机械工程模具方向毕业设计外文翻译.doc

华南理工大学广州学院本科生毕业设计（论文）翻译英文原文名 English for Die Mould Design and Manufacturing 中文译名 模具设计与制造专业英语 英文原文版出处： 北京大学出版社3月 第1版 译文成绩： 良好 指导教师（导师组长）签名： 译文：2.4.4注塑模具热固性成型化合物可以通过连续自动送进成型加工过程 。加热注入型腔,然而,不应该包含部分材料储备材料,只在熔融状态。热固性材料才能注塑模制材料卷对应的体积产生部分注入浇道中。这将有利于模具与在高频烤炉中预先干燥，取出之前测量进入传递料筒的材料。最有利的和最准确的计量在这种情况下,与常规上的压模法也实现了预压制。因为他们已经一定的密度,更大的风压差可以注射油缸的尺寸,具有决定性的影响所需的注射压力。因为材料注入是通过一个小喷嘴孔非常均匀注入的热渗透过程。而在压塑模具注射过程中,材料不很容易流动,彻底增塑的材料进入腔铸塑成型，另外材料在被加热的模具加热墙。因此热渗透比与压缩成型，需要一个大大缩短固化时间。传递模塑法是压缩模塑成型工艺方法。特定优势的注塑成型工艺也当长芯必须使用部分的性质。在这种情况下,他们的指导和支持反对单边施压比压缩成型的设计变得容易得多。这也是为什么周围注射敏感的金属部分是可行的原因。型芯和嵌件必须通过相应的设计进入到有利于定位材料的流动路线。 通过传递模具必须满足的要求是基本相同的那些压制模具。由于所需的注射压力,这将在1000到1800bar之间注入注射缸，但是模具型腔内的低一点,但仍高于普通压缩成型,模具必须更加坚定。必须采取特殊设计的排气和成型的模具中使材料已经完全注入如果不遵守，当注射热塑材料模具，空隙和不完整的部分将会导致同样的后果。然而，作为模具的排气不可能以同样的方式，它是在标准的压缩模具，通风口必须定位和尺寸使得他们允许气体逸出材料不让后者堵塞排气通道。一个转移模具结构不同于一个压模，装料室不存在。这已经由注射筒和位于模具中心活塞取代。两者之间的区别两种基本类型的铸塑模具如下:铸塑模具顶部注入汽缸和活塞。.这些模具可以按操作标准,在这种情况下,限制在开模行程中应被考虑。铸塑模具底部注入压注缸和活塞。这种结构形式的模具具有一个强制性的单独注射装置。这通常是一个压力集中与液压缸安装在模具底部操作的注射活塞,与机器上的计时器联锁(传递模塑法)。该成型模具部件和腔以相同的方式与以标准压制模具共同运作。第三章 铸造模具3.1铸造第一个铸件是在公元前4000 3000年期间的铸铜,用石头和金属模具。各种铸造过程已经发展了很长一段时间,每个都有自己的特点及应用,以满足特定的工程和服务需求。很多零部件是由铸件,包括相机、汽化器、引擎模块,曲轴,汽车零部件,农业和铁路设备、管道和管道设备、电动工具、枪管,煎锅,非常大的水力涡轮机组件。铸造可以通过几种方式实现。两个主要的是砂型铸件,在每个周期后一次性使用的模具,压铸,或永久成型,使用相同的金属模具冲模数千甚至数百万次。这两种类型的模具有三个共同的特征。他们都有一个“流道”系统将熔融合金模具型腔。这些通道被称为浇道,分流道和浇口(图3 - 1)。模具可以修改核心形成孔和凹槽或插入成为铸造不可或缺的一部分。镶嵌件加强,减少摩擦,他们比周围的可加工的金属方便加工。例如,钢轴时正确地插入到模腔后导致齿轮的装配铝一步。浇注或注射后,得到的铸件需要后续操作修剪等检查,研磨,维修在运输之前或多或少而已。优质铸件的合金铝或钢需要x射线稳健,被客户接受。某些特殊的铸造工艺是熔模精密熔模铸造、低压铸造、离心铸造。3.2砂型铸造铸造金属的传统方法是在砂型模具,已经使用了数千年。简单的说,砂型铸造包括(a)放置一个模式在沙子的形状所需的铸件印记,(b)将浇注系统,(c)填充结果与熔融金属腔, （d）使金属冷却到凝固，（e）脱离砂模，及（f）中取出铸件(图3 - 2)。对于一个典型的砂型铸造生产操作步骤如图3-3所示。尽管砂型铸造的起源可以追溯到古代,它仍然是最普遍的形式的铸造。仅在美国,约1500万吨金属铸造用这种方法。3.2.1 型砂大多数砂型铸造操作使用硅砂(二氧化硅), 硅砂是岩石经过很长一段时间崩解的产物。砂价格低廉，适合作为模具材料由于其高温性能。一般有两种类型的砂: 天然粘土砂（细砂）和合成（湖砂）。因为它的成分可以更精确地控制,合成砂是大多数铸造厂是首选。选择原砂作模具的几个重要因素砂具有良好的，圆形的颗粒可紧密排列，形成一个光滑的表面。虽然细粒砂提高模具强度，细颗粒也较低的铸型透气性。好的模具和芯允许气体和蒸汽渗透性演化在铸造容易脱模。3.2.2砂型铸造的类型砂型模具的特点是砂子组成的类型和方法便于生产和制造。有三种基本类型的砂型模具:湿砂、冷芯盒、硬化砂型模具。最常见的模具材料是环保的湿模砂,这是一个混合的沙子,泥土和水。“湿”一词是指模具中的砂子是潮湿的或者当金属金属溶液被灌进去时是湿的。湿砂造型是最便宜的方法的模具。粘土干砂型方法,模具表面是干燥的,通过将模具存储在空气或干燥炉。这些模具通常用于大型铸件且由于更高的强度。砂模在浇注熔融金属之前也要烘（烤）干；它们比湿砂模更强大且给铸件更好尺寸精度和表面光洁度。然而，这种方法有缺点：模具变形相当大；由于模具的较低退让性铸件更容易形成热裂纹；同时需要一定的干燥时间而减慢生产率。在冷芯盒模具过程中,各种有机和无机粘结剂混合进沙子债券的谷物化学更大的力量。这些模具是在尺寸上比湿砂模具更准确但更昂贵。在化学硬化模具过程中,合成液体树脂混合着沙子,混合物在室温下变硬。因为模具的焊接和冷却箱过程中发生不热,他们被称为冷固化过程。以下是砂型模具的主要组件(图3 - 2): (1)模具本身,它是由一个型（砂）箱、两件套模具组成由一个在顶部型箱和底部。它们之间的接缝是分型线。当使用超过两块时,额外的部分被称为耐火侧墙。(2) 浇口杯或倒杯,熔融金属的是倾斜倒入。(3) 浇口，通过熔融金属流下。 (4)流道系统,渠道,将熔融金属从浇口模具型腔。浇口是入口进入模具型腔。(5)冒口,提供额外的金属铸件在凝固收缩。图3 - 2显示了两个不同类型的冒口:暗冒口和一个明冒口。 (6) 模芯，用沙子做成的镶件。被放置在模具中形成空心区域或其他制定的铸件内部表面。模芯也被用于铸件外部形成像铸件表面的文字或者深入铸件的槽等特征。 (7) 排空阀，放置在模具进行了熔融金属接触时产生的气体中的砂模具和型芯。他们还可以从模具型腔排气熔融金属流进模具。3.2.3模型模型是用来模砂混合物倒入铸件的形状。他们可能会由木头、塑料或金属。模式材料的选择取决于铸件的大小和形状,尺寸精度,所需的铸件数量,成型过程。因为模式是重复使用模具,材料的强度和耐用性选择模式必须反映铸件模具会产生的数量。他们可能会使材料的组合来减少磨损的关键地部位。模式通常涂有脱模剂促进其从模具中取出。模型可以被设计成具有各种特点适合应用程序和经济需求。一整块模板也叫做松模或整体模，一般用于简单的形状和小批量生产。整体模一般用木材制成，比廉价。组合模是两块模，分别制成铸件的一部分型腔；用这种方法可以生产形状复杂的铸件。双面模板模式是一个受欢迎的类型的安装模式,对分模是由上下两个模每个一半的一个或多个分割模式一个板的两端(图.3-4)。在这样的结构,可以安装在浇注系统阻力的模式。这种类型的模式是最常用于结合成型机和大型生产运行生产小型铸件。最近一个重要的发新展是快速成型模具和模型制造的实际应用程序。在砂型铸造中,例如一个模式可以伪造一个快速原型机和系垫板的一小部分时间和成本的加工模式。有几种快速成型技术,这些工具可以快速生产。模型设计是一个关键的方面总铸造操作。设计应该去除的金属收缩、案例砂型的锥形或草案(图3 - 5), 和模腔中适当的金属流动方案。3.2.4型芯对铸件内部孔或通孔,比如那些在一个汽车引擎块或阀体,会利用到型芯。型芯被放置在模具型腔铸造形成的内部表面铸造,并从完成的部分在铸造和进一步处理。如同模具、芯必须具备强度、渗透率、抗高温能力,和崩散性;因此,型芯是由砂型机组。型芯是由型芯座固定。这些深处被添加到模式支持的核心,并提供通风口使空气排出(图3 - 6)。型芯的一个常见的问题是对于一些铸造要求,如需要休息的情况下,他们可能缺乏足够的空腔结构支撑。使型心在变化中保持不变，金属支架（项圈）用于锚主型芯在适当的位置（图3-6）。型芯通常在某种程度上制造类似,于制造模具,绝大多数是制造壳、化学硬化或冷芯盒工艺。在芯盒芯形成,用于一样,模式是用来形成砂模具。砂可能被装入带有扫描的砂芯盒里，或被压缩型芯吹砂机吹入砂芯盒里面。后者的优势生产统一的核心和操作在很高的生产速度。3.2.5砂型铸造机最为人熟知的方法是现今仍使用的简易铸造，简易铸造即用手敲击砂子（填充）或冲压在模板中形成的。适用于大多数操作,但是,周围的沙子混合物压缩模式由成型机完成(图.3-7)。这些机器消除艰苦劳动,提供高质量的铸件,提高部队的应用和分布,安全控制的方式操纵模具,和增加产量。成型工艺的机械化可以通过颠簸组件进一步辅助。型（砂）箱、型砂和模式首先被放在铁砧上安装了一个基准面,然后向上震由空气压力在快速的时间间隔。惯力使附近的砂子紧凑方法。周围的沙子震动产生最高的压实水平分型线,而在挤压,压实是最高的挤压头(图3 - 7)。 因此,更加均衡的密度可以通过结合挤压和震动实现。在上型箱造型和下型箱部分形成一个垂直的室壁砂吹和压实(图3 - 8)。在垂直无箱造型,模式的部分形成一个垂直的室壁砂吹和压实(图3 - 8)。模具具有密封的水平面个导线向分型线的垂直地往大输送机浇注。这个操作很简单,消除了需要处理的型（砂）箱,允许生产速度非常高,特别是当操作的其他方面(如取心和浇注)自动化。 抛砂机高压下沙子填满型（砂）箱均匀流。他们是用来填补大玻璃瓶和通常由机器。从其叶片的叶轮机扔沙子或杯以如此高的速度,这台机器不仅放置沙子而且放到适当的地方。在冲压模中，砂子通过控制爆炸或瞬间释放出压缩气体结合。这种方法生产的模具有同一的强度和渗透性。在真空成型,也被称为“V”过程中,模式是紧密的塑料薄片覆盖。型（砂）箱放置在覆盖模式和充满了干燥的无粘结的型砂。然后放在第二个的塑料板材的沙子,和真空行动变硬砂,模式可以撤回。该模具的两半就是用这种方式制造和组装。在浇注过程中,模具仍在真空状态下铸造作业。金属凝固时,真空是关闭和沙子,释放铸造。真空成型生产铸件与高质量的细节和尺寸精度。它尤其适合大、相对平坦的铸件。3.2.6沙型铸造操作砂模的操作方法。当模具成型且型心放置在内部合适的位置，堵塞两个孔（延长处理），夹紧有利于防止当金属熔液灌入模具内时，模具的各部分由于压力而分离。浇注系统的设计合理的熔融金属输送到模具型腔是很重要的。如前所述,湍流必须最小化、空气和气体必须允许通风口等方法逃避,和适当的温度梯度必须建立和维护以减少收缩和孔隙度。 T 冒口的设计也很重要,以提供必要的熔融金属在凝固的铸造。浇口杯也可能作为冒口。完整的操作砂型型铸造图3 - 9所示。在图3 9(a),机械制图的部分是用于生成的设计模式。考虑部分收缩和制定必须的图纸。(b)(c),模式已经安装在板配有针对齐。注意的核心输出设计的核心。在(d)(e),芯盒作为的核心部分,粘贴在一起。核心将用于生产的中空区域部分(a)所示。(f),应付一半的模具被保护应对模板组装调整定位销的型（砂）箱,并附加插入形成浇口和冒口。在(g),瓶与沙子和撞击板和插入删除。在(h), 一半阻力生产以类似的方式嵌入模式。下面放置一个底板与拖针。(i)的模式,瓶,和型（砂）箱板倒,和模式是撤回,留下适当的印记。在(j),核心是拖内腔设置在的地方。在(k)中,模具将接近于的阻力和固定的装配压力。型（砂）箱内然后受到压力抵消活跃部队在液体中,这可能会提振(左),金属凝固后,铸件从模具中移除。在(m),浇口和冒口切断和回收,以及铸件清理,检查、热处理(必要时)。金属冷凝后，铸件从模具中取出，砂粒和粘附的氧化层用振动（分离机）或爆破砂子的方法处理掉。铸件通常使用喷钢砂或粗砂处理（喷丸处理）。浇口和浇道用可燃氧气、锯、剪子、砂轮切割；或将其整个镶入模具当中。钢铸件的浇口和浇道也用炭精电弧气或燃烧去除。铸件可通过电化学手段清洗或用化学酸洗去除表面氧化物。几乎所有常规金属都可以使用砂型铸造。获得的表面光洁度在很大程度上是取决于用于制造模具的材料。虽然尺寸精度不如其他铸造过程，然而复杂的形状可以通过这步骤,例如铸造铸铁发动机块和非常大的螺旋桨的远洋定期客轮。沙型铸造可以为相对较小的生产运行、经济和设备成本通常是低。铸件的表面在后续加工操作是非常重要的,因为如果铸件清理不当和沙子颗粒停留在表面会影响制件的质量。如果地区位置铸造没有完成铸造成型，其缺陷需要被填满焊缝金属修复。砂型铸件通常有粗糙,颗粒状表面,根据模具的质量和使用的材料。铸件可以通过热处理后提高其所需某些属性达到预期的使用功能;这些过程对钢铸件尤为重要。完成精加工可能涉及加工校直,或锻造模具获得最终的尺寸。金属表面轻微的缺陷，可采用环氧树脂填充补满充,特别是对铸铁铸件,因为他们很难焊接。检测是一个重要的最后一步，是开展了以确保铸件满足所有的设计和质量控制要求。 原文Chapter 1 Stamping Forming and Die Design 2.4.4 Transfer Molds Thermosetting molding compounds can be processed by the transfer molding process. The hot injection cylinder, however, should not contain material reserves for several parts since the material would, only cure in the heat. Thermosets can only be transfer molded if the material volume corresponds to the volume of the part to be produced plus the sprue. It would be expedient to mold with material that has been predried in a high-frequency oven, to be taken out of the oven only just before it is metered into the transfer cylinder. The most favorable and most accurate type of metering in this caseas with conventional compression moldingisalso achieved with precompressed pellets. As they are already of a certain density, greater leeway can be given to the dimensions of the injection cylinder, which has a decisive influence on the injection pressure required. Because the material is injected through a small nozzle bore very uniform heat permeation is achieved. Whereas in compression molding-even with well prewarmed pelletsthe material does not flow very easily, thoroughly plasticized material enters the cavities in transfer molding. The material is additionally warmed by the heated mold walls. Heat permeation is therefore better than with compression molding. A considerably shorter cure time is needed for the transfer molding process than for the compression molding method. The transfer molding process also is of particular advantage when long cores have to be employed due to the nature of the parts. In this instance, their guidance and support against unilateral pressure is considerably easier to design than for compression molding. This is also the reason why injection around sensitive metal parts is possible. The cores and the inserts must be advantageously positioned in the flow path of the material by arranging the runners accordingly. The requirements to be met by a transfer mold are basically the same as those for a compression mold. Due to the injection pressure required, which lays around 1,000 to 1,800 bar in the injection cylinder but is somewhat lower inside the mold cavity, although still higher than hwith ordinary compression molding, the mold must be more solidly constructed. Particular care must be taken with the venting of the shape-giving cavities as the mold is already fully clamped during injection. If this is not observed, voids and incomplete parts will result in the same manner as can be experienced when injection molding thermoplastics material. However, as venting of the mold is not possible in the same way as it is done on standard compression molds, air vents have to be positioned and dimensioned so that they permit the gases to escape from the material without allowing the latter to clog up the venting channels. The construction of a transfer mold differs from that of a compression mold in that the charging chamber does not exist. This has been replaced by an injection cylinder and piston positioned in the center of the mold. One differentiates between the two basic types of transfer mold as follows: transfer mold with top injection cylinder and piston. These molds can be operated on standard presses, in which case the restriction in the opening stroke has of course to be taken into consideration. Transfer mold with bottom injection cylinder and piston. For molds of this type of construction a press with a separate injection unit is compulsory. This is usually a press with a hydraulic cylinder mounted centrally underneath the mold table to operate the injection piston, which is interlocked with the timers on the machine (transfer molding). The shape-forming mold parts and cavities are executed in the same manner as those on standard compression molds.Chapter 3 Casting Dies 3.1 Casting The first castings were made during the period 40003000 B.C., using stone and metal molds for casting copper. Various casting processes have been developed over a long period of time, each with its own characteristics and applications, to meet specific engineering and service requirements. Many parts and components are made by casting, including cameras, carburetors, engine blocks, crankshafts, automotive components, agricultural and railroad equipment, pipes and plumbing fixtures, power tools, gun barrels, frying pans, and very large components for hydraulic turbines. Casting can be done in several ways. The two major ones are sand casting, in which the molds used are disposable after each cycle, and die casting, or permanent molding, in which the same metallic die is used thousands or even millions of times. Both types of molds have three common features. They both have a “plumbing” system to channel molten alloy into the mold cavity. These channels are called sprues, runners, and gates (Fig. 3-1). Molds may be modified by cores which form holes and undercuts or inserts that become an integral part of the casting. Inserts strengthen and reduce friction, and they may be more machinable than the surrounding metal. For example, a steel shaft when properly inserted into a die cavity results in an assembled aluminum step gear after the shot. After pouring or injection, the resulting castings require subsequent operations such trim-ming, inspection, grinding, and repairs to a greater or lesser extent prior to shipping. Premium-quality castings from alloys of aluminum or steel require x-ray soundness that will be acceptable by the customer. Certain special casting processes are precision-investment casting, low-pressure casting, and centrifugal casting.3.2 Sand CastingThe traditional method of casting metals is in sand molds and has been used for millennia. Simply stated, sand casting consists of (a) placing a pattern having the shape of the desired casting in sand to make an imprint, (b) incorporating a gating system, (c) filling the resulting cavity with molten metal, (d) allowing the metal to cool until it solidifies, (e) breaking away the sand mold, and (f) removing the casting (Fig. 3-2). The production steps for a typical sand-casting operation are shown in Fig. 3-3. Although the origins of sand casting date to ancient times, it is still the most prevalent form of casting. In the United States alone, about 15 million tons of metal are cast by this method each year.3.2.1 Sands Most sand casting operations use silica sand (SiO2), which is the product of the dis- integration of rocks over extremely long periods of time. Sand is inexpensive and is suitable as mold material because of its resistance to high temperatures. There are two general types of sand: naturally bonded (bank sand) and synthetic (lake sand). Because its composition can be controlled more accurately, synthetic sand is preferred by most foundries. Several factors are important in the selection of sand for molds. Sand having fine, round grains can be closely packed and forms a smooth mold surface. Although fine-grained sand enhances mold strength, the fine grains also lower mold permeability. Good permeability of molds and cores allows gases and steam evolved during casting to escape easily. 3.2.2 Types of Sand Molds Sand molds are characterized by the types of sand that comprise them and by the methods used to produce them. There are three basic types of sand molds: greensand, cold-box, and no-bake molds. The most common mold material is green molding sand, which is a mixture of sand, clay, and water. The term “green” refers to the fact that the sand in the mold is moist or damp while the metal is being poured into it. Greensand molding is the least expensive method of makingmolds. In the skin-dried method, the mold surfaces are dried, either by storing the mold in air or by drying it with torches. These molds are generally used for large castings because of their higher strength. Sand molds are also oven dried (baked) prior to pouring the molten metal; they are stronger than greensand molds and impart better dimensional accuracy and surface finish to the casting. However, this method has drawbacks: distortion of the mold is greater; the castings are more susceptible to hot tearing because of the lower collapsibility of the mold; and the production rate is slower because of the drying time required. In the cold-box mold process, various organic and inorganic binders are blended into the sand to bond the grains chemically for greater strength. These molds are dimensionally more accurate than greensand molds but are more expensive. In the no-bake mold process, a synthetic liquid resin is mixed with the sand; the mixture hardens at room temperature. Because bonding of the mold in this and in the cold-box process takes place without heat, they are called cold-setting processes. The following are the major components of sand molds (Fig. 3-2): (1) The mold itself, which is supported by a flask. Two-piece molds consist of a cope on top and a drag on the bottom. The seam between them is the parting line. When more than two