Mold processing center

Mold making process Acceptance of the task statement The task statement for molded plastic parts is usually proposed by the part designer, and its content is as follows: 1. The formal drawing of the part after review and sign, and indicate the grade and transparency of the plastic used. 2. Instructions or technical requirements for plastic parts. 3. Production output. 4. Samples of plastic parts. Usually the mold design task book is proposed by the plastic part craftsman according to 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. 2. Collect, analyze, and digest the original data. Collect and sort out the relevant part design, molding process, molding equipment, mechanical processing and special processing data for use when designing molds. 1. Digest the drawings of plastic parts, understand the purpose of the parts, analyze the technical requirements of plastic parts, such as the manufacturability and dimensional accuracy. For example, what are the requirements for plastic parts in terms of appearance, color transparency, and performance, whether the geometric structure, slope, and inserts of the plastic parts are reasonable, the allowable degree of molding defects such as weld marks and shrinkage holes, and whether they are coated or not. Post-processing such as assembly, electroplating, bonding, and drilling. Select the size with the highest dimensional accuracy of the plastic part for analysis, and see if the estimated molding tolerance is lower than the tolerance of the plastic part, and whether the plastic part that meets the requirements can be molded. In addition, it is necessary to understand 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 proposed in the process task book are appropriate and whether they can be implemented. The molding material should meet the strength requirements of plastic parts, and have good fluidity, uniformity, isotropy, and thermal stability. According to the purpose of the plastic parts, the molding material should meet the requirements of dyeing, metal plating, decorative properties, necessary elasticity and plasticity, transparency or opposite reflective properties, adhesiveness or weldability. 3. Determine the molding method to adopt direct pressure method, casting method or injection method. 4. Select molding equipment. Molds are made according to the type of molding equipment. Therefore, you must be familiar with the performance, specifications, and characteristics of various molding equipment. For example, for an injection machine, the following should be understood in terms of specifications: injection capacity, clamping pressure, injection pressure, mold installation size, ejection device and size, nozzle hole diameter and nozzle spherical radius, sprue sleeve positioning ring size, The maximum and minimum mold thickness, template stroke, etc., please refer to the relevant parameters for details. It is necessary to preliminarily estimate the dimensions of the mold and determine whether the mold can be installed and used on the selected injection machine. 5. Specific structure plan (1) Determine the type of mold such as compression mold (open, semi-closed, closed), casting mold, injection mold, etc.

(2) Determine the main structure of the mold type. The ideal mold structure is to determine the necessary molding equipment and the ideal number of cavities. Under absolutely reliable conditions, the mold itself can meet the process technology and production economy of the plastic part. Requirements. The technological requirements for plastic parts are to ensure the geometric shape, surface finish and dimensional accuracy of the plastic parts. The economic requirements of production are to make the cost of plastic parts low, high production efficiency, molds can work continuously, long service life, and labor saving. 3. There are many factors that affect the mold structure and individual mold systems, and they are very complicated: 1. Cavity layout. Determine the number of cavities and their arrangement according to the geometric structure characteristics of the plastic parts, the dimensional accuracy requirements, the batch size, the difficulty of mold manufacturing, and the mold cost. For the injection mold, the precision of the plastic parts is 3 and 3a, the weight is 5 grams, the hardening casting system is adopted, and the number of cavities is 4-6; the plastic parts are of general precision (level 4-5), and the molding The material is partially crystalline material, the number of cavities can be 16-20; the weight of plastic parts is 12-16 grams, the number of cavities is 8-12; and the weight of plastic parts is 50-100 grams, the number of cavities is selected 4-8. The recommended number of cavities for amorphous plastic parts is 24-48, 16-32 and 6-10. When the weight of plastic parts continues to increase, multi-cavity molds are rarely used. For plastic parts with 7-9 accuracy, the maximum number of cavities is 50% higher than the indicated plastic with 4-5 accuracy. 2. Determine the parting surface. The position of the parting surface should be conducive to mold processing, venting, demolding and molding operations, and the surface quality of plastic parts. 3. Determine the pouring system (the shape, location and size of the main runner, sub-runner and gate) and exhaust system (exhaust method, exhaust slot location, size). 4. Select the ejection method (ejector, pipe, push plate, combined ejector), determine the undercut treatment method and core pulling method. 5. Determine the cooling and heating method, the shape and location of the heating and cooling groove, and the installation location of the heating element.