Many novice mold designers don’t know the processing sequence of mold parts!

Therefore, it is easy to make common sense mistakes during design, resulting in increased processing costs. Today I will share with you an article on the processing sequence process of mold parts! I hope to be helpful!

Cutting materials: front mold material, rear mold material, insert material, row position material, inclined roof material;

Open frame: front mold frame, rear mold frame;

Roughening: The front mold cavity is thickened, the rear mold cavity is thickened, and the parting line is thickened;

Copper male: front mold copper male, rear mold copper male, parting line clear angle copper male;

Wire cutting: insert parting line, copper pin, inclined top pillow position;

Computer gong: fine gong parting line, fine gong rear mold core;

EDM: Front mold is thick, copper male, male mold line clear corner, rear mold bone position, pillow position;

Drill holes, pinholes, thimbles;

Row position, row position pressure extreme;

Sloping roof

Repeated thimbles and matching thimbles;

Others: ① Nozzle, code mold pit, garbage nail (limiting nail); ② Flying mold; ③ Nozzle, support head, spring, water transport;

Mold saving, polishing, front mold and rear mold bone position;

Thin water structure, pull rod screw hook, spring

Quenching and surface nitriding;

Mold repair and lettering.

Mold design knowledge

1. Design basis

Dimensional accuracy and correctness of its associated dimensions.

According to the specific requirements and functions of the entire plastic product, determine which type its outer quality and specific size belong to:

Plastic products with higher appearance quality requirements and lower dimensional accuracy requirements, such as toys;

Functional plastic products have strict size requirements;

Plastic products with strict appearance and size requirements, such as cameras.

Is the draft angle reasonable?

The demoulding slope is directly related to the demoulding and quality of plastic products, that is, whether the injection can proceed smoothly during the injection process:

The draft angle is sufficient;

The slope must be compatible with the molding or parting surface of the plastic product; whether it will affect the appearance and wall thickness accuracy;

Will it affect the strength of certain parts of plastic products?

2. Design program

Analysis and digestion of plastic product drawings and entities (real samples):

a. The geometric shape of the product; b. Dimensions, tolerances and design standards;

c. Technical requirements; d. Plastic name and brand e. Surface requirements

Number of cavities and cavity arrangement:

a. The weight of the product and the injection volume of the injection machine; b. The projected area of the product and the clamping force of the injection machine;

c. The overall dimensions of the mold and the effective area of the mold installed on the injection machine (or the inner spacing of the injection machine tie rod)

d. Product accuracy and color; e. Whether the product has side shaft core and its processing method;

f. Production batch of products; g. Economic benefits (production value of each mold)

After the number of cavities is determined, the arrangement of the cavities is carried out, that is, the arrangement of the cavity positions. The arrangement of the cavities involves the size of the mold, the design of the gating system, the balance of the gating system, the design of the core-pulling (slider) mechanism, and the inserts. As well as the design of the core and the design of the heat exchange system, these issues are related to the selection of the parting surface and gate location. Therefore, necessary adjustments must be made during the specific design process to achieve a more perfect design.

3. Determination of parting surface

Does not affect appearance;

It is helpful to ensure product accuracy and mold processing, especially cavity processing;

Conducive to the design of pouring systems, exhaust systems, and cooling systems;

It is conducive to mold opening (mold splitting, demoulding) and ensures that the product remains on the side of the movable mold when the mold is opened;

Facilitates the arrangement of metal inserts.

4. Design of pouring system

The design of the gating system includes the selection of the main channel, the determination of the cross-sectional shape and size of the runner, the selection of the location of the gate, the determination of the gate form and the gate cross-section size. When using point gates, in order to ensure that the runner falls off, Attention should be paid to the design of the de-gating device and the nine-chapter gate mechanism of the de-gating device.

When designing a gating system, the first step is to select the location of the gate. The selection of gate location is directly related to the quality of product molding and the smooth progress of the injection process. The selection of gate location should follow the following principles:

① The gate position should be chosen on the parting surface as much as possible to facilitate the cleaning of the gate during mold processing and use;

②The distance between the gate position and each part of the cavity should be as consistent as possible, and the tooling process should be kept as short as possible;

③The position of the gate should ensure that when the plastic flows into the cavity, it should be in a wide and thick-walled part of the cavity to facilitate the smooth flow of plastic;

④The gate should be located at the thickest section of the plastic part;

⑤ Prevent the plastic from flowing directly into the cavity wall, core or insert when flowing down the cavity, so that the plastic can flow into all parts of the cavity as quickly as possible and avoid deformation of the core or insert;

⑥ Try to avoid welding marks on the product, or make welding marks occur on unimportant parts of the product;

⑦The position of the gate and its plastic inflow direction should ensure that when the plastic flows into the cavity, it can flow evenly along the direction parallel to the cavity and facilitate the discharge of gas in the cavity;

⑧The gate should be set in the part of the product that is easiest to clean, while minimizing any impact on the appearance of the product.

5. Design of exhaust system

The exhaust system plays a vital role in ensuring the quality of product molding.

a. Use the exhaust slot. The exhaust slot is generally located at the last filled part of the cavity. The depth of the exhaust slot varies depending on the plastic.

Basically, it is determined by the maximum allowable gap of plastic without flash, such as abs below marl and below race steel.

b. Use the matching clearance of the core insert, push rod, etc. or the special exhaust plug to exhaust air;

c. Sometimes, in order to prevent vacuum deformation of the product during ejection, air pins must be installed;

d. Sometimes, in order to prevent vacuum adsorption of products and molds, anti-vacuum adsorption components are designed.

6. Design of cooling system

The design of the cooling system is a relatively complicated task, which requires considering the cooling effect and uniformity of cooling, as well as the impact of the cooling system on the overall structure of the mold.

The arrangement of the cooling system and the specific form of the cooling system;

Determination of the specific location and size of the cooling system;

Cooling of key parts such as movable molds or inserts;

Cooling of side slider and side core;

Design of cooling components and selection of cooling standard components;

Sealed structural design.

drawing mold drawing

1. When transferring the finished product drawing into the mold drawing, the finished product drawing must be multiplied and shrunk. (Mold size = product size Lines are deleted in the back mold, and lines that do not belong to the back mold should be deleted.

2. The finished product should follow the principle of centering in the mold, especially if it is symmetrical. If the finished product is not centered, errors are likely to occur when it is processed in the factory.

3. For all pillow position molds, the pillow position must be protected from water. If it is impossible to avoid it, a sprue iron must be added.

4. The distance between finished products is 12-20mm (under special circumstances, it can be 3mm). When entering the water for diving, there should be enough diving position. The distance between the finished product and the core is 15-50mm. The distance between the finished product and the core is related to the storage degree of the product. , general products can be selected by referring to the empirical values in the table below.