(1) The structure of the injection molding machine
An injection molding machine is usually composed of an injection system, a clamping system, a hydraulic transmission system, an electrical control system, a lubrication system, a heating and cooling system, and a safety monitoring system.
1. Injection system
The role of the injection system: the injection system is one of the most important components of the injection molding machine, generally including plunger type, screw type, screw pre-plastic plunger injection
Three main forms of shooting. The screw type is currently the most widely used. 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 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, a rubber component, and a nozzle. The power transmission device includes an injection oil cylinder, an injection seat moving oil 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 supplied 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 poor status of the product.
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 the 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 sources 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
The electrical control system and the hydraulic system are reasonably coordinated to realize the process requirements (pressure, temperature, speed, time) and various
Program action. 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
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 cylinder wall 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 for the relative moving parts of the injection molding machine's movable template, mold adjustment device, connecting rod machine hinge, injection table, etc., in order to reduce energy consumption and increase the life of parts. Lubrication can be regular manual lubrication. It can also be automatic electric lubrication;
7. Safety monitoring
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 door, safety baffle, hydraulic valve, limit switch, photoelectric detection element, etc., to realize electric-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.
(2) Working principle of injection molding machine
The injection molding machine is a special plastic molding machine. It uses the thermoplasticity of the plastic. After it is heated and melted, it is quickly poured into the mold cavity by high pressure. After a period of pressure and cooling, it becomes a plastic product of various shapes.
