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Plastic mold design knowledge

 

一, Design Basis

Dimensional accuracy associated with the correctness of size.
    According to plastic products specific to the product and functions to determine its quality and the specific size of the outside part of which:
    Appearance quality requirements for high dimensional accuracy, less demanding of plastic products such as toys;
    Functional plastic products, size, demanding;
    Appearance and size are very strict plastic products such as cameras.
    Stripping Slope is reasonable.
    Stripping slope is directly related to the stripping and quality of plastic products, that is related to the injection process, the injection can be smoothly carried out:
    Stripping Slope are adequate;
    Slope with plastic products in forming sub-module or sub-module Face adaptation; whether it will affect the appearance and wall thickness dimensions of accuracy;
    Will this affect some parts of the intensity of plastic products.

二, Design Process

Map of plastic products and entities (real sample) analysis and digestion:
    A, products of the geometric shapes;
    B, dimensions, tolerances and design benchmarks;
    C, technical requirements;
    D, plastic name, grade E, the surface of demand

Cavity volume and cavity arrangement:
    A, product weight and injection machine injection quantity;
    B, products of the projected area of the clamping force and injection machines;
    C, mold size and shape mold injection machine to install an effective area (or within the injection machine rod spacing)
    D, product accuracy, color;
    E, whether the side axle core products and its processing method;
    F, products of production batch;
    G, cost-effective (each mode of production value)

Cavity volume has been determined, they carried out the arrangement of the cavity, that is, the location of the cavity layout involves the arrangement of the cavity mold size, gating system design, gating system balance, core pulling (slider) institutional design, inserts and the Core design, heat exchange system design, and above these issues and sub-type surface and the choice of gate location related, specifically in the design process, we must make the necessary adjustments to achieve more perfect design.

三, Sub-Surface Determination

Does not affect the appearance;
    Helping to ensure product precision, die processing, especially in the processing cavity;
    Is conducive to pouring system, exhaust system, cooling system design;
    Is conducive to open-mode (sub-die, mold release) to ensure that, when in open mode, so that products stay in the side of the dynamic model;
    To facilitate the arrangement of metal embedded blocks.

四, Design of Gating System

Gating system design, including the choice of the mainstream Road, shunt sectional shape and size determine the choice of gate position, gate gate section of the form and size to determine when the use of point gate, in order to ensure that the shunt is also shedding should be noted that de-gate device design, de-pouring device body gate nine chapters.
In the design of gating system, the first is to select the location of the gate. Gate location selection is directly related to product quality and injection molding process carried out smoothly, the choice of gate location should follow the following principles:
    ① Gate location should be advised to select the sub-type surface in order to facilitate processing and use of mold clean-up when the gate;
    ② gate location in various parts of the distance from the cavity should be consistent, and to a process for the shortest;
    ③ gate location should ensure that when the plastic into the mold cavity, the cavity in the spacious, thick-walled parts, in order to facilitate the smooth flow of plastic;
    ④ gate location should be in the thickest section in the plastic parts Office;
    ⑤ to avoid the plastic when straight into the cavity in the shed-type parietal, cores or inserts, so that plastic can flow into the cavity of each part as soon as possible and to avoid deformation of cores or inserts;
    ⑥ try to avoid products produced weld marks, or to weld marks arise in unimportant parts of products;
    ⑦ gate location and the plastic flow direction, should make plastics into the cavity, the cavity along a direction parallel to flow evenly and facilitate the discharge of gas cavity;
    ⑧ gate should be set at the products on the most vulnerable to remove the site, as far as possible without affecting the appearance of the product.

5, exhaust system design

Exhaust system to ensure product quality plays a vital role in shaping.

A, the use of exhaust ducts, exhaust ducts, usually located in the cavity is finally filled with the site, exhaust ducts, the depth varies due to plastic, plastic does not produce basically fly by the side of the maximum allowable gap to identify, such as the ABS 0.04 to 0.02 marl 0.02mm steel under the following game.

B, the use of Core Inserts putter, etc. with the plug gap or special exhaust venting;

C, sometimes in order to prevent the products in the top out of the vacuum caused by deformation, must be set up gas sales;

D, sometimes in order to prevent the products and mold a vacuum adsorption, adsorption of components designed to prevent a vacuum.

6, cooling system design

The cooling system design is a relatively tedious tasks, namely, to consider the cooling effect and cooling uniformity, but also consider the cooling system to mold the whole structure.
    The arrangement of the cooling system and cooling system, the specific form;
    Cooling system to determine the specific location and size;
    Key positions, such as moving the cooling mode, or inserts;
    And lateral side of the slider-type core cooling;
    The design of the cooling element and cooling the selection of standard components;
    Seal structure design.
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