Ten steps in plastic mold design

1. Accept the task book

1. A formal part drawing that has been reviewed and signed, and the brand and transparency of the plastic used are indicated.

2. Production output.

Usually, the mold design task book is proposed by the plastic part technician based on the task book of the molded plastic part, and the mold designer designs the mold based on the task book of the molded plastic part and the mold design task book.

1. Digest the plastic part drawing, understand the purpose of the part, and analyze the processability, dimensional accuracy and other technical requirements of the plastic part.

2. Digest the process data and analyze whether the molding method, equipment model, material specification, mold structure type and other requirements proposed in the process task book are appropriate and can be implemented.

3. Determine the molding method - use direct pressing, casting or injection molding.

4. Make molds according to the type of molding equipment, so you must be familiar with the performance, specifications and characteristics of various molding equipment. For example, for injection molding machines, the following specifications should be understood: injection capacity, clamping pressure, injection pressure, mold installation size, ejector device and size, nozzle hole diameter and nozzle spherical radius, gate sleeve positioning ring size, maximum mold thickness and minimum mold thickness, template stroke, etc., see the relevant parameters for details.
5. Specific structural scheme
Such as compression molds (open, semi-closed, closed), die casting molds, injection molds, etc.
Choosing an ideal mold structure is to determine the necessary molding equipment, the ideal number of cavities, and to enable the mold itself to meet the process technology and production economic requirements of the plastic part under reliable conditions. The process technology requirements for plastic parts are to ensure the geometric shape, surface finish and dimensional accuracy of plastic parts. The production economic requirements are to make the cost of plastic parts low, the production efficiency high, the mold can work continuously, the service life is long, and labor is saved.
1. Cavity layout. Determine the number of cavities and their arrangement according to the geometric structure characteristics of the plastic part, dimensional accuracy requirements, batch size, mold manufacturing difficulty, mold cost, etc.
2. Determine the pouring system (shape, position, size of the main runner, branch runner and gate) and the exhaust system (exhaust method, exhaust groove position, size).

3. Determine the cooling and heating methods and the shape, position of the heating and cooling grooves, and the installation position of the heating elements.

4. Determine the structural form of the main molding parts and structural parts.

If the above problems are solved, the structural form of the mold will naturally be solved. At this time, you should start to draw the mold structure sketch to prepare for the formal drawing.
It is required to draw according to the drawing standards, but it is also required to combine the factory standards and unspecified factory customary drawing methods.
It is better to mark the part number, name, material, material shrinkage, drawing scale, etc. under the process diagram. Usually, the process diagram is drawn on the mold assembly drawing.
When drawing the assembly drawing, try to use a 1:1 ratio, start with the cavity, and draw the main view and other views at the same time.
2. The structural form of the pouring system and the exhaust system. 4. The shape structure and the position of all connectors, positioning and guide parts.
6. Auxiliary tools (tools for removing and unloading parts, correction tools, etc.).
8. Marking technical requirements and instructions for use.
1. Performance requirements for certain systems of the mold. For example, assembly requirements for the ejection system and the slider core pulling structure.
3. Mold use, assembly and disassembly methods.
5. Requirements for mold trial and inspection.
The order of drawing parts from the mold assembly drawing should be: first inside, then outside, first complex, then simple, first forming parts, then structural parts.
2. The dimensioning requirements are unified, centralized, orderly and complete. The order of dimensioning is: first mark the main part size and mold draft, then mark the matching size, and then mark all the dimensions. Mark the matching size first on the non-main part drawing, and then mark all the dimensions.
4. Other contents, such as part name, mold drawing number, material brand, heat treatment and hardness requirements, surface treatment, graphic ratio, free size processing accuracy, technical specifications, etc. must be filled in correctly.
(I) The contents of self-checking are:
Whether the material, hardness, dimensional accuracy, structure, etc. of the mold and mold parts meet the requirements of the plastic part drawings.
Whether the flow of plastic material, shrinkage holes, weld marks, cracks, demoulding slope, etc. affect the requirements of the use performance, dimensional accuracy, surface quality, etc. of plastic parts. Whether the pattern design is insufficient, whether the processing is simple, and whether the shrinkage rate of the molding material is correctly selected.
Whether the injection volume, injection pressure, and clamping force are sufficient, whether there are any problems with the installation of the mold, the core of the plastic part, and demolding, and whether the nozzle of the injection machine is in correct contact with the nozzle sleeve.
1). Whether the position of the parting surface and the finishing accuracy meet the requirements, whether there will be overflow, and whether the plastic parts can be guaranteed to remain on the side of the mold with the ejector device after the mold is opened.
3). Mold temperature adjustment. The power and quantity of the heater; whether the location, size and quantity of the cooling medium flow line are appropriate.
5). Whether the location and size of the pouring and exhaust system are appropriate.