The Steps Of Plastic Mold Design
May 16, 2024
1. Accept the assignment
The task book for forming plastic parts is usually proposed by the part designer, and its contents are as follows:
1. The drawing of the formal parts that has been approved and signed, and indicate the grade and transparency of the plastic used.
2. Specifications 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 molding plastic part, and the mold designer designs the mold based on the task book of the molding plastic part and the mold design task book.
2. Collect, analyze and digest raw data
Collect and sort out relevant parts design, molding process, molding equipment, machining and special processing data for use in designing molds.
1. 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 for plastic parts in terms of appearance, color transparency, and performance, whether the geometric structure, slope, and inserts of plastic parts are reasonable, the allowable degree of welding lines, shrinkage holes and other forming defects, whether there is coating Assembly, electroplating, gluing, drilling and other post-processing. Select the dimensions with high dimensional accuracy of plastic parts for analysis to see if the estimated molding tolerance is lower than the tolerance of plastic parts, and whether plastic parts that meet the requirements can be formed. In addition, it is necessary to understand the plasticization and molding process parameters of plastics.
2. Digest the process data, and 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 part, the molding material should meet the requirements of dyeing, metallizing conditions, decorative properties, necessary elasticity and plasticity, transparency or opposite reflection properties, adhesiveness or weldability.
3. Determine the molding method
Use direct pressure method, casting method or injection method.
4. Select molding equipment
Molds are made 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 an injection machine, 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 sleeve positioning ring size, For the large and small thickness of the mold, the template stroke, etc., see 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 pressing molds (open, semi-closed, closed), casting molds, injection molds, etc.
(2) Determine the main structure of the mold type
The selection of 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 requirements of the process technology and production economy of the plastic part. The technical requirements for plastic parts are to ensure the geometry, surface finish and dimensional accuracy of the plastic parts. The economic requirement of production is to make the cost of plastic parts low, the production efficiency high, the mold can work continuously, the service life is long, and labor is saved.