1.1 Injection molding machines can be divided into two-platen machines, three-platen machines and all-electric injection molding machines
1.1.1 Two-platen machines are mainly used for large products, and three-platen machines are more universal
Injection molding machines (abbreviated as injection machines or injection molding machines) are the main molding equipment that uses plastic molding molds to make thermoplastic plastics or thermosetting materials into plastic products of various shapes. The working principle of an injection molding machine is similar to that of a syringe. It uses the thrust of a screw (or plunger) to inject plasticized molten state (i.e., viscous flow state) plastic into a closed mold cavity, and then obtains the product after solidification and shaping. Injection molding is a cyclic process, and each cycle mainly includes: quantitative feeding - melt plasticization - pressure injection - mold filling and cooling - mold opening and part removal
Injection molding machines are mainly divided into three categories according to the driving mode: hydraulic, all-electric and electro-hydraulic hybrid.
Hydraulic injection molding machines have the characteristics of large clamping force, long clamping and holding time, but their process stability and production accuracy are low, making it difficult to perform multi-stage injection in a short time; all-electric injection molding machines originated in Japan, replacing hydraulic cylinders and hydraulic valves with servo motors and ball screws, with stable injection performance, precise and fast control, high production efficiency, low pollution noise, energy saving and environmental protection, especially suitable for small and medium-sized high-speed precision injection molding, but expensive and high maintenance costs; electro-hydraulic hybrid injection molding machines have the characteristics of the first two, with large clamping force and injection pressure, precise control, fast action, complete functions, and moderate cost. Among them, hydraulic injection molding machines can be divided into three-platen machines and two-platen machines.
In the development of injection molding machines, with the demand for large plastic parts in downstream application fields such as automobiles, the clamping force tonnage of injection molding machines continues to increase. For large-tonnage equipment, two-platen machines (direct pressure clamping) are generally used. For general plastic products, traditional three-plate injection molding machines (crankshaft clamping) are mainly selected.
1.1.2 Electric injection molding machines are suitable for small parts, high precision, and high-efficiency processing scenarios
Precision, high efficiency, energy saving, and intelligence are the mainstream trends of modern injection molding technology. Compared with traditional hydraulic injection molding machines, electric injection molding machines have outstanding advantages. According to micro injection molding, the advantages of electric injection molding machines are as follows:
1) Since electric injection molding machines use servo motors, their energy utilization rate can reach more than 95%, so they can save 25%-60% energy compared to full hydraulic injection molding machines.
2) Stable injection performance. The dynamic technical parameters of full hydraulic injection molding machines are affected by changes in hydraulic oil temperature and are prone to fluctuations. In contrast, the dynamic technical parameters of full electric injection molding machines are basically not disturbed by external factors.
3) Water saving. Since full electric injection molding machines do not use hydraulic oil, they only need cooling water at the feeding port. Therefore, compared with hydraulic injection molding machines with load-sensitive pumps, the use of cooling water can be reduced by 70%, and compared with hydraulic injection molding machines with ordinary quantitative pumps, the use of cooling water can be reduced by 90%. With the advantages of high speed, high efficiency and high precision, all-electric injection molding machines are more suitable for processing electronic, electrical, electrical appliances and other high value-added products, especially for the injection molding of small parts, which shows its advantages of high performance and high precision injection molding.
Electric injection molding machines have the advantages of clean and energy-saving, flexible and easy to control, high precision and molding efficiency, and have significant advantages in industries such as 3C and medical that have high requirements for working environment and precision. With the widespread application of high-precision parts and the reduction of the manufacturing cost of electric injection molding machines, electric injection molding machines are expected to gradually expand their market share in the future.
