What are the characteristics of the hydraulic system of a precision injection molding machine?

①The oil circuit system needs to use a proportional pressure valve, proportional flow valve, or closed-loop variable pump system.

The hydraulic system of the injection molding machine needs to use a proportional pressure valve and proportional flow valve to realize different working pressure and flow rate of the system. Whether it is a quantitative pump hydraulic system or a variable pump hydraulic system, proportional valves exist to control the working pressure and working flow rate of the oil pump output and to achieve proportional linear adjustment.

② In the direct-pressure mold-closing mechanism, separate the oil circuit of the mold-closing part from the oil circuit of the injection part.

This requirement is for the direct-pressure injection molding machine because the direct-pressure injection molding machine starts to inject melt and fill the mold cavity at the moment after the mold closing starts high pressure. At the same time, there must be oil to fill the mold closing cylinder to form a high pressure for mold closing.

Otherwise, the center plate will back off due to the filling pressure and mold expansion force, which is not allowed to happen. Otherwise, the oil pump will be overloaded due to the oil filling the clamping cylinder and injection cylinder at the same time, and it will affect the injection speed and system stability.

③Because of the high speed of the precision injection molding machine, the response speed of the hydraulic system must be emphasized.

Most of the precision injection molding is done under high injection pressure and high injection speed (connector or cell phone button), the filling time is very short, generally, only a few seconds, which requires the system to have a high response performance, otherwise the response hysteresis phenomenon, which eventually leads to the system output signal and input signal requirements deviation, molding process debugging difficulties, production will also directly affect the size or weight stability of the parts.

The high responsiveness of the injection molding machine depends on the scanning time of the controller, the response time of the oil pump, and the response time of the oil valve. For hydraulic systems with servo valves, there is a considerable advantage in terms of response and repeatability.

For the variable pump injection molding machine, because the pressure and flow output of the oil pump is adjusted by the swashplate swing angle of the oil pump, it has high responsiveness and high answerability, and the repeatability of the oil pump can reach less than 0.2%.

④The hydraulic system of precision injection molding machine should fully reflect the integration engineering of machine-electric-hydraulic-apparatus.

The current injection molding machine generally adopts full computer control, the function is gradually improved, with "man-machine dialogue", fault self-diagnosis, molding state monitoring, SPC quality monitoring, and other intelligent functions. The hydraulic system of the injection molding machine is the power component of the action of the injection molding machine, the controller is the control center of the hydraulic system, and all kinds of instruments are the auxiliary monitoring part of the operation status of the machine. The injection molding machine is an intelligent body with the organic combination of machine, electricity, liquid, and instrument.