An injection molding machine, sometimes called an injection press, is basically a machine for making plastic products using the in-line injection molding method. It is made up of two main components, an injection unit and a molding unit. Injection molding uses heat to force hot plastic liquid (usually polyethylene) into the molds from a distance, much like a press setting up your own newspaper with a nozzle. In order to do this, it uses a vacuum, but an electric injection molding machine uses no vacuum.
The molding unit is equipped with a number of rollers, which apply continuous pressure to move the material into the desired shape, from either the clamping or transfer positions. Because they are held in place by clamps or pressure control screws, it is important that these parts are always in the correct position. This is done with the aid of hydraulic pistons, which apply rotary pressure to move the rollers along the mold line, ensuring that the rollers follow a perfectly straight path throughout the transfer position and onto the finished part. This ensures the quality of the end product, which is a factor for many industrial applications.
Because the design of every injection molding machine is unique, the products that can be produced are also limited. Each machine varies slightly depending on the size of the mold required and the materials to be pressed into it. In general, however, each machine produces a similar result: a plastic part that has been pressed directly into a substrate. The machine may use different types of plastic press, or it may use the same type of plastic press to transfer the plastic from the mold into a usable shape.
The most common parts that make up an injection molding machine are the clamping device and the slide assembly. A clamping unit typically has two pieces, the first containing the clamp itself, and the second holding the work piece into the clamp. The slide assembly is mounted on the clamping unit and contains the moving parts - the blade and knob, among others. In order to work, the two must be precisely synchronized. The clamps and slide are generally precision-built, and manufacturers ensure top performance by providing lifetime parts warranty and service agreement.
As mentioned earlier, there are two types of presses in injection molding machines: those that incorporate a rotary drum and those that do not. Rotary drums are used to speed up the mixing and molding operation, allowing manufacturers to press several plastic parts per hour. However, because they need to deal with stronger heat during the process, they are often more expensive than other types of presses. On the other hand, they are also the only press that can guarantee consistent results, as they are able to maintain a smooth and even pressure. Standard rotary drums are typically used in injection molding machines, but they are less common.
en
cn
