1. Acceptance of a task bookThe task document for molded plastic parts is usually presented by the designer.1. the formal drawing made by the trial shall be signed, and the grades and transparency of the plastic shall be specified.2. specification or technical requirements for plastic parts.3. production production.4. samples of plastic parts.Usually, the mold design task book is put forward by the plastic part technician according to the task book of the molded plastic parts. The mould designer will design the mould based on the task book of molding plastic parts and the design task book of the mould.Two. Collecting, analyzing and digesting the original dataCollect and collate relevant information about parts design, molding process, molding equipment, machining and special processing, so as to make use of mold design.1. digest the plastic parts drawing, understand the use of the parts, analyze the technological requirements of the plastic parts, dimensional accuracy and other technical requirements. For example, what are the requirements of plastic parts in appearance shape, color transparency, and performance, whether the geometric structure of the plastic parts, the slope, the inlay and so on are reasonable, the allowable degree of the forming defects such as weld marks and shrinkage holes, and the addition of coating, electroplating, bonding, drilling and so on. Select the size of the highest dimensional precision of the plastic parts, to see if the tolerance of the molding is lower than the tolerance of the plastic parts, and whether the required plastic parts can be formed. Besides, it is necessary to understand the plasticizing and molding process parameters of plastics.2. the data of digestion process, analysis of the molding method, equipment model, material specification, mould structure type and so on.The molding materials should meet the strength requirements of plastic parts with good fluidity, homogeneity, isotropy and thermal stability. According to the use of plastic parts, the molding materials should meet the requirements of dyeing, plating metal conditions, decorative properties, necessary elastic and plastic, transparent or opposite reflection, adhesively, or weldability.3. determine the molding methodThe direct pressure method, the casting pressure method or the injection method are used.4. Select the molding equipmentAccording to the type of molding equipment, mold must be familiar with the performance, specifications and characteristics of various molding equipment. For example, for injection machine, the following contents should be understood in specifications: injection capacity, mode locking pressure, injection pressure, mold installation size, ejection device and size, nozzle hole diameter and nozzle sphere radius, gate sleeve size, maximum thickness and minimum thickness of mold, template stroke, etc. Parameters.It is necessary to preliminarily estimate the size of the die and determine whether the mold can be installed and used on the selected injection machine.5. concrete structure scheme(1) determine the mold typeSuch as pressing die (open, semi closed, closed), casting die, injection mold, etc.(2) determine the main structure of the mold typeThe ideal mold structure is chosen to determine the necessary molding equipment, the ideal number of cavity, and in absolute and reliable conditions, the work of the mould itself can meet the requirements of the technology and production economy of the plastic parts. The technical requirements for plastic parts are to ensure the geometric shape, surface finish and dimensional accuracy of plastic parts. The requirement of production economy is to make the cost of plastic parts low, the production efficiency is high, the mold can work continuously, the service life is long, and the labor force is saved.Three, there are many factors that affect the die structure and individual system.Type 1. cavity layout. According to the geometric characteristics of the plastic parts, size accuracy requirements, batch size, mold manufacturing difficulties, mold cost and so on, determine the number and arrangement of the cavity.For injection mould, the precision of the plastic parts is 3 and 3a, the weight is 5 grams, the hardened casting system is adopted, the number of the cavity is 4-6; the plastic parts are the general precision (4-5 grade), the molding material is the local crystallizing material, the number of the cavity is 16-20, the weight of the plastic part is 12-16 grams, the number of the cavity is 8-12, and the weight is 50-10. 0 grams of plastic parts, the number of cavities of 4-8. For amorphous plastic parts, the number of recommended cavities is 24-48, 16-32 and 6-10. When we continue to increase the weight of plastic parts, we seldom use multi cavity mold. For plastic parts with 7-9 grade accuracy, the maximum number of cavity is increased to 50% compared with the 4-5 grade precision plastic.2. determine the parting surface. The location of the parting surface is conducive to mold processing, exhaust, stripping and molding operations, surface quality of plastic parts, etc.3. determine the gating system (main runner, runner and gate shape, location, size) and exhaust system (exhaust method, exhaust slot location, size).4. select the ejection mode (ejector pin, pipe jacking, push plate and combined ejection) to decide the side concave treatment method and core pulling method.5. determines the cooling and heating mode and the shape and location of the heating cooling trench, and the installation part of the heating element.