Plastic mold design and manufacturing personnel must carefully carry out mold design according to the above basis and requirements provided by the customer, and the above content will be concretized one by one when designing the mold and expressed in the form of drawings and technical documents. Let’s learn the general procedures of plastic mold design and manufacturing in detail.
1. Plastic mold design and manufacturing diagram and actual analysis and digestion
Before the design and manufacture of plastic molds, first of all, the product drawing or actual detailed analysis and digestion, its contents include:
a. Product geometry
b. Product dimensions, tolerances, and design standards;
c. Product technical requirements (technical conditions);
d. The name and variety of plastics used in the product;
e. Product surface requirements.
2. Confirm the injection model number
The determination of the specifications of the injection machine mainly depends on the size of the plastic products and the production batch, the designer in the selection of the injection machine, mainly considers the plasticization rate, injection volume, clamping force, installation mold production area (injection machine rod spacing), volume ratio, extrusion form and extrusion length. If the customer provides the injection model number or specifications that have been used, the designer should compare its parameters, and if it is too scared to meet the requirements, it should discuss the replacement with the customer.
3. The number of cavity determination and cavity arrangement
The determination of the number of cavities mainly depends on the projected area of the product, the geometric shape (with or without side core), and the accuracy of the product. And then the economics decide. The number of cavities is mainly determined based on the following factors:
a. Product weight and injection machine injection volume
b. Product projection area and injection machine locking force
c. The overall size of the mold and the effective area of the injection machine mounting bracket mold (the distance between the rod of the injection machine)
d. Product accuracy
e. Product color
f. Whether the product has a side core and its treatment method
g. Product production batch (monthly batch or annual batch).
h. Economic benefits; (output per model)
Some of these factors are mutually restricted, and when determining the design plan, it is necessary to coordinate to meet its main conditions. After the number of cavities is determined, the cavity is placed, that is, the position of the cavity is placed. The cavity arrangement involves the mold size, the design of the pouring system, the balance of the pouring system, the design of the core slider mechanism, the design of the plug-in and core, and the design of the heat transfer system. These problems also involve the choice of parting surface and gate location, which needs to be adjusted in the specific design process to achieve a relatively perfect design.
4. Determine the parting surface
Some foreign product drawings also specify the parting surface, but the mold designer must decide many mold designs. In general, the separation surface on a plane is easy to handle, so special attention may be required when touching the separation surface of the three-dimensional part. The selection of its parting surface should follow the following principles:
a. For products that do not affect the appearance of the product, especially those with clear requirements for the appearance, attention should be paid to the impact of typing on the appearance.
b. Help to ensure product accuracy
c. Conducive to mold processing
d. It is conducive to the design of the pouring system, exhaust system, and cooling system
e. It is conducive to product molding, cutting product maintenance, and leaving the product on the moving mold side when opening the mold;
f. Easy installation of metal plug-in
5. Determination of side parting and core pulling mechanism
When designing the side separation mechanism, ensure safety and reliability, and try to avoid interference with the ejector mechanism. Otherwise, set the reflux mechanism in the mold.
6. Design of the pouring system
The design of the gating system includes the selection of the main channel, the determination of the section shape and size of the diverter channel, the selection of the gate position, the form of the gate and the section size of the gate. When the point gate is used, in order to ensure that the diverter falls off, the gate release device should first pay attention to the selection of the gate location when designing the pouring system. The choice of gate location is directly related to the molding quality of the product and the smooth injection process. Choose the gate location according to the following principles
a. The gate position should be selected on the parting surface as far as possible to facilitate mold processing and gate cleaning during use;
b. The distance between the gate position and each part of the cavity should be consistent as far as possible so that the flow is shorter.
c. When the plastic flows into the cavity, the gate position should be relative to the wider and thicker part of the cavity to facilitate the injection of plastic
d. When flowing into the cavity, avoid the plastic directly colliding with the cavity wall, core, and plug-in. In this way, the plastic can quickly flow into various parts of the cavity, preventing the core and plug-in deformation.
e. To avoid the appearance of welding marks in the product, to avoid the appearance of welding marks in the unimportant parts of the product;
f. Gate position and plastic inflow direction, when the plastic flows into the cavity, it should flow evenly along the parallel direction of the cavity, which is conducive to the gas discharge in the cavity;
g. The gate should be set in the part where the seal is easy to remove, and try not to affect the appearance of the product.
The above is the detailed operation of the general procedure of plastic Mold design and manufacturing. If you need more information, you can contact BFY Mold at any time!
