How to control the injection speed and pressure of the injection molding machine?

The injection speed of an injection molding machine refers to the injection rate of the plastic material before it enters the mold. It directly affects the filling time and filling pressure distribution of the plastic in the mold cavity. The control of the injection speed needs to be adjusted according to the characteristics of the specific product and plastic material. The methods for controlling the injection speed mainly include the following:

1. Conventional control valve control: The injection speed is adjusted by controlling the valve that controls the flow of oil. This method is usually used for simple injection molding machines and has a relatively basic speed adjustment function.

2. Servo motor control: The injection system is driven by a servo motor, and the injection speed is controlled by adjusting the motor speed. This method has higher accuracy and response speed and is suitable for high-demand injection molding processes.

3. Proportional valve control: Use a proportional valve to control the flow of the hydraulic system to achieve precise injection speed adjustment. The proportional valve controls the flow through an electromagnetic signal, so that the injection speed can be accurately adjusted and controlled.

The injection pressure of an injection molding machine refers to the pressure applied to the mold during the plastic injection process. It affects the filling, compaction and cooling process of the plastic material, and is directly related to the density, quality and dimensional accuracy of the product. The methods of controlling injection pressure mainly include the following:

1. Oil pressure control: The injection pressure is adjusted by controlling the oil pressure of the hydraulic system. By adjusting the oil supply and flow control valve, the injection pressure of the injection molding machine can be accurately controlled.

2. Pressure sensor feedback control: The actual pressure during the injection molding process is measured using a pressure sensor and fed back to the control system. The control system adjusts the output of the hydraulic system according to the difference between the set value and the actual value to achieve accurate control of the injection pressure.

3. Closed-loop control system: A closed-loop control system is used to monitor and adjust the injection pressure. The system automatically adjusts the output of the hydraulic system to maintain a stable injection pressure by continuously detecting the injection pressure and comparing it with the set value.