1、 Die manufacturing process acceptance assignment

The task book for forming plastic parts is usually proposed by the part designer, and its content is as follows:

(1). Approved and signed drawings of formal manufactured parts, indicating the grade and transparency of the plastic used.

(2). Instructions or technical requirements for plastic parts.

(3). Production output.

(4). Sample of plastic parts.

Usually, the mold design task book is proposed by the plastic part technician based on the task book for forming plastic parts, and the mold designer designs the mold based on the task book for forming plastic parts and the mold design task book.

2、 Collect, analyze, and digest raw materials

Collect and organize relevant information on product design, forming process, forming equipment, mechanical processing, and special processing for use in mold design.

(1). Digest plastic part drawings, understand the purpose of the parts, analyze the technical requirements of plastic parts such as processability and dimensional accuracy. For example, what are the requirements for plastic parts in terms of appearance shape, color transparency, and performance, whether the geometric structure, slope, and embedded parts of the plastic parts are reasonable, the allowable degree of forming defects such as welding marks and shrinkage holes, and whether there is any post-processing such as painting, electroplating, bonding, drilling, etc. Select the size with the highest dimensional accuracy for plastic parts for analysis, to see if the estimated forming tolerance is lower than that of plastic parts, and whether a plastic part that meets the requirements can be formed. In addition, it is necessary to understand the plasticization and molding process parameters of plastics.

(2). Digest process data, analyze whether the requirements for forming methods, equipment models, material specifications, and mold structure types proposed in the process task book are appropriate and whether they can be implemented. The forming materials should meet the strength requirements of plastic parts, have good fluidity, uniformity, isotropy, and thermal stability. According to the purpose of plastic parts, the forming material should meet the requirements of dyeing, metal plating conditions, decorative performance, necessary elasticity and plasticity, transparency or opposite reflection performance, adhesive or weldability, etc.

(3). Determine whether the molding method is direct pressing, casting pressing, or injection molding.

(4). The selection of molding equipment is based on the type of molding equipment used for the mold, so it is necessary to be familiar with the performance, specifications, and characteristics of various molding equipment. For example, for injection machines, in terms of specifications, the following should be understood: injection capacity, mold locking pressure, injection pressure, mold installation size, ejection device and size, nozzle hole diameter and nozzle spherical radius, gate sleeve positioning ring size, maximum and minimum mold thickness, template stroke, etc. Please refer to relevant parameters for details. To preliminarily estimate the overall dimensions of the mold and determine whether it can be installed and used on the selected injection machine.

(5). Specific structural plan (1) Determine the type of mold, such as pressing mold (open, semi closed, closed), casting mold, injection mold, etc. （2） The main structure for determining the type of mold is to choose the ideal mold structure by determining the necessary molding equipment, the ideal number of cavities, and under absolutely reliable conditions, the mold itself can meet the requirements of the plastic parts' process technology and production economy. The technological requirements for plastic parts are to ensure the geometric shape, surface finish, and dimensional accuracy of the plastic parts. The production economy requires low cost, high production efficiency, continuous working of molds, long service life, and labor saving of plastic parts.

3、 There are many complex factors that affect the structure and individual systems of the mold:

(1). Cavity layout. Determine the number and arrangement of cavities based on the geometric structure characteristics, dimensional accuracy requirements, batch size, difficulty in mold manufacturing, and mold cost of the plastic parts. For injection molds, the precision of plastic parts is level 3 and level 3a, with a weight of 5 grams. A hardened pouring system is used, and the number of cavities is 4-6; Plastic parts are of general accuracy (4-5 levels), the molding material is locally crystallized material, and the number of cavities can be taken as 16-20; The weight of plastic parts is 12-16 grams, and the number of cavities is 8-12; For plastic parts weighing 50-100 grams, the number of cavities is 4-8. For amorphous plastic parts, the recommended number of cavities is 24-48, 16-32, and 6-10. When increasing the weight of plastic parts, multi cavity molds are rarely used. For plastic parts with precision levels 7-9, the maximum number of cavities increases by 50% compared to the indicated plastic parts with precision levels 4-5.

(2). Determine the parting surface. The position of the parting surface should be conducive to mold processing, exhaust, demolding, and molding operations, as well as the surface quality of plastic parts.

(3). Determine the pouring system (shape, position, and size of the main runner, sub runner, and gate) and the exhaust system (method of exhaust, position and size of the exhaust groove).

(4). Choose the ejection method (top rod, top tube, push plate, combined ejection), and determine the side concave treatment method and core pulling method.

(5). Determine the cooling and heating methods, the shape and position of the heating and cooling grooves, and the installation location of the heating elements.