In the injection molding process, the cooling time of i […]
In the injection molding process, the cooling time of injection molded parts accounts for most of the entire injection molding production cycle, which is enough to prove the importance of cooling to injection molded parts. If the injection molding process is cold and not good, it will often cause warpage or surface defects, which will affect the dimensional stability of the product.
Therefore, the injection molding, compression and cooling time must be reasonably arranged to improve the quality and productivity of injection molded products. When we speak of cooling time, we are referring to the time between the plastic melt and the injection mold cavity, and the time the mold is removed. The time standard for the parts that can be opened and taken out is often based on the fact that the parts are sufficiently solidified, have a certain strength and rigidity, and there is no deformation or cracking when the mold is opened and ejected.
The results show that even if the same material is used for injection molding, the cooling time varies with changes in wall thickness, melt temperature, mold release temperature and injection mold temperature. Therefore, it is still very difficult to calculate the cooling time correctly, and the correct cooling time can only be calculated under appropriate assumptions.
At present, the cooling time of the three reference standards for injection molding is, on the one hand, the temperature of the thickest part of the injection molding of the central layer of the wall part, and the time required for the time-cooled plastic to be below the thermal deformation temperature; on the other hand, it is convenient It is the average temperature in the workpiece when it is cooled to the predetermined temperature of the product when it is molded; the third aspect is that the cooling time of injection mold molding can be based on the temperature of the thickest part of the mold as the standard, that is, it is cooled to its temperature. The time required for the object to be below the melting point.