There are many relevant conditions for precision inject […]
There are many relevant conditions for precision injection molding, such as: plastic materials, injection molds, injection molding technology and injection equipment are the four basic factors that affect precision injection molding. So what are the characteristics of precision injection molds?
The accuracy of the injection mold mainly depends on the high precision of the mold cavity size, the accuracy of the cavity positioning or the accuracy of the parting surface. General dimensional tolerance precision, injection mold should control product dimensional tolerance below 1/3.
Workability and rigidity. In the mold structure design, the number of cavity should not be too much, the bottom plate, support plate and cavity wall should be thick to avoid elastic deformation of parts under high temperature and pressure.
In terms of product demoulding capability, injection molds should use fewer cavities, fewer, shorter flow channels and higher finishes, which is beneficial to mold demolding.
The precision mold material is alloy steel with high mechanical strength. The materials for manufacturing the cavity and the flow channel must undergo strict heat treatment, and materials with high hardness (formed parts should reach about HRC 52), good wear resistance, and strong corrosion resistance are selected.
The mold used for precision injection molding should meet the requirements of product size, accuracy and shape. However, even if the accuracy and size of the injection mold are consistent, the actual size of the plastic product will not be consistent with its mold, because there will be different shrinkage. Therefore, effectively controlling the shrinkage of plastic products is a very important part of the precision injection molding process.
The reasonable design of the injection mold will directly affect the shrinkage of plastic products. Because the size of the injection mold cavity is determined from the size of the plastic product plus the estimated shrinkage. The values in the recommended range are not only related to the shape, position and distribution of the injection mold gate, but also related to the shape and size of engineering plastics and plastic products and the distance and position of the gate, and are related to the cooling distribution system of the injection mold closely related.
The main factors affecting plastic shrinkage are heat shrinkage, phase change shrinkage, orientation shrinkage, compression shrinkage, and elastic recovery. These factors are related to molding conditions or operating conditions.
Precision injection molding technology is the main key production technology of plastic parts, and the design of precision injection mold is the main component of the production technology. Reasonable design of precision injection mold is the basis and premise for obtaining precision products.