Three Plate Mold Design Of Air Pump Plastic Cover.

This case is about the design analysis of the three plate mold. The three plate mold is also known as a double-parting surface injection mold. The difference between it and the single parting surface injection mold is that adds a stripper plate that can be moved locally in the fix Mold. Its function is to separate the parts and the runner cold slag.

This plastic part is the plastic cover of the pump. This cover has 4 holes and 2 pipes. And pipe surfaces have undercut. And there is a structure inside the longitudinal duct.As shown below.

The gate type of the three plate mold is generally a point gate. This is to better separate the product from the runner cold slag. The gate position is inside the product, so as not to affect the appearance of the product. As shown below:

Two oil cylinders are set for lateral core pulling in the horizontal pipeline. In the longitudinal pipeline, an inner slider is set under the cavity because of the undercut. Other holes should be treated with ejector sleeve. As shown below.

The mold opening sequence of the three-plate mold is very important. Additional mechanisms need to be added to ensure the mold opening sequence. Add parting locks to the movable mold plate. It is mainly used to increase the mold opening resistance between the A plate and the B plate. Make sure that the stripper plate and the fixed mold plate are separated first.

This set of three plate molds is ejected in two steps. Its combined mechanism includes return pins, stop pins, springs and other components. The following is a schematic diagram of the structure:

The first ejection is to push the B plate first to drive the slider to move.
When the mold starts to be ejected, it is due to the action of the stopper pin. The B plate is ejected together with the mechanism. The slider is installed on the B plate and moves with it. When the B plate moves to the L1 distance, the slider is separated from the product. At the same time, the limit screw starts to work, and the B plate cannot move.

The second ejection is to eject the product.
At this time, the B plate has stopped moving. The ejector plate continues to move, and the return pins forces the stop pins to retract. The return pin continues to be ejected through the B plate, and finally the product is ejected by the ejector sleeve, thus completing the whole ejecting.
The ejection process is shown in the video below.

The soul of this set of three plate mold is his secondary ejection mechanism. This is a very typical and useful combination structure. In fact, this kind of mechanism is used more. This is a very valuable reference.