By Andy from Baiyear factory
Upated September 22, 2022
Plastic molds are tools that match plastic molding machines in the plastics processing industry to give plastic products complete configurations and precise dimensions.
How to do general plastic mold design?
Accept the task book
The task book for molding plastic parts is usually proposed by the part designer, and its content is as follows: 1. The formal parts drawing that has been reviewed and signed, and the grade and transparency of the plastic used are indicated. 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 for molding plastic parts, and the mold designer designs the mold based on the task book for molding plastic parts and the mold design task book.
Collect, analyze and digest the original data
1.Collect and sort out the relevant parts design, molding process, molding equipment, machining and special processing data for use in designing molds.
2.Digest the drawings of plastic parts, understand the use of the parts, and analyze the technical requirements of plastic parts such as processability and dimensional accuracy. For example, what are the requirements of plastic parts in terms of appearance, color transparency, and performance, whether the geometric structure, inclination, inserts, etc. of plastic parts are reasonable, and the allowable degree of molding defects such as weld lines and shrinkage holes , with or without post-processing such as painting, electroplating, gluing, drilling, etc. 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 formed. In addition, it is necessary to understand the plasticization and molding process parameters of plastics.
3.Digest the process data and analyze whether the requirements for the molding method, equipment model, material specification, mold structure type, etc. 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. Depending on the purpose of the plastic part, the molding material should meet the requirements of dyeing, metal plating conditions, decorative properties, necessary elasticity and plasticity, transparency or conversely reflective properties, adhesiveness or weldability, etc.
4.Determine whether the molding method is direct pressing, casting or injection.
5.Selection of molding equipment The mold design is carried out according to the type of molding equipment, so it is necessary to be familiar with the performance, specifications and characteristics of various molding equipment. For example, for injection machines, the following should be known in terms of specifications: injection capacity, clamping pressure, injection pressure, mold installation size, ejector device and size, nozzle hole diameter and nozzle spherical radius, gate The size of the sleeve positioning ring, the maximum and minimum thickness of the mold, the travel of the template, etc., see the relevant parameters for details. It is necessary to initially estimate the dimensions of the mold and determine whether the mold can be installed and used on the selected injection machine.
Specific structure plan
1.Determine the type of mold, such as pressing 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, the ideal number of cavities, and under absolutely reliable conditions, the work of the mold itself can meet the process technology of the plastic part and production economy requirements. The technical requirements for plastic parts are to ensure the geometric shape, surface finish and dimensional accuracy of the plastic parts. The economic requirement of production is to make plastic parts low in cost, high in production efficiency, continuous in mold operation, long in service life, and labor-saving.
3.Determine the parting surface
4.The position of the parting surface should be conducive to mold processing, exhaust, demoulding and molding operations, and the surface quality of plastic parts.
5.Determine the gating system (shape, position and size of main runner, sub-runner and gate) and drainage system (draining method, location and size of drainage groove).
6.Select the ejection method (ejector rod, ejector tube, push plate, combined ejection), and determine the side concave treatment method and the core pulling method.
7.Determine the cooling, heating method and the shape and position of the heating and cooling groove, and the installation position of the heating element. According to the mold material, strength calculation or empirical data, determine the thickness and shape of the mold parts, shape structure and all connections, positioning, guide position.
8.Determine the structural form of the main forming parts and structural parts
9.Consider the strength of each part of the mold, and calculate the working size of the forming part. If the above problems are solved, the structural form of the mold will naturally be solved. At this time, you should start to draw a sketch of the mold structure to prepare for the formal drawing.
End of the news
Mold design and manufacture is a very cumbersome and workload-intensive project, which requires the support of a strong R&D team. Baiyear has a strong mold R&D team, and we can efficiently design molds that satisfy customers. Due to the too many words, about molds Design more content, will continue to discuss in the next news.
Post time: Sep-28-2022
