The selection of the parting surface is the first step in the design of the mold. It is affected by many factors such as the shape, appearance, wall thickness, dimensional accuracy, and number of cavities. It is easy to determine the parting surface for general products. But for some parts that have side cores, or when it comes to pillows, bumps, and insertions, it is not easy.

In general, parting surface will follow the following principles:

  1. For easy demolding

The parting surface, that is, the product can smoothly come out the surface of the mold. Therefore, the position of the parting surface should be selected in the part with the largest product section size. This is the most basic principle.

  • Position

When determining the product position in the mold, the location of the parting surface should try to prevent the product from forming side holes or side buckles, and avoid complicated mold structures.

  • Shape

Normally the parting surface is perpendicular to the direction of injection mold opening movement. Only under special circumstance, the parting surface is in other shapes. The shape of the parting surface is based on the principle of easy processing and demolding. For example, some curved products are classified according to the curvature of the bending.

  • Ensure product appearance and quality

Do not put the parting surface on the smooth outer surface of the product. In general, the appearance of the surface is not allowed to have lines and other lines that affect the appearance of aesthetics; some products with concentricity requirements, all parts with the same degree of concentricity must be placed on the same side, so as to ensure their concentricity.

  • Consider lateral mold opening distance

In general, the distance from the lateral mechanical mold opening is relatively small. Therefore, when selecting the parting surface, the direction in which the core distance is long should be selected in the direction in which the front and rear molds are opened and closed, and the short direction is used as the side type.

  • Consider clamping force

The lateral clamping force of the mold is relatively small. Therefore, for a large product with a large projection area, the direction of the large projection area should be placed in the direction of the front and rear mold opening and closing, and the side projection area should be smaller.

  • Good for air venting

When the parting surface is used as the main exhaust, the parting surface should be designed at the end of the plastic flow to facilitate the exhaust.

  • Mold parts are easy to process

When selecting a parting surface, the mold should be divided into parts that are easy to machine, reducing the difficulty of machining.

  • R parting surface

For many products, there is a full circle of R angles at the parting surface. At this time, the classification is based on the best classification of R, and the sharp side cannot be seen.