Injection molding machine opening and closing mechanism

Mold opening control:

After the molten plastic is injected into the mold cavity and the cooling is completed, the mold opening action is followed to remove the product. The mold opening process is also divided into three stages. The first stage is to slowly open the mold to prevent the part from tearing in the mold cavity.

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

Mold closing control:

Clamping is the process of using a huge mechanical force to tighten the mold and resist the high pressure injection and filling of molten plastic during the injection molding process, which causes the mold to experience a huge opening force.

Close the safety door, all travel switches give signals, and the mold closing action begins immediately. Firstly, the movable template is started at a slow speed. After a short distance, the control lever that originally pressed the slow switch disengages, and the movable plate rotates to quickly advance. When moving towards the end of the mold closing, the other end of the control rod presses the slow switch again, and at this time, the movable plate turns to slow speed and advances at low pressure.

During the low-pressure mold closing process, if there are no obstacles between the molds, they can be smoothly closed until the high-pressure switch is pressed. The high-pressure switch is used to straighten the machine hinge and complete the mold closing action. This distance is extremely short, usually only 0.3~1.0mm. As soon as the high-voltage switch is turned on, it immediately touches the limit switch for closing the mold. At this point, the action stops and the closing process ends.

The clamping structures of injection molding machines include fully hydraulic and mechanical linkage types. Regardless of the structural form, the clamping force is ultimately implemented by the fully extended connecting rod. The straightening process of the connecting rod is the process of spreading the movable plate and tail plate, and also the process of stretching the four connecting rods under force.

The magnitude of the clamping force can be determined by the highest value raised by the oil pressure gauge at the moment of tightening the mold. If the clamping force is large, the highest value of the oil pressure gauge will be high, and if not, it will be low. Smaller injection molding machines do not come with a clamping oil pressure gauge, so it is necessary to determine whether the mold is truly tight based on the straightness of the connecting rod.