How does the internal flow channel structure of Air-Sealed Preform Mold affect the quality of preforms?
Publish Time: 2024-11-05
The internal flow channel structure of Air-Sealed Preform Mold plays a vital role in the production of preforms and has many effects on the quality of preforms.
First, the shape and size of the flow channel are directly related to the flow state of the plastic melt. A reasonable flow channel shape, such as a circle or an optimized polygon, can make the melt flow at a uniform speed and pressure distribution. If the flow channel shape is irregular or there are sudden changes, the melt will generate turbulence during the flow process. This may cause the local melt flow rate to be too fast or too slow, resulting in uneven material distribution in different parts of the preform, which in turn affects the density consistency of the preform. For example, in the narrow part of the flow channel, the melt flow rate is accelerated, which may cause the density of the preform part here to be lower, affecting its strength.
The diameter of the flow channel is also critical. A diameter that is too small will increase the flow resistance of the melt and cause excessive pressure loss. This may prevent the melt from completely filling the mold cavity, causing defects such as short shots in the preform, affecting the integrity and dimensional accuracy of the preform. If the diameter is too large, the melt stays in the flow channel for too short a time, and the heat uniformity cannot be fully obtained, which may cause temperature differences inside the preform, causing uneven shrinkage, warping and deformation, and other problems.
In addition, the roughness of the flow channel affects the quality of the preform. The rough flow channel surface will cause greater friction when the melt flows. On the one hand, it may cause local overheating of the melt, causing the preform to have appearance quality problems such as scorch marks; on the other hand, the friction will disrupt the flow layer of the melt, destroy the stability of the melt, affect the uniformity of the microstructure inside the preform, and reduce the physical properties of the preform, such as toughness and transparency. Therefore, optimizing the internal flow channel structure of the Air-Sealed Preform Mold is crucial to improving the quality of the preform, ensuring the smooth progress of the subsequent bottle blowing process and the final quality of the bottle.
