Qué es la máquina de moldeo por inyección - Una guía completa

In plastics processing, one of the most crucial pieces of equipment is the injection molding machine or extruder. With the help of a suitable plastic mold system, plastics can be processed into complex shapes.

This article will explore the fundamental aspects of injection molding machines, including their types, structures, composition, working principles, and key Application in the plastics processing industry.

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Injection molding machines, also known as injection molding machines or injection presses, are the main equipment for injection molding. Their function is to transform thermoplastic materials from granular raw materials into the final molded products, completing a cycle of melting, injection, pressure holding, and cooling in each step. Injection molding machines are widely used in various fields such as machinery parts, defense industry, telecommunications engineering, transportation, instrumentation industry, electronics and electrical engineering, aviation, construction, agriculture, medical, and daily life.

The working principle of an injection molding machine mainly includes the following steps:

Granular plastic is added to the injection molding machine.

The injection molding machine heats the plastic, turning it into a liquid state.

The molten plastic is injected into the mold under high pressure.

The plastic cools and solidifies inside the mold.

The mold is opened, and the molded product is removed.

Suitable for the production of small parts.

Suitable for the production of large parts.

It is electrically driven and suitable for production with high precision requirements.

The function of the injection system: The injection system is one of the most important components of an injection molding machine. There are generally three main types: plunger type, screw type, and screw pre-plasticizing plunger injection type. The screw type is the most widely used. Its function is to heat and plasticize a certain amount of plastic within a specified time during one cycle of the injection molding machine, and then inject the molten plastic into the mold cavity through the screw under certain pressure and speed. After injection, it maintains the shape of the molten material injected into the mold cavity. The injection system consists of a plasticizing device and a power transmission device. The plasticizing device of a screw-type injection molding machine mainly consists of a feeding device, barrel, screw, glue-filling assembly, and nozzle. The power transmission device includes the injection cylinder, the injection seat moving cylinder, and the screw drive device (melt motor).

The function of the mold closing system: The mold closing system ensures the mold closes, opens, and ejects the product. Simultaneously, after the mold closes, it supplies sufficient clamping force to resist the mold cavity pressure generated by the molten plastic entering the mold cavity, preventing mold gaps and resulting in undesirable product conditions. Hydraulic System: The hydraulic transmission system provides power to enable the injection molding machine to perform various actions required by the process, and meets the pressure, speed, and temperature requirements of each part of the machine. It mainly consists of various hydraulic components and auxiliary hydraulic components, with the oil pump and motor being the power source. Various valves control the oil pressure and flow rate to meet the various requirements of the injection molding process.

The electrical control system works in conjunction with the hydraulic system to achieve the injection molding machine’s process requirements (pressure, temperature, speed, time) and various programmed actions. It mainly consists of electrical and electronic components, instruments, heaters, and sensors. There are generally four control modes: manual, semi-automatic, fully automatic, and adjustable.

The heating system heats the barrel and injection nozzle. The injection molding machine barrel typically uses an electric heating coil as the heating device, installed externally and monitored by thermocouples in sections. Heat is conducted through the barrel wall to provide a heat source for material plasticization. The cooling system mainly cools the oil temperature; excessively high oil temperature can cause various malfunctions, so the oil temperature must be controlled. Another area requiring cooling is near the material outlet of the feed tube to prevent the raw material from melting at the outlet, which could prevent normal material feeding.

The lubrication system provides lubrication to moving parts of the injection molding machine, such as the moving platen, mold adjustment device, connecting rods, and injection unit. This reduces energy consumption and extends part life. Lubrication can be performed manually or automatically via electric lubrication.

The safety devices of the injection molding machine are primarily designed to protect personnel and equipment. They mainly consist of safety doors, safety baffles, hydraulic valves, limit switches, and photoelectric detection elements, achieving interlocking protection between electrical, mechanical, and hydraulic systems.

The monitoring system primarily monitors the injection molding machine’s oil temperature, material temperature, system overload, and process and equipment malfunctions, issuing indicators or alarms upon detecting abnormalities.

Injection molding machines play a vital role in the plastics molding industry. Some of the most practical and common uses include:

• Headlight housings, interior trim, bumpers, etc.
• Monitor casing, mouse, keyboard, USB data cable, etc.
• Water heater casing, induction cooker casing, rice cooker casing, etc.
• Disposable water cups, plastic stools, children’s toys, etc.
• PP rainwater harvesting module

Plastic processing refers to the manufacture of various parts, from simple to complex, using injection molding machines. Once a suitable machine with appropriate tonnage and mold system is selected, different plastic parts can be manufactured.

At Hualin, we use injection molding machines to process various PP rainwater harvesting modules, all customized to customer requirements. For any custom PP rainwater harvesting module needs, send an inquiry now.