Injection molding machine, also known as an injection press. Injection Moldings is a manufacturing process for producing parts in large volume. It is most typically used in mass-production processes where the same part is being created thousands or even millions of times in succession. The injection molding machine converts granular or pelleted raw plastic into final molded parts through a melt, inject, pack, and cool cycle.
A typical injection molding machine consists of the following major components, as illustrated in picture below.
What’s advantages of Injection Molding
Increase production. Once the initial costs have been paid the price per unit during injection molded manufacturing is extremely low. The price also tends to drop drastically as more parts are produced.
Produces low scrap rates Relative to traditional manufacturing processes (like CNC machining) which cut away substantial percentages of an original plastic block or sheet.
Be repeatable Your production is going to be practically identical to the first one etc. Suitable for producing components of high volume for brand consistency.
Types of Injection Mouldings Machines Machines are classified primarily by the type of driving systems they use：Hydraulic, mechanical, electrical, or hybrid.
Hydraulic Hydraulic presses have historically been the only option available to molders until Nissei Plastic Industrial Co., LTD introduced the first all-electric injection molding machine in 1983. Hydraulic machines, although not nearly as precise, are the predominant type in most of the world, with the exception of Japan.
Mechanical Mechanical type machines use the toggle system for building up tonnage on the clamp side of the machine. Tonnage is required on all machines, so the clamp side of the machine does not open due to the injection pressure. If the tool half opens up it will create flash in the plastic product.
Electric The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption. Electric presses have been shown to be quieter, faster, and have a higher accuracy, however the machines are more expensive.
Hybrid (sometimes referred to as "Servo-Hydraulic") Hybrid injection moldeds machines claim to take advantage of the best features of both hydraulic and electric systems, but in actuality use almost the same amount of electricity to operate as an electric injection molding machine depending on the manufacturer.
Plastic Injection Processing Technologies
Non-marking injection technology: Traceless injection technology is a high-temperature mold injection technology that allows the mold to be quickly heated and cooled, and then uses a steam or high-pressure hot water acceleration control system to control the entire cold and hot molding process to achieve a perfect molding effect. This technology makes the resin flow in the mold cavity to the best state, avoiding the change of the material properties caused by the gradual cooling of the plastic during the injection and filling process, and the formation of various defects, such as fusion line, distortion, surface depression, and other different gases Marks, etc.
Micro-foaming co-injection technology: Combining the two technologies of micro-foam injection molding and co-injection allows the two technologies to complement each other. The foam layer manufactured through micro-foaming technology can reduce product weight, improve product size accuracy and reduce deformation, while the outer layer manufactured through co-injection technology can cover the rough foam layer, thereby improving the appearance of the product.
Microcellular foam injection: The use of physical foaming agent produces fine cells with even distribution and similar size, improving the consistency and uniformity of the cell structure, and making the product performance superior to those produced by other foaming technologies.
Micro-injection: Miniature injection molded parts generally refer to parts with plastic parts weighing less than 0.1g or less. The application range of such parts is very wide; for example, some micro-switches, micro-motors and sensors, gears, latches and transmission parts in clocks and watches, etc. have also largely replaced traditional metal parts with plastic. Besides, plastic can also be applied to miniature optical lenses, sensor discs, light guide plates, and display devices. Medical products are one of the potential markets. Specific examples include medical parts implanted in the human body or blood vessels, such as hearing aids and implant parts made of biodegradable plastic.
Ultra-refrigerated gas-assisted injection molding technology: This technology is based on gas-assisted injection molding technology and improved, which greatly shortens the production cycle by 40%, increases production efficiency, and improves the control of the wall thickness of hollow parts. It is suitable for manufacturing large hollow products. Ultra-refrigerated gas-assisted injection molding uses a set of specially designed heat converters, using liquid nitrogen as the refrigerant, freezing the nitrogen at room temperature, and high pressure to about minus 40 degrees to minus 120 degrees, and then injecting the frozen low temperature and high-pressure nitrogen into the glue Within pieces.
External pressure gas-assisted injection molding: External pressure gas-assisted injection molding technology is used to produce flat and thin injection parts with flawless surfaces and is especially suitable for products with large changes in plane and wall thickness supported by reinforcing ribs.
Plastic mixing: Plastic mixing is the mixing of two plastics at their melting temperature, and the resulting mixture has its unique material characteristics. This process helps to develop biodegradable materials and improve polymer properties.
Water-assisted injection molding technology: Water-assisted injection molding technology is a hollow product manufacturing technology. This technology uses the excellent heat absorption and heat conduction properties of water to accelerate the heat dissipation and cooling effect during the injection molding process, and can shorten the cooling time by up to 70%, thereby shortening the production cycle; also, the faster cooling rate makes the crystallization process in the plastic more even. Form uniform and fine crystals, thereby improving the physical properties of injection molded parts, with less shrinkage and warpage deformation.
Co-injection: The characteristic of co-injection technology lies in its sequential/simultaneous injection of two different but compatible plastic materials into the cavity to form the inner and outer layers of the product respectively. Products manufactured by this technology will have the characteristics of two constituent materials. The most popular application example is a plastic product with a hard inner layer but a soft rubber outer layer.
Multi-piece injection: A multi-part injection is to use two or more plastics to inject into one product.
Gas-assisted injection: Gas-assisted injection molding is to inject nitrogen into the product to make the product hollow.