Open and close mold control during plastic injection molding

Oct 24, 2024Leave a message

Mold opening control:

When the molten plastic is injected into the mold cavity and the cooling is completed, the product is removed with the opening action. The mold opening process is also divided into three stages. In the first stage, the mold is opened slowly to prevent the parts from tearing in the mold cavity.

The second stage is rapid mold opening to shorten the mold opening time. The third stage is slow mold opening to reduce the impact and vibration caused by mold opening inertia.

Closing control:

The mold closing is a huge mechanical thrust to close the mold to resist the high pressure injection of molten plastic and fill the mold during the injection process and the huge opening force of the mold.

Close the safety door, each stroke switch gives a signal, and the mold closing action starts immediately. First of all, the moving template starts at a slow speed, and after a short distance forward, the control rod press block that originally held the slow switch is detached, and the movable plate turns to push forward quickly. When advancing near the end of the closing, the other end of the control rod presses the slow switch, and the movable plate turns to slow speed and low pressure forward.

In the process of low pressure closing, if there is no obstacle between the molds, it can be smoothly closed to press the high pressure switch, and the high pressure is to straighten the machine hinge to complete the closing action. This distance is very short, generally only 0.3~1.0mm, just turn the high pressure immediately touch the closing stop limit switch, then the action stops, the closing process ends.

The mold closing structure of injection molding machine has full hydraulic type and mechanical connecting rod type. No matter what kind of structure form, the final connecting rod is completely straightened to implement the clamping force. The straightening process of the connecting rod is the process of stretching the movable plate and the tail plate, and also the process of stretching the four tie rods.

The size of the clamping force can be known from the maximum value of the oil pressure gauge rising at the moment of the clamping die, the maximum value of the oil pressure gauge is high when the clamping force is large, and the other is low. The smaller injection molding machine does not have a clamping oil pressure gauge, and it is necessary to judge whether the mold is really tight according to the straightening of the connecting rod.

If the connecting rod of an injection molding machine is easily straightened when the mold is closed, or the "difference" is not straightened, or a pair of connecting rods is not completely straightened, the mold will appear when the injection molding, and the parts will appear flash or other problems.

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