With the widespread application of plastic products and their rapid growth in production, plastic machinery has become an important technical equipment in industries such as building materials, packaging, electronics, automobiles, petrochemicals, and machinery, leading to a surge in demand. Among these, injection molding machines, due to their excellent adaptability to processing various plastics, can mold complex-shaped, dimensionally precise, or densely textured plastic products with metal inserts in a single pass. Furthermore, their high production capacity and ease of automation have made them one of the fastest-growing and most produced types of plastic machinery. Statistics show that injection molding machines currently account for 20% to 30% of the total production of plastic molding equipment. While the plastic product processing industry is developing rapidly, competition within the industry is also becoming increasingly fierce. How to effectively reduce costs and improve product competitiveness has become a common concern for companies in the industry. In recent years, some domestic and foreign manufacturers have launched energy-saving products such as variable pump injection molding machines and all-electric injection molding machines. However, due to factors such as high equipment prices, high maintenance costs, and high usage requirements, their sales in the domestic market are not significant. More than 90% of the injection molding machines used by plastic processing enterprises in my country are still fixed-displacement pump injection molding machines. Therefore, adopting new technologies to carry out energy-saving retrofits on fixed-displacement pump injection molding machines is of greater practical significance. Variable frequency drives (VFDs) are a new type of technology that allows for flexible and convenient changes in motor speed. This enables fixed-displacement pumps to be simulated as variable-displacement pumps, achieving energy-saving retrofits. The Principle of VFD Energy-Saving Retrofits for Injection Molding Machines Currently, most injection molding machines use hydraulic transmission. Fixed-displacement pump injection molding machines use an electric motor to drive the pump, supplying oil to the hydraulic transmission system. Previously, hydraulic motors were directly connected to mains power and operated at the industrial frequency, meaning the pump's output flow rate could not change with load variations, maintaining a constant flow. Injection molding machine design has long pursued precision and high speed, with motor power typically designed based on the maximum power consumption of each action. However, in actual production, due to the surface precision requirements of products, high-speed, high-pressure molding is often unsuitable, leading to an overestimation of the injection molding machine's design power. In actual use, the average motor load is often only 40% to 60% of the design capacity, and in some cases even lower. This results in significant energy waste when the motor operates at the industrial frequency. VFD retrofits for fixed-displacement pump injection molding machines are based on these two reasons. The modified system can automatically track the working status, pressure, and flow signals of the injection molding machine itself. By controlling the speed of the hydraulic motor in real time and appropriately through the frequency converter, it adjusts the pump's output flow, ensuring that the actual oil supply of the pump remains consistent with the injection molding machine's flow requirements at any stage of operation. This minimizes the energy consumption of the motor throughout the load change process and essentially eliminates overflow. Furthermore, stopping the motor during non-operational periods further increases energy savings. Additionally, the application of a frequency converter improves the system's power factor, reduces reactive power losses in the hydraulic motor, and enhances the factory's power supply efficiency and grid quality. In conclusion, it is clear that frequency conversion energy-saving retrofitting of a fixed-displacement pump injection molding machine can bring significant energy-saving effects. [b][align=center]For more details, please click: Frequency Converter for Energy-Saving Retrofitting of Injection Molding Machines[/align][/b]