Injection molding machines are used to mold plastic products, nylon products and other automated special equipment. The working process of the injection molding machine includes pressure, heating, mold clamping, rubber injection, pressure maintenance, and mold opening.

In a working cycle, the actual pressure and the actual flow rate of the injection molding machine are varied, sometimes large and small, sometimes almost zero. When the actual flow rate is small, the oil supply of the oil pump is much greater than the actual consumption of the load.

The supply exceeds demand, and the excess hydraulic oil under high pressure overflows through the relief valve. Hydraulic oil under high pressure releases a large amount of heat energy through the relief valve. This part of the dissipated energy is actually part of the energy absorbed by the pump motor from the power grid.

The longer the small flow state is maintained, the greater the amount of power that is dissipated. Therefore, there is a serious problem of energy waste in the hydraulic system of the injection molding machine