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门把手注塑模具设计,门把手,注塑,模具设计 2 Injection molding machine From Plastics Wiki, free encyclopedia Injection molding machines consist of two basic parts, an injection unit and a clamping unit. Injection molding machines differ in both injection unit and clamping unit. The name of the injection molding machine is generally based on the type of injection unit used. 2.1 Types of injection molding machines Machines are classified primarily by the type of driving systems they use: hydraulic, electric, or hybrid. 2.1.1 Hydraulic Hydraulic presses have historically been the only option available to molders until Nissei Plastic Industrial Co., LTD introduced the first all-electric injection molding machine in 1983. The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption and also addresses some of the environmental concerns surrounding the hydraulic press. 2.1.2 Electric Electric presses have been shown to be quieter, faster, and have a higher accuracy, however the machines are more expensive. 2.1.3 Hybrid Hybrid injection molding machines take advantage of the best features of both hydraulic and electric systems. Hydraulic machines are the predominant type in most of the world, with the exception of Japan. 2.2 Injection unit The injection unit melts the polymer resin and injects the polymer melt into the mold. The unit may be: ram fed or screw fed. The ram fed injection molding machine uses a hydraulically operated plunger to push the plastic through a heated region. The high viscosity melt is then spread into a thin layer by a "torpedo" to allow for better contact with the heated surfaces. The melt converges at a nozzle and is injected into the mold. Reciprocating screw A combination melting, softening, and injection unit in an injection molding machine. Another term for the injection screw. Reciprocating screws are capable of turning as they move back and forth. The reciprocating screw is used to compress, melt, and convey the material. The reciprocating screw consists of three zones (illustrated below): · feeding zone · compressing zone · metering zone While the outside diameter of the screw remains constant, the depth of the flights on the reciprocating screw decreases from the feed zone to the beginning of the metering zone. These flights compress the material against the inside diameter of the barrel, which creates viscous (shear) heat. This shear heat is mainly responsible for melting the material. The heater bands outside the barrel help maintain the material in the molten state. Typically, a molding machine can have three or more heater bands or zones with different temperature settings. Injection molding reciprocating screw An extruder-type screw rotates within a cylinder, which is typically driven by a hydraulic drive mechanism. Plastic material is moved through the heated cylinder via the screw flights and the material becomes fluid. The injection nozzle is blocked by the previous shot, and this action causes the screw to pump itself backward through the cylinder. (During this step, material is plasticated and accumulated for the next shot.) When the mold clamp has locked, the injection phase takes place. At this time, the screw advances, acting as a ram. Simultaneously, the non-return valve closes off the escape passages in the screw and the screw serves as a solid plunger, moving the plastic ahead into the mold. When the injection stroke and holding cycle is completed, the screw is energized to return and the non-return valve opens, allowing plastic to flow forward from the cylinder again, thus repeating the cycle. 2.2.1 Feed hopper The container holding a supply molding material to be fed to the screw. The hopper located over the barrel and the feed throat connects them. 2.2.2 Injection ram The ram or screw that applies pressure on the molten plastic material to force it into the mold cavities. 2.2.3 Injection screw The reciprocating-screw machine is the most common. This design uses the same barrel for melting and injection of plastic. The alternative unit involves the use of separate barrels for plasticizing and injecting the polymer. This type is called a screw-preplasticizer machine or two-stage machine. Plastic pellets are fed from a hopper into the first stage, which uses a screw to drive the polymer forward and melt it. This barrel feeds a second barrel, which uses a plunger to inject the melt into the mold. Older machines used one plunger-driven barrel to melt and inject the plastic. These machines are referred to as plunger-type injection molding machines. 2.2.4 Barrel Barrel is a major part that melts resins transmitted from hopper through screws and structured in a way that can heat up resins to the proper temperature. A band heater, which can control temper atures in five sections, is attached outside the barrel. Melted resins are supplied to the mold passing through barrel head, shot-off nozzle, and one-touch nozzle. 2.2.5 Injection cylinder Hydraulic motor located inside bearing box, which is connected to injection cylinder load, rotates screw, and the melted resins are measures at the nose of screw. There are many types of injection cylinders that supply necessary power to inject resins according to the characteristics of resins and product types at appropriate speed and pressure. This model employs the double cylinder type. Injection cylinder is composed of cylinder body, piston, and piston load. 2.3 Clamping unit The clamping unit holds the mold together, opens and closes it automatically, and ejects the finished part. The mechanism may be of several designs, either mechanical, hydraulic or hydromechanical. Toggle clamps - a type clamping unit include various designs. An actuator moves the crosshead forward, extending the toggle links to push the moving platen toward a closed position. At the beginning of the movement, mechanical advantage is low and speed is high; but near the end of the stroke, the reverse is true. Thus, toggle clamps provide both high speed and high force at different points in the cycle when they are desirable. They are actuated either by hydraulic cylinders or ball screws driven by electric motors. Toggle-clamp units seem most suited to relatively low-tonnage machines. Two clamping designs: (a) one possible toggle clamp design (1) open and (2) closed; and (b) hydraulic clamping (1) open and (2) closed. Tie rods used to guide movuing platens not shown. Hydraulic clamps are used on higher-tonnage injection molding machines, typically in the range 1300 to 8900 kN (150 to 1000 tons). These units are also more flexible than toggle clamps in terms of setting the tonnage at given positions during the stroke. Hydraulic Clamping System is using the direct hydraulic clamp of which the tolerance is still and below 1 %, of course, better than the toggle system. In addition, the Low Pressure Protection Device is higher than the toggle system for 10 times so that the protection for the precision and expensive mold is very good. The clamping force is focus on the central for evenly distribution that can make the adjustment of the mold flatness in automatically. Hydromechanical clamps - clamping units are designed for large tonnages, usually above 8900 kN (1000 tons); they operate by (1) using hydraulic cylinders to rapidly move the mold toward closing position, (2) locking the position by mechanical means, and (3) using high pressure hydraulic cylinders to finally close the mold and build tonnage. 2.3.1 Injection mold There are two main types of injection molds: cold runner (two plate and three plate designs) and hot runner – the more common of the runnerless molds. 2.3.2 Injection platens Steel plates on a molding machine to which the mold is attached. Generally, two platens are used; one being stationary and the other moveable, actuated hydraulically to open and close the mold. It actually provide place to mount the mould. It contains threaded holes on which mould can be mounted using clamps. 2.3.3 Clamping cylinder A device that actuates the chuck through the aid of pneumatic or hydraulic energy. 2.3.4 Tie Bar Tie bars support clamping power, and 4 tie bars are located between the fixing platen and the support platen. 3 Injection mould From Wikipedia, the free encyclopedia Mold A hollow form or cavity into which molten plastic is forced to give the shape of the required component. The term generally refers to the whole assembly of parts that make up the section of the molding equipment in which the parts are formed. Also called a tool or die. Moulds separate into at least two halves (called the core and the cavity) to permit the part to be extracted; in general the shape of a part must be such that it will not be locked into the mould. For example, sides of objects typically cannot be parallel with the direction of draw (the direction in which the core and cavity separate from each other). They are angled slightly; examination of most household objects made from plastic will show this aspect of design, known as draft. Parts that are "bucket-like" tend to shrink onto the core while cooling and, after the cavity is pulled away, are typically ejected using pins. Parts can be easily welded together after moulding to allow for a hollow part (like a water jug or doll's head) that couldn't physically be designed as one mould. More complex parts are formed using more complex moulds, which may require moveable sections, called slides, which are inserted into the mould to form particular features that cannot be formed using only a core and a cavity, but are then withdrawn to allow the part to be released. Some moulds even allow previously moulded parts to be re-inserted to allow a new plastic layer to form around the first part. This system can allow for production of fully tyred wheels. Traditionally, moulds have been very expensive to manufacture; therefore, they were usually only used in mass production where thousands of parts are being produced. Molds require: Engineering and design, special materials, machinery and highly skilled personnel to manufacture, assemble and test them. Cold-runner mold Cold-runner mold Developed to provide for injection of thermoset material either directly into the cavity or through a small sub-runner and gate into the cavity. It may be compared to the hot-runner molds with the exception that the manifold section is cooled rather than heated to maintain softened but uncured material. The cavity and core plates are electrically heated to normal molding temperature and insulated from the cooler manifold section. 3.1.1 Types of Cold Runner Molds There are two major types of cold runner molds: two plate and three plate. 3.1.2 Two plate mold A two plate cold runner mold is the simplest type of mold. It is called a two plate mold because there is one parting plane, and the mold splits into two halves. The runner system must be located on this parting plane; thus the part can only be gated on its perimeter. 3.1.3 Three plate mold A three plate mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. Since the mold has two parting planes, the runner system can be located on one, and the part on the other. Three plate molds are used because of their flexibility in gating location. A part can be gated virtually anywhere along its surface. 3.1.4 Advantages The mold design is very simple, and much cheaper than a hot runner system. The mold requires less maintenance and less skill to set up and operate. Color changes are also very easy, since all of the plastic in the mold is ejected with each cycle. 3.1.5 Disadvantages The obvious disadvantage of this system is the waste plastic generated. The runners are either disposed of, or reground and reprocessed with the original material. This adds a step in the manufacturing process. Also, regrind will increase variation in the injection molding process, and could decrease the plastic's mechanical properties. 3.1.6 Hot runner mold Hot-runner mold - injection mold in which the runners are kept hot and insulated from the chilled cavities. Plastic freezeoff occurs at gate of cavity; runners are in a separate plate so they are not, as is the case usually, ejected with the piece. Hot runner molds are two plate molds with a heated runner system inside one half of the mold. A hot runner system is divided into two parts: the manifold and the drops. The manifold has channels that convey the plastic on a single plane, parallel to the parting line, to a point above the cavity. The drops, situated perpendicular to the manifold, convey the plastic from the manifold to the part. 3.1.7 Types of Hot Runner Molds There are many variations of hot runner systems. Generally, hot runner systems are designated by how the plastic is heated. There are internally and externally heated drops and manifolds. 3.1.8 Externally heated hot runners Externally heated hot runner channels have the lowest pressure drop of any runner system (because there is no heater obstructing flow and all the plastic is molten), and they are better for color changes none of the plastic in the runner system freezes. There are no places for material to hang up and degrade, so externally heated systems are good for thermally sensitive materials. 3.1.9 Internally heated hot runners Internally heated runner systems require higher molding pressures, and color changes are very difficult. There are many places for material to hang up and degrade, so thermally sensitive materials should not be used. Internally heated drops offer better gate tip control. Internally heated systems also better separate runner heat from the mold because an insulating frozen layer is formed against the steel wall on the inside of the flow channels. 3.1.10 insulated hot runners A special type of hot runner system is an insulated runner. An insulated runner is not heated; the runner channels are extremely thick and stay molten during constant cycling. This system is very inexpensive, and offers the flexible gating advantages of other hot runners and the elimination of gates without the added cost of the manifold and drops of a heated hot runner system. Color changes are very easy. Unfortunately, these runner systems offer no control, and only commodity plastics like PP and PE can be used. If the mold stops cycling for some reason, the runner system will freeze and the mold has to be split to remove it. Insulated runners are usually used to make low tolerance parts like cups and frisbees. 3.1.11 Disadvantages Hot-runner mold is much more expensive than a cold runner, it requires costly maintenance, and requires more skill to operate. Color changes with hot runner molds can be difficult, since it is virtually impossible to remove all of the plastic from an internal runner system. 3.1.12 Advantages They can completely eliminate runner scrap, so there are no runners to sort from the parts, and no runners to throw away or regrind and remix into the original material. Hot runners are popular in high production parts, especially with a lot of cavities. Advantages Hot Runner System Over a Cold Runner System include: · no runners to disconnect from the molded parts · no runners to remove or regrind, thus no need for process/ robotics to remove them · having no runners reduces the possibility of contamination · lower injection pressures · lower clamping pressure · consistent heat at processing temperature within the cavity · cooling time is actually shorter (as there is no need for thicker, longer-cycle runners) · shot size is reduced by runner weight · cleaner molding process (no regrinding necessary) · nozzle freeze and sprue sticking issues eliminated 中文翻译 注塑模具设计与制造 2 注射机 选自《维基百科》 注射机由两个基本部分组成，注射装置和夹紧装置。注射机在注射装置和夹紧装置上各不相同。注射机的名称一般是根据所用注塑单位的类型来定的。 2.1 注射机的种类 注射机主要是由他们使用的驱动系统类型分类的：分为液压，电动，或混合动力。 2.1.1 液压动力机 一直以来注射机都是用液压动力的，直到日精塑料工业有限公司在1983推出了第一款全电动注射机。电动压力机，也被称为电机技术（EMT），降低了运行成本，降低能源消耗，也解决了一些围绕液压机的环境问题。 2.1.2 电动机 事实证明电动压力机更安静，速度更快，并具有更高的精度，但机器更昂贵。 2.1.3 混合动力 混合动力注射机拥有液压和电气系统，性能比较好。现在除了日本，液压动力注射机是世界上最主要的类型。 2.2 注射装置 注射装置熔化聚合物树脂并将聚合物熔体注入模具中。该装置可能是：冲压式或者螺旋式的。 柱塞式注射机使用液压操作柱塞将塑料通过加热区域推动高粘度的熔体，然后形成薄薄的一层“鱼雷”，以便更好地与受热面接触。熔体在喷嘴处受压并注入模具中。 往复式螺杆组合融化、软化，注射装置注射成型。往复式螺杆是注射螺杆的另一个术语。往复式螺杆能够使他们来回移动。 往复式螺杆用于压缩、熔化和输送物料。往复螺杆由三个区域组成（如下所示）： · 进料区 · 压缩区 · 测量区 当螺杆的外径保持恒定时，往复式螺杆上的螺纹的深度从进料区到计量区的开始减小。这些螺纹和筒的内径材料相互压缩，从而产生粘性（剪切）热。这种剪切热主要是熔化材料。桶外的加热带帮助保持熔融状态下的物料。通常情况下，注射机可以有三个或更多的加热器带或带不同的温度装置。 注塑往复式螺杆挤出机螺杆在滚筒内旋转，通常由液压驱动机构驱动。塑料材料是通过加热气缸通过螺杆旋转熔化材料成为流体。喷油嘴被上一个步骤堵塞，这个动作使螺杆通过泵反向泵入。（在这一步中，物料的塑化，为下一个步骤。积累）当模具夹具已锁定，注射过程发生。此时，螺杆前进，完成一个冲程。同时，止回阀关闭螺杆中的溢流通道，螺杆作为固体柱塞，将塑料向前移动到模具中。当注射行程和保持循环完成后，螺杆被通电返回，止回阀打开，使塑料再次从气缸向前流动，从而重复循环。 2.2.1 进料槽 容器保持供给到螺杆的熔融原料。 位于机筒上方的料斗和进料口连接它们。 2.2.2 注射机 将熔化塑料材料上施加压力注入模具型腔的机器。 2.2.3 注射螺杆 往复式螺杆机是最常见的。 该设计使用相同的进料筒来熔化和注入塑料。 替代单元涉及使用单独的桶来塑化和注入聚合物。这种类型称为螺杆预增塑机或双级机。 塑料颗粒第一阶段从料斗进料，其使用螺杆将聚合物向前驱动并熔化。 该桶供给第二个料斗，其使用柱塞将熔体注入模具中。 较旧的机器使用一个柱塞驱动的桶来熔化和注入塑料。 这些机器被称为柱塞型注射机。 2.2.4 进料斗 桶是一个主要部分,可以加热树脂到适当的温度，从料斗通过螺丝和结构熔化。一个带热水器，可五段温度控制，连接外筒。熔融树脂提供给模具通过料斗，射出喷嘴，和一个触摸喷嘴。 2.2.5 注射缸 液压马达位于轴承箱内，连接喷油缸负荷，旋转螺杆，熔融树脂在螺杆的前端进行测量。有许多类型的注射筒提供必要的力量注入树脂根据树脂和产品类型的特点，在适当的速度和压力。该模型采用双缸式。喷油缸由缸体、活塞和活塞载荷组成。 2.3 夹紧装置 夹紧装置是将模具固定在一起，自动打开和关闭，并推出成品塑件。 该机构可以是机械，液压或液压机械的几种设计。 切换夹具-一个类型夹紧装置包括各种设计。执行器向前移动十字头，延伸拨动杆，使移动压板朝关闭位置移动。在运动开始时，机械的优势低，速度快，但接近结束的行程，机械的优势很明显。因此，当需要时，开关夹具在循环中的不同点处提供高速度和高压。他们是由液压缸或滚珠丝杠驱动电机驱动。 切换夹具比较适合于相对较低吨位的机器。 两个夹紧装置：（a）一个是切换夹具装置（1）打开和（2）关闭；（b）另外一个是液压夹紧（1）打开，（2）关闭。 用于引导未示出的移动压板的拉杆。 液压夹具用于高吨位注射机，通常在1300至8900 kN（150至1000吨）范围内。 这些装置也比切换夹具在设定位置时的吨位更灵活。 液压夹紧系统正在使用公差仍然低于1％的直接液压夹，当然比切换装置系统更好。 此外，低压保护装置比切换装置系统高10倍，使保护精度高，当然价格会更高。 夹紧力集中在中心，均匀分布，可以自动调整模具平面度。 液压夹具的夹紧装置设计的大吨位，通常超过8900千牛（1000吨）；;他们通过( 1 )使用液压缸快速移动模具走向关闭位置, ( 2 )通过机械手段锁定位置, ( 3)使用高压液压缸来最终关闭模具来制造吨位。 2.3.1 注塑模具 注塑模具主要有两种类型：冷流道（两板和三板的设计）和热流道–比较常见的无流道模具。 2.3.2 注射挡板 连接模具的成型机的钢板。一般来说，使用两个挡板；一是固定的，另一个是可移动的，液压地驱动以打开和关闭模具。它实际上提供了安装模具的地方。模具可以使用夹具安装在模具上。 2.3.3 夹紧缸 一种装置，驱动卡盘通过气动或液压能源援助。 2.3.4 连接杆 连接杆支撑夹紧力，4个拉杆位于固定压板和支承压板之间。 3 注射模具 选自《维基百科》 模具一种中空形状或空腔，熔融塑料被迫向其中形成所需部件的形状。这个术语一般是指组成零件的成型设备的零件的整个装配, 也称为工具或模具。 模具分为至少两半(称为型芯和型腔) ,以允许提取零件，通常,零件的形状一定不能被锁定在模具中。例如，物体的侧面通常不能与拉伸方向平行（型芯和型腔相互分离的方向）。他们略有角度; 对塑料制成的大多数家居用品的检查将显示设计的这一方面，称为草案。“桶状”的部件倾向于在冷却时收缩到芯上，并且在空腔被拉开之后，通常使用销来推出。以便可以将物理上不能设计成一个模具的中空部分（如水壶或玩偶的头部）的零件可以在模制后很容易地焊接在一起。 更复杂的部分是使用更复杂的模具，这可能需要可移动的部分，称为滑块，这是插入到模具，形成不能仅使用芯部和空腔形成的特定特征，但然后撤回允许部分被释放。有些模具甚至允许先前模制的部件重新插入，以允许在第一部分周围形成新的塑性层。该系统可以允许生产的全轮胎车轮。 通常，模具制造成本非常昂贵，因此，它们通常只用于大规模大批量的生产。 模具要求：工程设计，特殊材料，机械和高技能的人员来制造，组装和测试它们。 冷流道模具 冷流道模具用于将热固性材料直接注入型腔或通过小流道和浇口进入腔。可以将其与热流道模具进行比较，它是多段冷却而不是加热以保持软化但未固化的材料。 空腔和芯板电加热到正常模制温度并与冷却器管部分绝缘。 3.1.1 冷流道模具的类型 冷流道模具主要有两种：两板模和三板模。 3.1.2 两板模 两板冷流道模具是最简单的模具。 它被称为双板模具，因为有一个分型平面，模具分成两半。 流道系统必须位于该分型面上，因此该部件只能在其周边处被选通。 3.1.3 三板模 三板模具与两块板的不同之处在于它具有两个分离平面，并且当塑件被弹出时，模具分成三个部分。 由于模具具有两个分型面，所以浇注系统可以分别在两个分型面上， 由于其灵活的浇口位置，使用三个平板模具可以使塑件在其表面几乎没有浇口疤。 3.1.4 优势 模具设计非常简单，而且比热流道系统便宜得多。模具需要较少的维护和较少的技能设置和操作。颜色变化也很容易，因为模具中的所有塑料都可以在每个循环中加染料。 3.1.5 劣势 该系统的明显缺点是废塑料产生。 塑料是用原始材料处理或重新处理和再处理。 这增加了制造过程的一个步骤。 此外，再研磨会增加注射成型过程的变化，并且可能降低塑料的力学性能。 3.1.6 热流道模具 热流道模具注塑模具，其中的热流道保持热和绝缘的冷却腔。 塑性自由度发生在型腔，塑料是在一个单独的挡板，所以他们不像通常一样,用这块板弹出。 热流道模具是两板模具，在模具的一半内部具有加热流道系统。 热流道系统分为两部分：热流道板和热喷嘴。 热流道板具有将平行于分型线的单个平面上的塑料输送到空腔上方的通道。 垂直于热流道板定位的热喷嘴将塑料从热流道板传送到塑件。 3.1.7 热流道模具类型 热流道系统有许多变化。一般来说，热流道系统由塑料的加热方式来指定。有内部和外部加热热喷嘴和热流道板。 3.1.8 外部加热热流道 外部加热的热流道通道的压力下降最小的任何流道系统(因为没有加热器阻塞流动和所有的塑料都是熔融状态),他们的颜色变换