For the plastic product industry, power consumption is the main part of its production cost, and the injection molding machine is one of the main energy-consuming equipment in the plastic product factory. Therefore, reducing the energy consumption of the injection molding machine has become the key for the injection molding industry to reduce costs and improve product competitiveness Effective Ways.

At present, most of the injection molding machines are hydraulic transmission injection molding machines, and the power in the hydraulic transmission system is provided by the motor driving the oil pump. During the injection molding cycle, the flow rate and pressure required by the injection molding machine in different processes are different, and flow and pressure required by different processes must be adjusted by means of flow valves and pressure valves. The load of the hydraulic system varies greatly. Since the fixed displacement pump cannot adjust the output power, the excess energy can only be consumed in the baffle plate, oil leakage, and oil temperature rise. This not only aggravates the wear of various valves, but also causes excessive oil temperature, excessive motor noise, and shortened mechanical life. And usually in the design, the designed capacity of the user’s oil pump motor is much higher than the actual need, and there is a phenomenon of “big horses and small carts”, resulting in a large waste of electric energy. Therefore, it is of great significance to promote the application of AC frequency conversion speed control devices in injection molding machines to reduce energy waste.

Application of VFD in Injection

Advantages of using frequency converters in injection molding machines:

1. Energy saving
The three sets of asynchronous AC motors usually used in injection molding machines cannot change the speed, and the quantitative vane pump driven by them cannot change the flow rate of the output hydraulic oil. When the injection molding machine is operating at a low speed, the excess flow flows back to the oil tank through the overflow valve, resulting in a large loss of energy. The frequency converter can adjust the speed of the motor according to the instructions of the control system, so that the flow rate of the hydraulic oil output by the vane pump can be changed according to the action speed of the injection molding machine, which reduces the energy consumption of the hydraulic oil flowing from the overflow valve back to the oil tank, thus saving a lot of electric energy. According to the different injection molding products, the power consumption of the motor is monitored in real time, and the power saving rate reaches 20-70%.

2. Avoid personal safety accidents
After the injection molding machine is equipped with a frequency converter, when the operator takes parts from the mold, cleans and repairs the mold, the speed analog value of the plastic machine computer has no output, the motor is at a standstill, and the hydraulic system has no pressure, which avoids mechanical malfunctions. Completely put an end to the occurrence of personal safety accidents of injection molding machines.

3. Soft start
Under the condition of power frequency, the motor adopts star-delta step-down delay start. At this time, the current is 4 to 7 times the rated current of the motor. If multiple high-power motors start at the same time, it will cause a great impact on the power grid. After adopting frequency conversion speed regulation, the motor can be soft-started only at the rated current, and the current is smooth without impact, which reduces the impact of the starting current on the motor and the grid, and prolongs the service life of the motor.

4. Reduce reactive power
Reactive power not only increases line loss and heat generation of equipment, but also reduces the active power of the grid due to the reduction of power factor. After using the frequency conversion speed regulation energy-saving control device, due to the effect of the filter capacitor in the frequency converter, the power factor is close to 1, which increases the active power of the grid, thereby saving the energy consumed by reactive power.

For the plastic product industry, power consumption is the main part of its production cost, and the injection molding machine is one of the main energy-consuming equipment in the plastic product factory. Therefore, reducing the energy consumption of the injection molding machine has become the key for the injection molding industry to reduce costs and improve product competitiveness Effective Ways.

At present, most of the injection molding machines are hydraulic transmission injection molding machines, and the power in the hydraulic transmission system is provided by the motor driving the oil pump. During the injection molding cycle, the flow rate and pressure required by the injection molding machine in different processes are different, and flow and pressure required by different processes must be adjusted by means of flow valves and pressure valves. The load of the hydraulic system varies greatly. Since the fixed displacement pump cannot adjust the output power, the excess energy can only be consumed in the baffle plate, oil leakage, and oil temperature rise. This not only aggravates the wear of various valves, but also causes excessive oil temperature, excessive motor noise, and shortened mechanical life. And usually in the design, the designed capacity of the user’s oil pump motor is much higher than the actual need, and there is a phenomenon of “big horses and small carts”, resulting in a large waste of electric energy. Therefore, it is of great significance to promote the application of AC frequency conversion speed control devices in injection molding machines to reduce energy waste.

Application of VFD in Injection

Advantages of using frequency converters in injection molding machines:

1. Energy saving
The three sets of asynchronous AC motors usually used in injection molding machines cannot change the speed, and the quantitative vane pump driven by them cannot change the flow rate of the output hydraulic oil. When the injection molding machine is operating at a low speed, the excess flow flows back to the oil tank through the overflow valve, resulting in a large loss of energy. The frequency converter can adjust the speed of the motor according to the instructions of the control system, so that the flow rate of the hydraulic oil output by the vane pump can be changed according to the action speed of the injection molding machine, which reduces the energy consumption of the hydraulic oil flowing from the overflow valve back to the oil tank, thus saving a lot of electric energy. According to the different injection molding products, the power consumption of the motor is monitored in real time, and the power saving rate reaches 20-70%.

2. Avoid personal safety accidents
After the injection molding machine is equipped with a frequency converter, when the operator takes parts from the mold, cleans and repairs the mold, the speed analog value of the plastic machine computer has no output, the motor is at a standstill, and the hydraulic system has no pressure, which avoids mechanical malfunctions. Completely put an end to the occurrence of personal safety accidents of injection molding machines.

3. Soft start
Under the condition of power frequency, the motor adopts star-delta step-down delay start. At this time, the current is 4 to 7 times the rated current of the motor. If multiple high-power motors start at the same time, it will cause a great impact on the power grid. After adopting frequency conversion speed regulation, the motor can be soft-started only at the rated current, and the current is smooth without impact, which reduces the impact of the starting current on the motor and the grid, and prolongs the service life of the motor.

4. Reduce reactive power
Reactive power not only increases line loss and heat generation of equipment, but also reduces the active power of the grid due to the reduction of power factor. After using the frequency conversion speed regulation energy-saving control device, due to the effect of the filter capacitor in the frequency converter, the power factor is close to 1, which increases the active power of the grid, thereby saving the energy consumed by reactive power.

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