The quality ofInjection mold is depent on the design

- Feb 12, 2019-

I). Design basis

    Accuracy is related to accuracy

   According to the specific requirements and functions of the whole product of plastic products to determine its external quality and specific size belongs to which kind: the appearance of high quality requirements, dimensional accuracy requirements of plastic products, such as toys;Functional plastic products, strict size requirements;A plastic product, such as a camera, that is rigid in appearance and size.

· 2.Draft is reasonable.

    Demoulding slope is directly related to the plastic products demoulding and quality, that is, related to the injection process, whether the injection can be carried out smoothly: demoulding slope is enough;Slope and plastic products in the molding of the parting or parting surface;Whether it will affect the accuracy of appearance and wall thickness size;

·   It would affect the intensity of a portion of the plastic products.


2), design the program

Analysis and digestion of plastic product drawing and solid (solid sample) :

    Product geometry;

 ·  Dimensions, tolerances, and design basis;

   Technical requirements;

·  Plastic name and brand

   Surface requirement

   Cavity number and cavity arrangement:

   Product weight and injection machine injection;

   Product projective and injection of locking force;

·  Mold dimension and injection machine mould effective area, installation (or injection machine bar spacing)

·  Products, color accuracy;

Products have no side shaft and its treatment method;

Production batch of products;

Economic efficiency (production value per module)

Cavity number was determined, and then to the arrangement of cavity, the cavity position arrangement, cavity arrangement involves the mould size, the design of gating system, the balance of gating system, the design of the core-pulling slider) institutions, insert, and the design of the core, the design of the heat exchange system, these problems and parting surface and the selection of gate location, so in the process of the specific design, to make the necessary adjustments, in order to achieve more perfect design.


3). Determination of parting surface

    Ineffect appearance

·   To ensure accuracy of product, mold processing, especially for mold processing;

·   It is advantageous to the gating system, exhaust system and cooling system design;

·   To open mold (mold, mold release) to ensure that in the mould, make the products in dynamic model on one side;

    Facilitate the placement of metal Mosaic.


4). Design of casting system

   The design of the pouring system includes the selection of the main flow channel, the determination of the shape and size of the shunt section, the location of the sprue, the form of the sprue and the determination of the size of the sprue section.

   When designing a gating system, the location of the gate is chosen first.

  The selection of gate location is directly related to the product molding quality and the smooth process of injection. The selection of gate location should follow the following principles:

·  Gate location should choose as far as possible in the parting surface, so that the mould processing and gate when using clean;

  ·The distance of each place gate location from the cavity should be consistent as far as possible, and make the process as the shortest;

·   The location of the gate shall ensure that the plastic flow into the cavity, the cavity in the spacious, thick wall parts, so that the plastic flow smoothly;

    The placement of pouring place should be set up;

·   Avoid plastic in the flow in the straight at cavity wall cavity, core, or insert each position can make the plastic into the cavity as soon as possible, and to avoid deformation of the core or insert;

·   Try to avoid making products produce weld mark, or make the weld mark in the products is not important part;

·   Gate location and its plastic flow direction, should make when plastic flow into the cavity, can evenly into the cavity of the parallel direction, and is conducive to the discharge of gas inside the cavity;

·   Gate should be set at the site of the products on the most easily remove, at the same time does not affect the product appearance as much as possible.

5). Exhaust system design

   The exhaust system plays an important role in ensuring the forming quality of products.

The exhaust slot is generally located at the part where the cavity is filled at the end. The depth of the exhaust slot varies with different plastics, and is basically determined by the maximum clearance allowed by plastics without flanging, for example, ABS0.04, below 0.02mm of marl and below 0.02 of steel.

   Use the matching clearance of the core insert push rod or special exhaust plug to exhaust;Sometimes in order to prevent the products in the ejection caused by vacuum deformation, it is necessary to set the gas pin;Sometimes anti-vacuum adsorption components are designed to prevent the vacuum adsorption of products and modules.

6). Cooling system design

    The design of cooling system is a complicated work, which needs to consider the cooling effect and the uniformity of cooling, as well as the influence of cooling system on the overall structure of the mold