模具設(shè)計(jì)外文翻譯---塑料成型過(guò)程

1、<p><b>　　外文翻譯原文 </b></p><p>　　Plastics forming processes</p><p>　　There is a wide range of processing methods that may be used for plastics. Nevertheless, they all involve three

2、 or four basic stages: softening, shaping, solidifying and cooling of the moulds (for thermoplastics only). Common materials for moulding processes are thermoplastics and thermoset polymers. Principal methods of processi

3、ng thermoplastics include extols ion, blow moulding, rotational moulding, thermoforming and injection moulding; but as for thermosets, compression, transfer and reaction</p><p>　　1 Extrusion</p><

4、p>　　Extrusion is one of the most important forming processes for the reason that pellets, which are used for many other moulding processes, are normally produced by this process. In fact, some moulding processes are p

5、ost-extrusion operations, such as blow moulding and thermoform moulding. Extnlsion is basically a process of continuously shaping a fluid polymer through the orifice of a die, and subsequently solidifying it into a produ

6、ct of a uniform cross-section. An extruding machine may have one or</p><p>　　FIGURE 1.Single-screw extruder.</p><p>　　2 Blow moulding</p><p>　　This process begins with the preparat

7、ion of a soft, extruded and preformed thermoplastic tube over a core pin.As the mould halves close, air pressure inflates the thinwalled preform and forces it outwards against the mould sides. Figure 2 shows the process

8、at two stages. The preform can be made by either extras ion or injection. Blow moulds are subjected to moderate pressures and clamping forces, compared to injection moulds. Thus, they can be made of a light material such

9、 as aluminmm, which has</p><p>　　Blown-ware containers are commonly used for packaging beverage and other fluid food, e.g. narrow neck plastic bottles for mineral water, milk, alcoholic beverage and carbonat

10、ed beverages. Other non-food products packed in the blown-ware containers include cosmetics, pharmaceuticals, paint and powder products. Blow moulding is also used to produce some huge products in size, such as shipping

11、drums and stationary storage tanks whose volumes may reach as high as 10 000 litres [5]. These tanks are u</p><p>　　Stage 1: Preform extrusion Stage 2: Blowing</p><p>　　FIGURE 2.Extrusion bl

12、ow moulding</p><p>　　3 Rotational moulding</p><p>　　Like blow moulding, rotational moulding is also used to produce hollow plastic articles, though the principles in each method differ a lot. D

13、uring the process, a carefully weighed charge of plastic powder is placed in one half of a metal mould. The mould halves are then clamped together and heated on an oven. When heated, the mould rotates about two axes at r

14、ight angles to each other. After a time the plastics will be sufficiently softened to form a homogeneous layer on the surface of the mould.</p><p>　　FIGURE 3.Shuttle cart rotational moulding.</p><

15、p>　　The Institution of Professional Engineers New Zealand</p><p>　　4 Compression moulding</p><p>　　Compression moulding is often used to produce articles from thermoset materials, though it

16、can also be used for thermoplastics. The moulding operation used for thermosets is illustrated in Figure 4. A large number of compression moulded thermoset products can be found in electrical and electronic applications.

17、 Glass-fibre reinforcement can be easily added to meet the heat resistance requirement. However, the limitation with this process is that the product has to be simple in shape and without t</p><p>　　FIGURE 4

18、.Compression moulding.</p><p>　　5 Transfer moulding</p><p>　　Transfer moulding is similar to compression moulding except that, instead of the moulding material being pressurised in the cavity,

19、it is pressurised in a separate chamber and then forced through an opening and into a closed mould cavity. The advantage of transfer moulding is that the preheating of the material injected through a narrow orifice impro

20、ves the temperature distribution in the material and hence accelerates the cross-linking reaction in thermosets. As a result the cycle time is reduc</p><p>　　6 Thermoforming</p><p>　　Sheet ther

21、moforming was developed in the 1950s. The limitations such as poor wall thickness distribution and large peripheral waste restricted its use to simple packaging applications. In recent years, however, there have been maj

22、or advances in machine design and materials, which have resulted in a wide range of products being made by thermoforming. There are three types of thermoforming processes (Figure 5): vacuum moulding, air pressure mouldin

23、g, and mechanical moulding.</p><p>　　The moulds, which are not subjected to high pressure, are often made from cast or machined alumininm for small and medium sizes, and they do not require a good surface fi

24、nish. The product surface quality is largely dependent upon that of the sheet material.</p><p>　　Products made by thermoforming can be small as well as large. Smaller products are made in high output machine

25、s, using multi-cavity moulds. Such products are often found in the food industry and medical applications, for example, jelly or cream containers, cups, robs and trays. These small items can have relatively complex shape

26、s with reasonably even thickness. Large products are generally made from cut sheets at a lower though-put rate, and they are usually of simple shapes. Fisher & Paykel's v</p><p>　　FIGURE 5.Three basi

27、c methods of thermoforming.</p><p>　　7 Injection moulding</p><p>　　Injection moulding has always been one of the most common processing methods for plastics. Nowadays countless parts in many el

28、ectrical appliances, automobiles and office equipment are injection moulded. The most common injection moulding machinery is the reciprocating screw machine, whose process can be divided into several stages as seen in Fi

29、gure 6. At the plastication stage, the feed unit operates as an extntder, melting and homogenising the material in the screw/barrel system. The screw, how</p><p>　　Although the screw machine is by far the mo

30、st popular, plunger injection machines are also used to give products some unique features. There is no shearing or mixing action, as a plunger does not rotate. The resulting moulded part can take on a marbled appearance

31、 with swirls of two or more colours. This may be the desired finish for certain products. Regardless of different machines, injection moulding yields a high productivity and allows the products to have many fine details

32、such as bosses, l</p><p>　　A large variety of products can be injection moulded. These include (a) micro-products, moulded in multiple cavity moulds on small precision machines, such as components for watche

33、s and microelectronics; (b) medium size products, moulded continuously in very large numbers in dedicated machines or in relatively small runs; and (c) large products, moulded by large machines, such as car dashboard fra

34、mes, TV cabinets, garden furniture, and small boat hulls. Many of these large plastic parts have a s</p><p>　　FIGURE 6. Sequence of operations in injection moulding.</p><p>　　8 Reaction injecti

35、on moulding</p><p>　　Reaction injection moulding is a relatively new process, which involves the rapid mixing, in precise proportions, of two or more highly reactive liquid components and the immediate injec

36、tion of the mixture in a closed mould Polymerisation takes place in the mould in a very short period of time, yielding a solid product. The process is particularly suited to the production of large and relatively thin pa

37、rts, with less capital investment and operating costs than in thermoplastic injection moulding</p><p>　　9 Conclusions</p><p>　　By and large, each moulding process mentioned above has its pros a

38、nd cons in terms of the materials, products and cost. The plastics industry plays an important role in today's manufacturing industry. Plastics moulding is the most popular process. Whereas injection moulding continu

39、es to dominate the sector, other moulding processes make some important contributions toward manufacture of many specific products. Faced by numerous challenges, new processes are making their way into the market. Cons&l

40、t;/p><p><b>　　外文翻譯譯文 </b></p><p><b>　　塑料成型過(guò)程</b></p><p>　　有很多關(guān)于塑料成型的方法。盡管如此，它們都包跨三個(gè)或者四個(gè)基本環(huán)節(jié)：軟化、修整、凝固、模具冷卻（僅適用于熱塑性模具）。一般的對(duì)于模具成型過(guò)程的材料是熱塑性和熱固性的聚合體。主要的處理熱塑性塑料的方法包括等

41、離子法、吹鑄法、旋轉(zhuǎn)鑄法、加熱成形法、注塑模法，但是關(guān)于熱固性塑料，壓縮法、轉(zhuǎn)移法和反推注塑法常常被使用。</p><p><b>　　1 擠壓法</b></p><p>　　擠壓法是最重要的成形方法之一因?yàn)橛米髟S多其它的模制過(guò)程的小球很普遍地在這個(gè)過(guò)程中被引長(zhǎng)。事實(shí)上，一些模制方法是一些加速擠壓的操作，如吹模法和加熱成形模制法。擠壓法是一個(gè)通過(guò)模具孔和后來(lái)把它固化

42、為的一個(gè)統(tǒng)一的橫截面的不斷修正流動(dòng)聚合體的基本過(guò)程。一個(gè)擠壓機(jī)擁有一個(gè)或者兩個(gè)螺桿，或者沒(méi)有螺桿（無(wú)螺桿型）。單一螺桿擠壓機(jī)，正如圖形1所示，是最通常使用的機(jī)器。無(wú)螺桿型（撞錘型）擠壓機(jī)通常流行為開(kāi)槽型并且允許對(duì)熔體流動(dòng)率的精確控制。他們特別適合高粘度的場(chǎng)合。近些年，對(duì)雙螺桿擠壓機(jī)的應(yīng)用已經(jīng)有了穩(wěn)定的增長(zhǎng)。這些機(jī)器根據(jù)產(chǎn)出率、混合效率、生熱性允許一個(gè)寬的可能性范圍。盡管如此他們相比較而言更加的貴。普通的擠壓產(chǎn)品包括圓形橫截面的細(xì)絲、不規(guī)

43、則橫截面的側(cè)面、軸對(duì)稱的管子、和諸如薄片或者薄膜之類的扁平軋材。幾乎所有有很大尺寸的復(fù)雜的代表性形狀都是用擠壓模制做成的，許多是其它單獨(dú)的成型過(guò)程，諸如壓制、移動(dòng)和注塑成形難以生產(chǎn)的。</p><p>　　圖片1.單絲杠擠壓機(jī)</p><p><b>　　2 吹鑄成型</b></p><p>　　這個(gè)過(guò)程從準(zhǔn)備一個(gè)軟的被擠壓了并且預(yù)成型的壓在

44、中心梢上的熱塑料性軟管開(kāi)始。當(dāng)模具關(guān)攏時(shí)，空氣壓力會(huì)使得薄壁的成型腔膨脹并使它向外地?cái)U(kuò)張模具面。圖片2展現(xiàn)了這兩個(gè)時(shí)期的過(guò)程。這個(gè)預(yù)先變形可以由增加元素和注塑形成。相比較注塑模而言，吹塑模需要適中的壓力和夾緊力。所以，他們可以由一種比較輕的材料組成，比如鋁，它有重量輕和高熱傳導(dǎo)性等優(yōu)點(diǎn)。</p><p>　　吹塑容器一般被用來(lái)包裝飲料和其它液體食物。窄瓶頸塑料瓶子則被用來(lái)裝礦物質(zhì)水、牛奶、酒精飲料、碳酸飲料。其它

45、的非食用產(chǎn)品被包裝在吹鑄容器中包括化妝品、醫(yī)藥品、油漆和粉末產(chǎn)品。吹鑄品也被用在生產(chǎn)一些大型的產(chǎn)品上，如船倉(cāng)和固定的儲(chǔ)油罐，它們的容積也許會(huì)達(dá)到10000毫升之高。這些容器被用來(lái)作為地下燃料儲(chǔ)藏庫(kù)和化糞池。</p><p>　　時(shí)期一 預(yù)先成型擠壓 時(shí)期二 吹鑄</p><p>　　圖片2.擠壓吹鑄模具</p><p><b>　　3 旋轉(zhuǎn)鑄模

46、</b></p><p>　　如吹鑄模具，旋轉(zhuǎn)鑄模也被用來(lái)生產(chǎn)空洞的塑料商品，盡管每種方法的原理有很大的不同。在這個(gè)過(guò)程中，一個(gè)經(jīng)過(guò)仔細(xì)稱重得到的塑料粉末置于一半的金屬模中。然后這一半模具被夾在一起并在一個(gè)爐里面進(jìn)行加熱。當(dāng)加熱好以后，模具關(guān)于兩個(gè)軸進(jìn)行每次90°的旋轉(zhuǎn)。在一段時(shí)期之后，塑料將均勻地軟化在模具表面上形成一個(gè)相似層。這個(gè)過(guò)程是很有魅力的，這里有很多原因存在。首先，它是一個(gè)低壓力

47、過(guò)程，模具相應(yīng)就比較簡(jiǎn)單和便宜。第二，產(chǎn)品事實(shí)上是免費(fèi)的。第三，均勻厚度可以很簡(jiǎn)單地被實(shí)現(xiàn)。最后，就可以進(jìn)行產(chǎn)品加固，他們的表面可以按照要求達(dá)到。盡管如此，周期相比于吹鑄或者注塑要長(zhǎng)。模具操作裝置，可以安裝雙旋轉(zhuǎn)，是旋轉(zhuǎn)模具設(shè)備的中心元件。有兩個(gè)主要的設(shè)備類型：穿梭車(chē)系統(tǒng)，如圖像3所示，和搖擺臂系統(tǒng)。旋轉(zhuǎn)模具非常適于生產(chǎn)那些非常大的有厚墻的用其它過(guò)程難于很經(jīng)濟(jì)地生產(chǎn)的產(chǎn)品。最大的旋轉(zhuǎn)模容積被記載大約有75000升左右。</p>

48、;<p>　　圖片3.穿梭車(chē)轉(zhuǎn)動(dòng)模</p><p>　　新西蘭職業(yè)工程師協(xié)會(huì)</p><p><b>　　4 壓縮模制 </b></p><p>　　壓縮模型通常被用來(lái)生產(chǎn)熱固性材料商品，盡管它也可以被用于生產(chǎn)熱塑性塑料。用作熱固塑料的鑄模操作插圖于圖4。一個(gè)很大的數(shù)目的模制熱固塑料產(chǎn)品能夠在電力和電子應(yīng)用中得到發(fā)現(xiàn)。玻璃纖維增

49、加層能夠輕松地增加材料的熱抵抗要求。盡管如此，這個(gè)過(guò)程的局限性是產(chǎn)品必須形狀簡(jiǎn)單而且沒(méi)有薄壁或者易碎內(nèi)嵌物。很多的橡膠產(chǎn)品都是壓縮模制的。它的有用的外表是它有可以形成強(qiáng)大的產(chǎn)品鐐銬的金屬內(nèi)嵌物經(jīng)常被用來(lái)聯(lián)系產(chǎn)品與框架。輪胎是壓力鑄模的最普通的產(chǎn)品。</p><p><b>　　圖片4. 壓縮模制</b></p><p><b>　　5 移動(dòng)模制</b

50、></p><p>　　移動(dòng)模制與壓縮模制很像，除了那個(gè)，取代將材料壓縮在容器里，它被壓縮在一個(gè)分模鏜里然后壓縮在一個(gè)開(kāi)闊空間中然后被壓縮在一個(gè)封閉的模具容器中。移動(dòng)模具的好處是材料的預(yù)熱通過(guò)一個(gè)窄的空洞注入增加了溫度在材料中的分配所以促進(jìn)了熱固塑料的橫向連接反作用力。結(jié)果是周期減少了并且產(chǎn)品的扭曲也減少了。物資流程的改進(jìn)也意味著更多的復(fù)雜情況能夠被生產(chǎn)。有易碎內(nèi)嵌的零件如電力內(nèi)嵌零件、電子元件和放入封套的

51、連接器、集成電路和插栓也能夠輕松地被生產(chǎn)出來(lái)。</p><p><b>　　6 熱力塑形</b></p><p>　　薄片熱力塑形是在1950年被發(fā)展起來(lái)的。限制諸如弱薄墻分部和大的外圍浪費(fèi)把它的用途限制在簡(jiǎn)單的包裝應(yīng)用上面了。盡管如此，在近年來(lái)，在機(jī)器設(shè)計(jì)和材料方面已經(jīng)有了很大的進(jìn)步，已經(jīng)有了一個(gè)很廣的熱力塑形的產(chǎn)品系列。有三種熱力塑形過(guò)程的形式(圖5)：真空成型

52、、空氣壓力成型、和機(jī)械成型。</p><p>　　這些不受高壓的模具，通常來(lái)自鑄造的或者車(chē)出來(lái)的小型或者中型的鋁材，它們不需要一個(gè)好的表面成型。零件表面質(zhì)量很大程度上取決于薄材。</p><p>　　熱力塑形產(chǎn)品可小可大。小的產(chǎn)品在高輸出機(jī)械里運(yùn)用多槽模具制造。這些產(chǎn)品通常能在食品和醫(yī)藥行業(yè)中看到，舉個(gè)例子，剩果子凍或者奶油的容器、杯子、彎管和碟子。這些小的項(xiàng)目能夠相應(yīng)地有一些帶有適度厚度

53、的復(fù)雜的形狀。大型的產(chǎn)品通常由切片在很低的輸入速率下制成，而且它們通常都是簡(jiǎn)單的形狀。費(fèi)舍爾和佩凱爾的真空鑄模機(jī)器聲場(chǎng)著最大的預(yù)成型用作冷藏庫(kù)和冷凍之用。許多其它的內(nèi)部零件也是由相同或相似的過(guò)程制成的。</p><p>　　圖片5. 三種基本的熱力塑形方法</p><p><b>　　7 注塑模具</b></p><p>　　注塑模具一直是一

54、種最普通的塑形成型方法。現(xiàn)今數(shù)不清的電力應(yīng)用、手機(jī)和辦公儀器里的零件都是注塑模制的。最普遍的注塑模具機(jī)器是過(guò)程如圖片6所示可以被分為幾個(gè)時(shí)期的往復(fù)擺螺桿機(jī)器。在增塑階段，伺服單元操作如一個(gè)電爐，融化在絲桿和桶內(nèi)的材料。絲桿，盡管如此，是允許回縮在圓柱頭空間上來(lái)為融化材料提供空間，被稱為蓄水池通常在絲桿梢和封閉閥之間或者來(lái)自先前槽的固化材料。在注塑階段，絲桿是用作一個(gè)活塞來(lái)提供融化材料在兩個(gè)封閉模閥之間從蓄水池到容器的快速移動(dòng)的。因?yàn)槟＞?/p>

55、的溫度控制在固化溫度以下，足夠快地注射模具來(lái)確保容器的完全充滿是很重要的。一個(gè)高的支持或者包裝壓力通常是很有用的，能夠部分地補(bǔ)償材料在冷卻下的熱形式收縮。模具中材料的冷卻通常限制了生產(chǎn)時(shí)間因?yàn)榫酆象w的低熱傳導(dǎo)性。模具，在被冷卻之后，便可以開(kāi)模并且固體的產(chǎn)品被噴出。</p><p>　　盡管絲桿機(jī)器到目前為止是最流行的，活塞注塑機(jī)器也被用來(lái)給予產(chǎn)品一些獨(dú)特的外觀特征。沒(méi)有剪切或者混合的動(dòng)作，因?yàn)榛钊晦D(zhuǎn)動(dòng)。最后的模

56、制零件可以運(yùn)用兩種或多種旋轉(zhuǎn)顏色來(lái)作一種大理石的修飾。這也許是一定產(chǎn)品渴求的完成品。無(wú)論機(jī)器怎么的不同，注塑模具生產(chǎn)一種高生產(chǎn)率產(chǎn)品并確保產(chǎn)品有許多很號(hào)的細(xì)節(jié)如滾花、定位栓、固定孔、軸襯、肋骨、凸緣等等。所有的這些特征都能夠消除許多低平衡裝配和最后工序。</p><p>　　很大一部分產(chǎn)品都能注塑模制的。其中包括 (a) 微小產(chǎn)品、在小精密度上的，多腔模具，如表元件和微電子元件；(b) 中等尺寸產(chǎn)品，在精確機(jī)器或

57、者相對(duì)旋轉(zhuǎn)以非常大的數(shù)目連續(xù)安裝，和 (c) 大型產(chǎn)品，由大型機(jī)器模制，如汽車(chē)的儀表板結(jié)構(gòu)、電視機(jī)箱、花園家具、和小型船體。許多大型的塑料零件都有穩(wěn)固的表面和蜂窩狀的內(nèi)部結(jié)構(gòu)，所以這個(gè)過(guò)程也是一個(gè)結(jié)構(gòu)的泡沫模制。</p><p><b>　　8 反作用注塑模</b></p><p>　　反作用注塑模具是一個(gè)相應(yīng)地新的過(guò)程，包括快速混合、精確比例、兩個(gè)或更高反應(yīng)液體部

58、分和快速注塑混合物到一個(gè)封閉模腔在模具中用很短的時(shí)間發(fā)生反應(yīng)產(chǎn)生固體產(chǎn)品。這個(gè)過(guò)程特別適于生產(chǎn)相比于熱塑性注塑模的大型和相應(yīng)基金總額少花費(fèi)少的薄壁零件。這個(gè)過(guò)程也是能耗的，但是需要對(duì)復(fù)雜反應(yīng)的良好控制。</p><p><b>　　9 總結(jié)</b></p><p>　　大體上，每個(gè)模制過(guò)程要考慮的主要是材料、產(chǎn)品、花費(fèi)中的正反兩方面。塑料工業(yè)在當(dāng)今的制造工業(yè)中起著重

59、要的作用。塑料模制是最流行的過(guò)程。與此相反注塑模具繼續(xù)統(tǒng)治</p><p>　　圖片6. 注塑模操作順序</p><p>　　著這個(gè)部門(mén)，其它的模制過(guò)程對(duì)生產(chǎn)特殊產(chǎn)品起著作用。面對(duì)著種種挑戰(zhàn)，新的工序使得他們走向市場(chǎng)。意識(shí)到能量的消耗，模制機(jī)器生產(chǎn)商們開(kāi)始注重革新性設(shè)計(jì)來(lái)節(jié)約這個(gè)過(guò)程中的能量損耗。對(duì)這些生產(chǎn)商們也有一個(gè)需求就是發(fā)展更小或者更大的模制機(jī)器來(lái)滿足消費(fèi)者的需求。事實(shí)上是越來(lái)越多新