1、 Acceptance of assignment

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

　　1. Approved and signed formal manufacturing drawings, indicating the brand and transparency of plastics.

　　2. Instructions or technical requirements for plastic parts.

　　3. Production output.

　　4. Samples of plastic parts.

　　Usually, the design task book of mould plate is put forward by the plastic part technologist according to the task book of forming plastic parts, and the mould designer designs the mould according to the task book of forming plastic parts and the task book of mould design.

　　2、 Collect, analyze and digest the original data

　　Collect and sort out the information about part design, molding process, molding equipment, machining and special processing for mold design.

　　1. Digest the drawing of plastic parts, understand the use of parts, and analyze the technical requirements of plastic parts, such as processability and dimensional accuracy. For example, what are the requirements for the appearance, color transparency and performance of plastic parts, whether the geometric structure, inclination and insert of plastic parts are reasonable, the allowable degree of forming defects such as weld lines and shrinkage holes, and whether there are post processing such as painting, electroplating, bonding and drilling. Select the size of plastic parts with high dimensional accuracy for analysis to see whether the estimated molding tolerance is lower than the tolerance of plastic parts and whether the plastic parts can meet the requirements. In addition, we also need to know the plasticization and molding process parameters of plastics.

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

　　Molding materials should meet the strength requirements of plastic parts, with good fluidity, uniformity, isotropy and thermal stability. According to the use of plastic parts, molding materials should meet the requirements of dyeing, metal plating conditions, decorative performance, necessary elasticity and plasticity, transparency or opposite reflection performance, bonding or weldability.

　　3. Determine the molding method

　　Direct pressure method, casting pressure method or injection method should be adopted.

　　4. Select molding equipment

　　According to the type of molding equipment to mold, so we must be familiar with the performance, specifications, characteristics of various molding equipment. For example, for the injection machine, the following contents should be understood in terms of specifications: injection capacity, mold locking pressure, injection pressure, mold installation size, ejection device and size, nozzle hole diameter and nozzle spherical radius, gate sleeve locating ring size, maximum and minimum mold thickness, template stroke, etc. see relevant parameters for details.

　　To preliminarily estimate the mold size, judge whether the mold can be installed and used on the selected injection machine.

　　5. Specific structure scheme

　　(1) Determine the type of die plate

　　Such as compression mold (open, semi closed, closed), casting mold, injection mold, etc.

　　(2) Determine the main structure of the die plate type

　　The choice of the ideal die structure is to determine the necessary molding equipment and the ideal cavity number, so that the work of the die itself can meet the requirements of the technology and production economy of the plastic parts under reliable conditions. The technological requirements of 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 plastic parts low cost, high production efficiency, mold can work continuously, long service life, save labor.