注塑成型机的工作原理

Working principle of injection molding machine

注塑机的工作原理与打针用的注射器相似，它是借助螺杆（或柱塞）的推力，将已塑化好的熔融状态（即粘流态）的塑料注射入闭合好的模腔内，经固化定型后取得制品的工艺过程。

The working principle of the injection molding machine is similar to the injector used in the injection needle. It is an injection into a good mold cavity with the thrust of the screw (or plunger) into the closed mold cavity, and the process of obtaining the product after the solidification is fixed.

注射成型是一个循环的过程，每一周期主要包括：定量加料—熔融塑化—施压注射—充模冷却—启模取件。取出塑件后又再闭模，进行下一个循环。

Injection molding is a cycle process. Each cycle mainly includes: quantitative feeding, melting, plasticizing, pressure injection, mold filling, cooling and starting. After removing the plastic parts, the mold is closed again for the next cycle.

1.2 注塑机的结构

1.2 structure of injection molding machine

注塑机根据塑化方式分为柱塞式注塑机和螺杆式注塑机；按机器的传动方式又可分为液压式、机械式和液压—机械（连杆）式；按操作方式分为自动、半自动、手动注塑机。

Injection molding machine is divided into plunger injection molding machine and screw injection molding machine according to plasticizing mode. According to the machine transmission mode, it can be divided into hydraulic, mechanical and hydraulic mechanical (connecting rod); it can be divided into automatic, semi-automatic and manual injection molding machine according to operation mode.

（1）卧式注塑机：这是最常见的类型。其合模部分和注射部分处于同一水平中心线上，且模具是沿水平方向打开的。其特点是：机身矮，易于操作和维修；机器重心低，安装较平稳；制品顶出后可利用重力作用自动落下，易于实现全自动操作。目前，市场上的注塑机多采用此种型式。

(1) horizontal injection molding machine: This is the most common type. The clamping part and injection part are on the same horizontal centerline, and the die is opened horizontally. Its characteristics are: the fuselage is short, easy to operate and maintain; the machine center of gravity is low and the installation is more stable; after the product is ejecting, it can automatically drop by the action of gravity, and it is easy to realize full automatic operation. At present, the injection molding machine in the market mostly adopts this type.

（2）立式注塑机：其合模部分和注射部分处于同一垂直中心线上，且模具是沿垂直方向打开的。因此，其占地面积较小，容易安放嵌件，装卸模具较方便，自料斗落入的物料能较均匀地进行塑化。但制品顶出后不易自动落下，必须用手取下，不易实现自动操作。立式注塑机宜用于小型注塑机，一般是在60克以下的注塑机采用较多，大、中型机不宜采用。

(2) vertical injection molding machine: its clamping part and injection part are on the same vertical centerline, and the mold is opened along the vertical direction. Therefore, the utility model has the advantages of small footprint, easy placement of inserts, convenient loading and unloading of moulds, and the material falling into the self hopper can be plasticized evenly. But after the product is ejection, it is not easy to fall automatically. It must be removed by hand, so it is not easy to realize automatic operation. Vertical injection molding machine is suitable for small injection molding machine. Generally, there are more injection molding machines under 60 grams, and large and medium machine should not be used.

（3）角式注塑机：其注射方向和模具分界面在同一个面上，它特别适合于加工中心部分不允许留有浇口痕迹的平面制品。它占地面积比卧式注塑机小，但放入模具内的嵌件容易倾斜落下。这种型式的注塑机宜用于小机。

(3) angular injection molding machine: the injection direction and the die interface are on the same surface. It is especially suitable for the processing center part that is not allowed to leave the surface of the gate with the gate. It occupies a smaller area than horizontal injection molding machine, but the inserts in the mold tend to tilt down. This type of injection molding machine should be used for small machine.

（4）多模转盘式注塑机：它是一种多工位操作的特殊注塑机，其特点是合模装置采用了转盘式结构，模具围绕转轴转动。这种型式的注塑机充分发挥了注射装置的塑化能力，可以缩短生产周期，提高机器的生产能力，因而特别适合于冷却定型时间长或因安放嵌件而需要较多辅助时间的大批量塑制品的生产，但因合模系统庞大、复杂，合模装置的合模力往往较小，故这种注塑机在塑胶鞋底等制品生产中应用较多。

(4) multimode turntable injection molding machine: it is a special injection machine with multi position operation. Its characteristic is that the clamping device adopts a turntable structure, and the die revolves around the rotating shaft. This type of injection molding machine gives full play to the plasticizing ability of the injection device. It can shorten the production cycle and improve the production capacity of the machine. Therefore, it is especially suitable for the production of large quantities of plastic products with long setting time or more auxiliary time due to the placement of the parts. But because of the large and complex model system, the clamping force of the mold closing device is often small, so this injection molding machine is in plastic. There are many applications in the production of sole and other products.

一般注塑机包括注射装置、合模装置、液压系统和电气控制系统等部分。

General injection molding machine includes injection device, clamping device, hydraulic system and electrical control system.

注射成型的基本要求是塑化、注射和成型。塑化是实现和保证成型制品质量的前提，而为满足成型的要求，注射必须保证有足够的压力和速度。同时，由于注射压力很高，相应地在模腔中产生很高的压力（模腔内的平均压力一般在20~45MPa之间，见表1），因此必须有足够大的合模力。由此可见，注射装置和合模装置是注塑机的关键部件。

The basic requirements of injection molding are plasticization, injection and molding. Plasticization is the premise to achieve and guarantee the quality of molded products. In order to meet the requirements of molding, injection must ensure sufficient pressure and speed. At the same time, due to the high pressure of injection, high pressure is produced in the cavity (the average pressure in the die cavity is generally between 20~45MPa, see Table 1), so there must be a large enough clamping force. It can be seen that injection device and clamping device are the key parts of injection molding machine.