The injection molding cycle refers to the complete sequence of operations required to produce a single molded part using the injection molding process. It typically consists of the following main stages:
1.Clamping
The mould is closed and clamped with sufficient force to keep it closed during the injection process to prevent the molten plastic from leaking out.
2.Injection
Molten plastic is injected into the closed mold cavity under high pressure. The injection speed and pressure must be carefully controlled to ensure proper filling of the cavity and the quality of the molded part.
3.Packing/holding
After the cavity is filled, additional pressure is maintained for a certain period to compensate for the shrinkage of the molten plastic as it cools and solidifies. This helps to improve the density and dimensional stability of the part.
4.Cooling
The molten plastic in the mold is allowed to cool and solidify. The cooling time is an important factor in determining the production cycle and the quality of the part. Sufficient cooling time must be provided to ensure that the part is fully solidified before ejection.
5.Ejection
Once the part is solidified and cooled, the mold is opened and the molded part is ejected from the cavity. The ejection mechanism must be carefully designed to avoid damaging the part.
6.Mould cleaning and preparation
After the part is ejected, the mold is cleaned to remove any residual plastic, debris, or lubricants. The mould may also need to be sprayed with a release agent to facilitate the ejection of the next part. Then the mould is closed again and the cycle repeats.
The total time for one injection molding cycle can range from a few seconds for small, simple parts to several minutes for large, complex parts with thick walls or intricate geometries.