CA6140车床主轴箱体工艺分析及镗夹具设计【4张CAD图纸+毕业答辩论文】
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ca6140
车床
主轴
箱体
工艺
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夹具
设计
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cad
图纸
毕业
答辩
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目 录
内容摘要1
关 键 词1
Abstract1
Key words1
1 前言2
2 主轴箱体加工工艺规程设计4
2.1零件的作用4
2.2零件的工艺分析4
2.3主轴箱体加工的主要问题和工艺过程设计所应采取的相应措施7
3 专用夹具设计22
3.1加工左端平面镗孔夹具设计24
3.2定位基准的选择25
3.3切削力的计算与夹紧力分析25
3.4夹紧元件及动力装置确定26
3.5镗套、镗套、镗模板及夹具体设计26
3.6夹具精度分析26
3.7夹具设计及操作的简要说明27
4 致谢28
参考文献29
内容摘要: 本设计要求“以质量求发展，以效益求生存”，在保证零件加工质量的前提下，提高了生产率，降低了生产成本，是国内外现代机械加工工艺的主要发展方面方向之一。通过对60140 主轴箱体零件图的分析及结构形式的了解，从而对主轴箱体进行工艺分析、工艺说明及加工过程的技术要求和精度分析。然后再对主轴箱体的底孔、轴承孔的加工进行夹具设计与精度和误差分析，该工艺与夹具设计结果能应用于生产要求。
关 键 词：主轴箱 加工工艺 定位 夹具设计
Abstract:This Paper requires that with quality beg development, with benefits seek to live on to store . Under the prerequisite of guaranteeing the quality of element processing , raising productivity and reducing production cost is one of mainly direction of domestic and international modern machining technology developing. Through knowing and analysis the configuration of the casing part drawing for WH212 gear reducer, we master how to analysis the process , make process explanation , analysis the technical requirement and the precision of gear reducer. Then , we should carry out the design of clamping apparatus and analysis the precision and error for the processing of bearing hole and the base hole of the casing of gear reducer.In the last,this technology and the design result of clamping apparatus can be applied` in production requirement.
Key words:principal axis processing technology Fixed position Tongs design
1 前 言
加工工艺及夹具毕业设计是对所学专业知识的一次巩固，是在进行社会实践之前对所学各课程的一次深入的综合性的总复习，也是理论联系实际的训练。
机床夹具已成为机械加工中的重要装备。机床夹具的设计和使用是促进生产发展的重要工艺措施之一。随着我国机械工业生产的不断发展,机床夹具的改进和创造已成为广大机械工人和技术人员在技术革新中的一项重要任务。
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外文资料翻译 Mold Cooling One fundamental principle of injection molding is that hot material enters the mold, where is cools rapidly to a temperature at which it solidifies sufficiently to retain the shape of the impression. The temperature of the mold is therefore important as it governs a portion of the overall molding cycle. While the meld flows more freely in a hot mold, a greater cooling period is required before the solidified molding can be ejected. Alternatively, while the meld solidifies quickly in a cold mold it may not reach the extremities of impression. A compromise between the two extremes must therefore be accepted to obtain the optimum molding cycle. The operating temperature for a particular mold will depend on a number of factors which include the following: type and grade of material to be molded; length of flow within the impression; wall section of the molding; length of the feed system, etc. It is often found advantageous to use a slightly higher temperature than is required just to fill the impression, as this tends to improve the surface finish of the molding by minimizing weld lines, flow marks and other blemishes. To maintain the required temperature differential between the mold and plastic material, water (or other fluid) is circulated through holes or channels within the mold. These holes or channels are termed flow-ways and the complete system of flow ways is termed the circuit. During the impression filling stage the hottest material will be in the vicinity of the entry point, i.e. the gate, the coolest material will be at the point farthest from the entry. The temperature of the coolant fluid, however, increases as it passes through the mold. Therefore to achieve an even cooling rate over the molding surface it is necessary to locate the incoming coolant fluid adjacent to hot molding surface and to locate the channels containing heated coolant fluid adjacent to cool molding surface. However as will be seen from the following discussion, it is not always practicable to adopt the idealized approach and the designer must use a fair amount of common sense when nts laying out coolant circuits if unnecessarily expensive molds are to be avoided. Units for the circulation of water (or other fluid) are commercially available. These units are simply connected to the mold via flexible hoses, with these units the molds temperature can be maintained within close limits. Close temperature control is not possible for using the alternative system in which the mold is connect to a cold water supply. It is the mold designers responsibility to provide an adequate circulating system within the mold. In general, the simplest systems are those in which holes are bored longitudinally through the mold plates. However, this is not necessarily the most efficient method for a particular mold. When using drillings for the circulation of the coolant, however, these must not be positioned too close to the impression (say closer than 16mm) as this is likely to cause a marked temperature variation across the impression, with resultant molding problems. The layout of a circuit is often complicated by the fact that flow ways must not be drilled too close to any other holes in the same mold plate. It will be recalled that the mold plate has a large number of holes or recesses, to accommodate ejector pins, guide pillars, guide bushes, sprue bush, inserts, etc. How close it is safe to position in a flow way adjacent to another hole depends to a large extent on the depth of the flow way drilling required. When drilling deep flow ways there is a tendency for the drill to wander off its prescribed course. A rule which is often applied is that for drillings up to 150mm deep the flow way should not be closer than 3mm to any other hole. For deeper flow ways this allowance is increased to 5mm. To obtain the best possible position for a circuit it is good practice to lay the circuit in at the earliest opportunity in the design. The other mold items such as ejector pins, guide bushes, etc. can then be positioned accordingly. nts Mold Cavities and Cores The cavity and core give the molding its external shapes respectively, the impression imparting the whole of the form to the molding. When then proceeded to indicate alternative ways by which the cavity and core could be incorporated into the mold and we found that these alternatives fell under two main headings, namely the integer method and the insert method. Another method by which the cavity can be incorporated is by means of split inserts or splits. When the cavity or core is machined from a large plate or block of steel, or is cast in one piece, and used without bolstering as one of the mold plates, it is termed an integer cavity plate or integer core plate. This design is preferred for single-impression molds because of characteristics of the strength, smaller size and lower cost. It is not used as much for multi-impression molds as there are other factors such as alignment which must be taken into consideration. Of the many manufacturing processes available for preparing molds only two are normally used in this case. There are a direct machining operation on a rough steel forging or blank using the conventional machine tool, or the precision investment casting technique in which a master pattern is made of the cavity and core. The pattern is then used to prepare a casting of the cavity or core by or special process. A 4.25% nickel-chrome-molybdenum steel (BS 970-835 M30) is normally specified for integer mold plates which are to be made by the direct machining method. The precision investment casting method usually utilizes a high-chrome steel. For molds containing intricate impressions, and for multi-impression molds, it is not satisfactory to attempt to machine the cavity and core plates from single blocks of steel as with integer molds. The machining sequences and operation would be altogether too complicated and costly. The inset-bolster assembly method is therefore used instead. The method consists in machining the impression out of small blocks of steel. These small blocks of steel are known, after machining, as inserts, and the one which forms the male part is termed the core insert and, conversely, the one which forms the female part the cavity inserts. These are then inserted and securely fitted into holes in a substantial block or plate of steel called a bolster. These holes are either sunk part way nts or are machined right through the bolster plate. In the latter case there will be a plate fastened behind the bolster and this secures the insert in position. Both the integer and the insert-bolster methods have their advantages depending upon the size, the shape of the molding, the complexity of the mold, whether the single impression or a multi-impression mold is desire, the cost of making the mold, etc. It can therefore be said that in general, once the characteristics of the mold required to do a particular job which have been weighed up, the decision as to which design to adopt can be made. Some of these considerations have already been discussed under various broad headings, such as cost, but to enable the reader to weigh them up more easily, when faced with a particular problem, the comparison of the relative advantages of each system is discussed under a number of headings. Unquestionably, for single impression molds integer design is to be preferred irrespective of whether the component form is a simple or a complex one. The resulting mold will be stronger, smaller, less costly, and generally incorporate a less elaborate cooling system than the insert-bolster design. It should be borne in mind that local inserts can be judiciously used to simplify the general manufacture of the mold impression. For multi-impression molds the choice is not so clear-cut. In the majority of cases the insert-bolster method of construction is used, the ease of manufacture, mold alignment, and resulting lower mold costs being he overriding factors affecting the choice. For components of very simple form it is often advantageous to use one design for one of the mold plate and the alternative design for the other. For example, consider a multi-impression mold for a box-type component. The cavity plate could be of the integer design to gain the advantages of strength, thereby allowing a smaller mold plate, while the core plate could be of insert-bolster design which will simplify machining of the plate and allow for adjustments for mold alignment. Feed System nts It is necessary to provide a flow-way in the injection mold to connect the nozzle (of the injection machine) to each impression. This flow-way is termed the feed system. Normally the feed system comprises a sprue runner and gate. These terms apply equally to the flow-way itself, and to the molded material which is removed from the flow-way itself in the process of extracting the molding. A typical feed system for a four-impression, it is seen that material passes through the sprue, main runner, branch runners and gate before entering the impression. As the temperature of molten plastic is lowered while going through the sprue and runner, the viscosity will rise; therefore, the viscosity is lowered by shear heat generated when going through the gate to fill the cavity. It is desirable to keep the distance that the material has to travel down to a minimum to reduce pressure and heat losses. It is for this reason that careful consideration must be given to the impression layout and gates design. 1. Sprue A spru is a channel through to transfer molten plastic injected from the nozzle of the in injector into the mold. 2. Runner A runner is a channel that guides molten plastic into the cavity of a mold. 3. Gate A gate is an entrance through which molten plastic enters the cavity. The gate has the following functions: restricts the flow and the direction of molten plastic; simplifies cutting of a runner and molding to simplify finishing of parts; quickly cools and solidifies to avoid backflow after molten plastic has filled up in the cavity. 4. Cold Slug Well The purpose of the cold slug well, shown opposite the sprue, is theoretically to receive the material that has chilled at the front of the nozzle during the cooling and ejection phase. Perhaps of greater importance is the fact that it provides positive means whereby the sprue can be pulled from the sprue bush for ejection purposes. The sprue, the runner, and the gate will be discarded after a part is complete. However, the runner and the gate are important items that affect the quality or the cost of pats. nts nts 模具冷却系统 注塑生产的基本原理是把高温熔体注入模具型腔，熔体在型腔内迅速冷却到固化温度，并保持一定形状。由于模具温度在一定程度上控制塑件的整个成型周期，因此在生产中非常重要。熔体在高温模具内流动顺畅，但固化塑件推出前，一定的冷却阶段是比不可少的，另一方面，熔体在温度较低额模具中固化较快，又可能造成塑件末端填充不满。因此必须在这两种对立的条件中选择一个平衡点，以获得最佳的生产循环。 模具的工作温度与几种因素有关，包括成型材料的等级与分类、熔体在型腔内的流动路线、塑件壁厚以及浇注系统长度等。使用比充模要求稍 高的温度注塑比较有利，这样生产的塑件熔接痕少、流痕不明显，其他缺陷也较少，因此可提高塑件表面质量。 为保持模具和塑料熔体之间所需的温差，水（或其他液体）在模具上的通道或通孔中循环。这些通道或通孔称为流道或水道，整个水道系统称为冷却循环系统。 在充模阶段，温度最高的熔体位于进入口，即浇口附近；温度最低的熔体位于距进入口最远的地方。冷却介质在模具内循环时，介质温度将升高。因此，为使塑料表面获得均匀的冷却速率，冷却通道的入口应开设在高温塑件附近，受热后冷却介质温度升高，出口开设在低温塑件附近，设计者往往凭借经验设 计冷却水道。 冷却水（或其他冷却介质）回路所需的部件在市场上就可以买到。这些部件通过软管与模具直接连在一起，通过这些部件形成的冷却回路，模具温度便控制在要求的范围内。但是，使用这种直接与冷水相连的冷却回路是不可能精确的控制模具的温度的。 为模具提供合适的冷却系统是设计者的责任。通常，最简单的冷却系统是在模板上纵向钻出通孔。然而对于精密模具，这不是最有效的冷却方法。 使用钻孔的方法加工冷却水道时，冷却通道与塑件距离一定不能太近（即距离小于 16mm），如果距离太近，有可能引起整个型腔的温度发生显著的变化， 使塑件出现问题。 冷却水道不能距离同一模板上任何其他的孔道太近，这使得冷却回路的布局通常比较复杂。，模板上存在大量的孔道或凹陷，用来安装推杆、导柱、导套、浇nts 口套以及镶件等。冷却水道与其他孔道之间的安全距离在很大程度上取决于所需冷却水道的钻入深度。流道深度较深时， 钻头有偏离预定加工路线的趋势。常用的规则是钻入深度达到 150mm 的冷却水道与其他孔道距离不小于 3mm，比这更深的流道所需的距离增加到 5mm。 为获得最佳的冷却回路，设计初期就考虑冷却回路的位置不失为一种好方法。其他模具零件，如推杆、导套等，可相应 的确定安装位置。 型腔和型芯 模具的型腔和型芯分别形成塑件内部和外部形状，型腔形状决定了塑件外部形状，接下来我们简要说明选择哪种方式把型腔和型芯安装在模具中，这些方式可归纳为两大类，即整体式和镶拼式。另一种组成型腔的方式是加入拼块或滑块。 当型腔或型芯由一块大的钢板或刚块加工而成，或者铸成一体，不需使用支承板件而形成一块模板时，就构成整体式型腔板或型芯板。这种设计因具有强度高、尺寸小和成本低的特性，而主要应用在单型腔模具中。整体式型腔和型芯一般不用在多用于 多型腔模具中，因为多型腔模具设计时必须考虑一些其他因素，例如安装组合镶件等。 在模具制造的众多方法中，用于加工整体式型腔板或型芯板的方法主要有两种：使用传统机床对粗锻钢胚料直接加工，或利用精确的熔模铸造技术将胚料加工成型腔和型芯。用于制造型腔和型芯的胚料经常需要特殊工艺的处理。 通常， 4.25%的镍铬钼合金钢（ BS970-835M30）是生产整体模板的制定材料，选用这种材料时采用直接的机加工方式。 精确的熔模铸造常常用来加工高铬钢。 对于成型部模具和位复杂的多腔模，也像整体式模具那样用一块钢材加工型腔和 型芯并不容易。如果采用整体式结构，则加工顺序和操作过程将变得非常复杂，成本也高，因此镶拼式装配方式替代了整体式。 镶拼式型腔由小钢块加工而成。加工后的小钢块作为镶件，形成型芯部分的称为型芯嵌块，相反的，形成型腔部分的称为型腔嵌件。然后，把这些嵌件牢固的安装在被称为垫板的孔中，垫板有实心钢板或钢块加工而成。这些安装孔有的是由垫块的局部凹陷形成，有的是在垫板上直接加工而成的。在后一种方式中，nts 垫板后部还要加一块模板，起加固作用，确保镶件安装到位。 整体式和镶拼式结构均有优点，这取决于塑件尺寸和形状、模具的复杂程 度、所需的是单型腔模具还是多型腔模具以及模具的制造成本等。通常，塑件的形状、尺寸等特性确定后，采用哪种形式的型腔和型芯就已经确定了。 在不同的章节中，我已经讨论过型腔和型芯的安装方式所涉及的问题，例如成本等。但为使读者在处理特殊问题时更容易知道重点所在，我们将用一定的章节再次讨论每种结构优缺点的对比。 毫无疑问，对于单型腔模具，无论是简单还是复杂，整体式型腔是首选方式。若选择整体式，则模具的强度高、体积小、成本低，而冷却系统的设计却比镶拼式简单、方便。设计时需要常记于心的是，适当的使用镶件可以简单化模具型腔的加工制造难度。 对于多型腔模具选择哪种方式不是很明显。大多数多型腔模具采用镶拼式结构，这种结构加工简单、装配容易、模具成本低，这些是影响选择哪种结构形式的最重要因素。一种非常简单且具有很多优点的设计形式是采用一种形式设计模板，而采用另一种形式设计模具的其他部分。例如，采用箱型组件设计多型腔模具。型腔板设计成小型整体式模板，以满足模具高强度的要求；型芯板则设计成镶拼式，可以简化模板加工过程，并且能根据模具需要进行调整。 浇注系统 在注塑 模具中，连接注塑机喷嘴和各个分流道型腔的流动通常是非常必要的，这种进料通道称为浇注系统。 通常，浇注系统由主流道、分流道和浇口组成。这些术语应用在相应的进料通道本身，以及取出塑件时从进一同取出的料通道中浇注系统凝料。 可以看出，原料通过主流道、第一分流道、第二分流道和浇口注入型腔中。熔融塑料通过主流道和分流道时温度降低而使熔体粘度升高，然而当熔体通过浇口填入型腔时，由于剪切作用产生的热量又使粘度降低。浇注系统要保持适当长度，使熔体的压力减少且热量损失降到最低。因此，设计时必须充分考虑型腔分布和浇口形式。 1、 主 流道 主流道是将熔融塑料从注塑机喷嘴传递到模具型腔的通道。主流道是浇口套nts 的一部分，浇口套是独立于模具的单独零件。 2、 分流道 分流道是引导熔融塑料进入模具型腔的通道。 3、 浇口 浇口是熔融塑料进入型腔的入口。浇口有以下作用：约束熔体流动；引导熔体的流动方向；使分流道和塑件末端易于分离；快速冷却固化以防止熔融塑料充满型腔后倒流。 4、 冷料井 冷料井正对着主流道。理论上，冷料井的作用是用来储存在塑件冷却和推出过程中注塑机喷嘴处形成的熔体前锋冷料。也许冷料井更重要的作用是开模时帮助浇道凝料脱出浇口套。 塑件成型后，主流道 、分流道和浇口部分凝料将被遗弃。然而，分流道和浇口是影响塑件质量和成本的重要因素。 外文资料翻译 nts The Injection Molding Injection molding ( British Engish : Molding ) is a manufacturing process for producing parts form both thermoplastic and thermosetting plastic materials.Material is fed into a heated brarel, mixed, and forced into a mold cavity where it cools and hardens to configuration of the mold cavity. After a product is designed, usually by an industrial designer or an engineer, molds aer made by a moldmaker ( or a toolmaker ) from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a varitey of parts, from the smallest compenent to entire body panels of cars. As shown in Fig.2-1, injection molding machines consist of a material hopper, an injection ram of screw-type plunger, and a heating unit. They are also known as presses. They hold the molds in which the compenents are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with the higher figures used in determined by the projected area of the part being molded.This projected area is multiplied by a champ force of 2 to 8 tons for each square inch of the projected area. As a rule of thumb, 4 or 5 t/in2 can be used for most products. If the plastic material is very stiff, it will require more injection pressure to fill the mold, thus more clamp tonnage to hold the mold closed. The required force can also be determined by the material used and the size of the part, larger parts require higher clamping force. Actual injection molding is shown in Fig 2-2. Mold or die are the common terms used to describe the tooling used to produce plastic parts in molding. Traditionally, molds have been expensive to manufacture. They were usually only used in mass production where thousands of parts were being produced. Molds are typically constructed from hardened steel, pre-hardened steel, aluminium, and/or beryllium-copper alloy. The chioce of material to build a mold from is primarily one of economics. Steel molds generally cost more to construct, but their longer number of parts made before wearing out. Pre-hardened steel molds are less wear resistant and are used for lower volume requirements or large compenents. The steel hardness is tyoically 38-45 on the Rockwell-C scale ( HRC). Hardened steel molds are heat treated after nts machining. These are by far the superior in terms of wear resistance and lifespan. Typical hardness ranges between 50 to 60 Rockwell scale. Aluminium molds can cost substantially less , and when designed and machined with morden computerized equipment, can be economical for molding tens or even hundreds of thousands of parts. Beryllium copper is used in areas of the mold which require fast removal or area that see the most shear heat generated. The molds can be manufactured by either CNC or by using Electrical Discharge Machining processes. Standard two plates tooling: core and cavity are inserts in a mold base Family mold of 5 different parts. The mold consists of two primary compenents, the injection mold ( A plate ) and the ejector mold ( B plate ) , as shown in Fig. 2-3. Plastic resin enters the mold through a sprue in the injection mold, the sprue bush is to seal tightly against the nozzle of the injection barrel of the molding machine and allow molten plastic to flow from the barrel into the mold , also known as cavity. The sprue bush directs the molten plastic to the cavity images through channels that are machined into the faces of the A or B plates. These channels allow plastic to run along them, so they are referred to as runners. The molten plastic flows through the runner and enters one or more specialized gates and into the cavity geometry to form the desired part. The amount of resin required to fill the sprue, runner and cavities of a mold is a shot. Trapped air in the mold can escape through air vents that are grinded into the parting line of the mold. If the trapped air is not allowed to escape , it is compressed by the pressure of the incoming material and is squeezed into the corners of the cavity , where it prevents filling and causes other defects as well . The air can become so compressed that it ignites and burns the surrounding plastic material. To allow for removal
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