利用當(dāng)?shù)氐匿X廢料來(lái)生產(chǎn)葉輪和制動(dòng)盤(pán)，并確保它們符合規(guī)范要求。利用砂模制造了兩個(gè)表面粗糙的鑄件，這也可能是由于沒(méi)有添加一些合理的成分，或制造成分比例使用不當(dāng)造成的。兩個(gè)鑄造上所發(fā)現(xiàn)的缺陷可能是由于混入空氣或模具表面光潔度不足，雖然缺陷較小。量葉輪和制動(dòng)盤(pán)的鑄件產(chǎn)量表明，已達(dá)到了良好鑄造效果。 參考文獻(xiàn) [1] Mikhailow A.M.. 金屬鑄造第一版. 莫斯科：Mir出版社, 1989. [2] Howard E.B.，Timothy L.G.. 金屬手冊(cè)Desk版. 美國(guó)：美國(guó)金屬學(xué)會(huì)，1992. 附件2：外文原文 Casting of Brake Disc and Impeller from Aluminium Scrap Using Silica Sand ? Matthew S. ABOLARIN, Oluwafemi A. OLUGBOJI, Oladeji A. OGUNWOLE ? Department of Mechanical Engineering, Federal University of Technology, Minna, Niger State, Nigeria ? Abstract The 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. Keywords Impeller Blade, Brake Disc, Green Moulding, Crucible Furnace, Fettling ? Introduction Break disc and impeller The 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. Molding Molding 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. Casting Casting 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 casting Sand 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 analysis ?Both 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 680°C to 450°C. 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 680°C - 700°C, for bronzes and brasses is 1000 - 1200°C, for magnesium alloy is 700 - 800°C, for steel is 1520 - 1620°C and for cast iron is 1300 - 1450°C. Material and Methods Material used The 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 material A 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 32cm?32cm 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 16cm?16cm?3cm 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 pattern’s sharp and rough edges, after it was filled to a smooth finish. Two coats of wood varnish were applied.? Mould material The 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 earth's 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. Aluminium Aluminium 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 Earth's crust, and the third most abundant element therein, after oxygen and silicon. It makes up about 8% by weight of the Earth’s 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. Furnace The furnace used for the melting of the aluminium scrap is the Morgan furnace, which makes use of diesel oil for burning. Methods Aluminium 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. Calculations Impeller Actual 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+ (13?146/1000) = 146 + 1898/1000 = 146 + 1.898 = 147.898mm. Therefore, adding machining allowance, this diameter of the pattern becomes Diameter of the pattern = Machine allowance + Diameter of pattern due to shrinkage = 6 + 147.898 = 153.898mm. Brake disc Actual 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 disc Diameter) = 260 + (13?260/1000) = 260 +3380/1000 = 260 + 3.38 = 263.38mm Adding machining allowance, thus diameter of the pattern becomes Diameter of the pattern = Machine allowance + Diameter of pattern due to shrinkage = 263.38+6 = 269.38 = 269 mm Casting 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 = 2.0Kg Weight of gating and riser = 0.35Kg Casting Yield ?? = 2.0/(2.0+0.35) = 2/2.35 = 0.851 ? 100= 85.1% Result and Discussion A 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. Conclusion In 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. ? References [1] 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.