Most of the injection molding machines in the market are using hydraulically driver. The power in the injection molding system is supplied by the machine’s driving the oil pump. The machine needs different flow and pressure in different working procedure and the loading changes a lot. Besides, the output power of the constant pump is irregulative. Hence the extra energy is consumed in the damper, divulging of the oil circuit, the heating of the oil, which aggravates the wearing among the valves, as well as the over-heating oil circuit, over-noisy of the machine. Besides, the energy wasting is very common in this field. So it will be very significant in energy-saving to popularize the frequency conversion technology.
The usually procedure of injection mould is below: locking mode—-keeping pressure by injection—-melting the glue and fuelling it—-cooling pitching—-opening mould and thimble. Every step has the wonderful coordination of time, pressure, speed and position, which means every displacement has the corresponding pressure and speed and the pressure and speed are changeable in different position and time. Meanwhile, each time when finishing one step, the terminal signals will be sent to the program controller and the controller will send out the order for the next step.
The traditional injection molding machine uses constant pump supplying oil. Hence different steps need different speed and pressure during the procedure. The motor keeps one speed during the whole course, so the fuel supply quantity is fixed. The operation is intermittent, so it can’t be always full-loaded. Thus there is a lot of energy wasted in the traditional fixed oil-supplying quantity system. It is measured at least 50% is wasted. Energy-saving frequency inverter drive detects the proportional pressure and proportional flow signals from the injection molding control system and adjust the motor speed needed by each step timely (flow regulation), which makes the flow and pressure of pump just fit for the system’s need. While in off-working status (mainly cooled status), stopping the motor will save more energy. Concluded speaking, the regulating-frequency technology can bring great energy-saving effect to the machine.