The function of the injection system: The injection system is one of the most important components of the injection molding machine. Generally, there are three main forms: plunger type, screw type, and screw preplasticized plunger injection type. At present, the most widely used is the screw type. Its function is that in a cycle of the plastic injection machine, a certain amount of plastic can be heated and plasticized within a specified time, and the molten plastic can be injected into the mold cavity through a screw under a certain pressure and speed. After the injection, the molten material injected into the mold cavity is kept in shape.
Composition of the injection system: The injection system consists of a plasticizing device and a power transmission device.
The plasticizing device of the screw injection molding machine is mainly composed of a feeding device, a barrel, a screw, and a nozzle. The power transmission device includes an injection cylinder, an injection seat moving cylinder, and a screw drive device (melting motor).
(2) Mold clamping system
The role of the clamping system: the role of the clamping system is to ensure that the mold is closed, opened and ejected products. At the same time, after the mold is closed, sufficient clamping force is provided to the mold to resist the cavity pressure generated by the molten plastic entering the mold cavity, and prevent the mold from opening seams, resulting in a bad status of the product.
The composition of the mold clamping system: the mold clamping system is mainly composed of a mold clamping device, a mold adjustment mechanism, an ejection mechanism, a front and rear fixed template, a movable template, a mold clamping cylinder and a safety protection mechanism.
(3) Hydraulic system
The function of the hydraulic transmission system is to realize the injection molding machine to provide power according to the various actions required by the process, and to meet the requirements of pressure, speed, temperature, etc. required by each part of the injection molding machine. It is mainly composed of various hydraulic components and hydraulic auxiliary components, among which the oil pump and the motor are the power source of the injection molding machine. Various valves control the oil pressure and flow rate to meet the requirements of the injection molding process.
(4) Electrical control system
The electrical control system and the hydraulic system are reasonably coordinated to realize the process requirements (pressure, temperature, speed, time) and various program actions of the injection machine. It is mainly composed of electrical appliances, electronic components, meters, heaters, sensors, etc. There are generally four control modes, manual, semi-automatic, fully automatic, and adjustment.
(5) Heating/cooling system
The heating system is used to heat the barrel and the injection nozzle. The barrel of the injection molding machine generally uses an electric heating ring as a heating device, which is installed on the outside of the barrel and is detected in sections by a thermocouple. The heat conducts heat conduction through the wall of the cylinder to provide a heat source for the plasticization of the material; the cooling system is mainly used to cool the oil temperature. Excessive oil temperature will cause a variety of faults, so the oil temperature must be controlled. The other location that needs to be cooled is near the feeding port of the feed pipe to prevent the raw material from melting at the feeding port, causing the raw material to fail to be fed normally.
(6) Lubrication system
The lubrication system is a circuit that provides lubrication conditions at the relative moving parts of the injection molding machine's movable template, mold adjustment device, connecting rod hinge, etc., in order to reduce energy consumption and increase the life of parts. Lubrication can be regular manual lubrication or Automatic electric lubrication;
(7) Safety protection and monitoring system
The safety device of the injection molding machine is mainly used to protect the safety of people and machines. It is mainly composed of safety doors, hydraulic valves, limit switches, photoelectric detection elements, etc., to achieve electrical-mechanical-hydraulic interlock protection.
The monitoring system mainly monitors the oil temperature, material temperature, system overload, and process and equipment failures of the injection molding machine, and indicates or alarms when abnormal conditions are found.
2022-02-25