Time:2019-08-29| Author:Admin
1. In accordance with the demoulding of plastic parts: In order to make the plastic parts can be taken out from the mold, the position of the parting surface should be set at the largest part of the cross section of the plastic part.
2. Number and shape of the parting surface: Usually only one parting surface perpendicular to the direction of the mold opening motion is used. Determining the fractal surface should be based on the principle of mold manufacturing and ease of demoulding.
3. Cavity selection: Try to prevent the formation of side holes and undercuts to avoid the use of more complex mold structures.
4. Ensure the surface quality: the parting surface should try not to choose the smooth outer surface of the plastic part, so as to avoid affecting the appearance quality of the plastic part; the part of the plastic part that requires the coaxiality is placed on the same side of the parting surface. In order to ensure the coaxiality of the plastic parts; to reduce the size difference requirements of the large and small ends of the plastic parts.
5. Conducive to demoulding of plastic parts: Since the demolding mechanism of the mold is usually placed on the side of the movable mold, the plastic parts are left on the side of the movable mold as much as possible after the mold is opened.
6. Consider the lateral shaft pull. Generally, the mechanical shaft type core pulling mechanism has a small lateral shaft pulling distance. Therefore, when selecting the parting surface, the direction of the core pulling or the dividing distance should be placed in the direction of the opening and closing of the moving and fixed mold, that is, The short shaft pull is used as a lateral split or core pull. And pay attention to the side core is placed on the side of the movable mold to avoid the fixed mold core.
7. Requirements for locking the mold: The lateral clamping force is small, so for large plastic parts with large projection area, the direction of the large projection area should be placed in the direction of the mold clamping of the moving and fixed molds. The direction in which the projected area is small is small as the lateral parting surface.
8. Conducive to exhaust. When the parting surface is used as the main exhaust channel, the parting surface should be designed at the flow end of the plastic to facilitate the exhaust.
9. Mold parts are easy to machine.
The thin-walled shell plastic part is tightly wrapped to enclose the core, so the core is placed on the side of the movable mold, and the concave mold is placed on the fixed mold side. After the mold is opened, the plastic part is left in the movable mold to facilitate demolding. Washer-like plastic parts, the wall is thicker and the inner hole is smaller, and the plastic part forming shrinkage has less tightening force on the core. If the cavity is set in the fixed mold, it is likely that the plastic part sticks to the fixed mold, and the mold is bound to be considered. The fixed mold double release mold, so the cavity is set in the movable mold, and the push tube or the push rod can be used for demoulding. The shape of the plastic part is relatively simple, but when there are more holes in the inside, the plastic part must remain on the core after being formed and contracted. The cavity is set in the fixed mold, the movable mold is also used to release the mold, and the mold structure is simple. The hole of the plastic part is symmetrical, so the core is also symmetrically arranged. If the plastic part is to be forced to remain in the movable mold, the cavity and most of the core can be placed in the movable mold, and the push tube is used for demoulding. The hole of the plastic part is symmetrical, so the core is also symmetrically arranged. If the plastic part is to be forced to remain in the movable mold, the cavity and most of the core can be placed in the movable mold, and the push tube is used for demoulding. The insert is provided inside the plastic part. When the outer edge is knurled, it is unreasonable to set the cavity in the fixed mold because the insert does not shrink. The cavity is set in the movable mold, and the push tube is demolded. The plastic parts have inserts. When the color gates are fed, the injection of the end of the inserts is often caused, so that the ends are overflowed. Therefore, the top feed should be used, and it is desirable to set the cavity in the movable mold to make the plastic The pieces remain in the moving mold. The coaxiality of the plastic parts is high, and all the cavities should be designed on one side of the parting surface to ensure the coaxiality of the plastic parts. When the plastic parts have side cores, the side core parts should be placed in the movable mold as much as possible to avoid the fixed core pulling. When the plastic parts have multiple sets of cores, the long end side cores should be avoided as much as possible. For thin-walled plastic parts with uniform wall thickness, one plane can not be used as the parting surface, and the tapered step parting surface can be used to ensure the uniform wall thickness of the plastic parts. The parting surface cannot be selected on the smooth outer surface of the plastic part to avoid damage to the surface quality. The parting surface cannot pass the mating surface or the thread surface with high precision on the plastic part, otherwise the dimensional accuracy of the plastic part will be affected. The projection surface is large in the direction of movement, the parting surface of the fixed mold, and the direction of the projection area is laterally divided to facilitate the locking of the mold. Generally, the parting surface should be placed at the end of the flow direction of the plastic melt as much as possible to facilitate the exhaust. Generally, the parting surface should be placed at the end of the flow direction of the plastic melt as much as possible to facilitate the exhaust. Improper selection of the parting surface will increase the difference in the size of the end of the plastic part due to the draft. The selection of the parting surface should consider the processing of the convenient cavity.