How to control injection pressure of PET injection molding machine?

The control of injection pressure is one of the key operations of a PET injection molding machine, which directly affects the quality and production efficiency of molded products. By properly adjusting the injection pressure, you can ensure that the molten PET material fully fills the mold cavity and avoids the mixing of air or bubbles, thereby producing high-quality plastic products that meet the design requirements. The following is a detailed analysis of the injection pressure control of PET injection molding machines:

1. Injection system design:

The injection system is one of the core components of the PET injection molding machine, including screw, barrel, nozzle, etc. Reasonable design of the injection system is crucial to achieve effective control of the injection pressure. Usually, the design of the injection system needs to take into account parameters such as screw diameter, pitch, screw speed, etc. to meet the requirements of different molded products.

2. Setting of injection pressure:

PET injection molding machines are usually equipped with an injection pressure control device, and the operator can set the injection pressure through the control panel or computer interface. In the setting stage, the specific molded product requirements and the melting characteristics of the PET material need to be taken into consideration to determine a suitable injection pressure value.

3. Closed-loop control system:

Advanced PET injection molding machines usually use closed-loop control systems that can monitor the injection pressure in real time and make feedback adjustments. Through the real-time data obtained by the sensor, the control system can automatically adjust the working status of the hydraulic system or motor to keep the injection pressure within the set value range.

4. Adjust the injection speed:

Injection pressure is closely related to injection speed. By adjusting the injection speed, the speed at which the molten PET material enters the mold cavity can be affected, thereby adjusting the injection pressure. In general, a higher injection speed may require a higher injection pressure.

5. Monitoring and optimization of the melting process:

Injection molding machines are usually equipped with monitoring systems that can monitor various parameters during the melting process in real time, including injection pressure, temperature, screw position, etc. Through the analysis of these data, the melting process can be optimized to improve the accuracy and efficiency of injection molding.

6. Mold design and flow channel optimization:

Properly designed molds and optimized flow channel structures can also affect the control of injection pressure. The size and layout of the runner needs to be able to ensure that the molten PET material maintains a uniform flow when entering the mold cavity and reduces the fluctuation of the injection pressure.

7. Application of load sensor:

In the injection part, the application of load sensors can monitor the load of the injection mechanism in real time. Feedback from these sensors can be used to adjust the hydraulic system to maintain stable injection pressure.