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| Learn about Injection Molding Machine (PART I) In the next several weeks, we will learn about injection molding machine together. Today, the article is about the basis knowledge of machine's structure and function. I. Brief Introduction of Injection Molding Machine Injection molding machine refers to the machine which transfers the thermoplastic plastics or thermosetting materials in to different types of plastic products through mould. Injection molding machine and mould are two main necessary parts during the process of injection molding. Different types injection molding machine have two basic functions: (1) heat the plastic to melting state; (2) apply high pressure to the melting plastic and intrude it into the mould II. Function and Structure of Injection Molding Machine Injection molding refers to use the pressure to intrude melted plastic into the closed mould through a heated barrel and take out the products when the mould opens. The mould closes again and plastic is intruded again, which forms a orderly and repeated process. The injection molding machine consists of injection unit, clamping unit, hydraulic drive unit, electric control unit, lubricating unit, heating and cooling unit and safety monitoring system. (1) Injection Unit Function of injection unit: injection unit is the main part of injection molding machine and there are mainly 3 kinds of injection unit- plunger type, screw type, screw pre-plastic plunger injection type. In a production cycle, the injection unit helps to heat the plastic material and intrude it into the mould through barrel at a certain pressure and speed, which is called an injection motion. Formation of injection unit: plasticizing device and drive device (2) Clamping Unit Function of clamping unit: clamping unit works to assure the mold close and open in the right way and inject products. In the same time, it gives the mould enough clamping force when the mould closes, which keeps balance against the force the melting plastics bring when intruded into the mould. This will help to assure the mould close and cut down defective rate. Formation of clamping unit: clamping unit consists of clamping device, mould adjusting mechanism, ejection mechanism, fix template and rear template, moving template, cylinder and safety protection system. (3) Hydraulic Drive Unit Hydraulic drive unit offers motive power for every motions of the whole production cycle and helps to assure the appropriate pressure, speed and pressure. It is made up of hydraulic parts and hydraulic auxiliary element, among which the motor and oil pump are the main power resources. The valves control the hydraulic pressure and flow to satisfy the production requirements of injection molding process. (4) Electric Control Unit Electric control unit cooperates with hydraulic unit to realize the requirements of whole injection molding process and all kinds of motions. It consists of electronic components, meters, heaters, sensors. There are mainly four control modes: manual mode, semi-manual mode, full-automatic mode, adjustment mode. (5) Heating and Cooling Unit The heating unit mainly aims at heating the barrel and injection nozzle. The barrel normally uses hot runners as hearing device, which are set around the barrel and monitored by thermocouple. The cooling unit aims at cooling the oil temperature. If the oil temperature is too high, the machine will break down in different ways. The material pipe outlet is another place that should be cooled. This prevents the material pipe from melting, which assures the material melt normally. (6) Lubricating Unit Lubricating unit refers to the circuit to offer oil to moving template, mould adjusting device connecting rod hinge and other moving parts. It helps reduce the power consumption and prolong the unit life. The lubrication can be regular manual lubrication or automatic electric lubrication. (7) Safety Monitoring System Safety monitoring system is aimed to protect operators, which consists of safe door, hydraulic valve, limit switch, photoelectric detection element. It will set alert when unusual conditions appear to the oil temperature, material temperature, system overload and other device breakdown. This is all for this week. |
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