Shear Control Orientation Injection molding essentially applies a dynamic pressure to the melt through a gate, causing a vibrational shear flow of the polymer melt in the cavity, under which the molecular chains or fibers in different melt layers are produced. Orientation and freezing in the workpiece, thereby controlling the internal structure and microscopic morphology of the article, to achieve the purpose of controlling the mechanical properties and appearance quality of the product. The method of introducing vibration into the cavity has two types of auxiliary devices and screw vibration.
1. Auxiliary device vibration
Auxiliary device vibration is to install the vibration device between the mold and the nozzle of the injection molding machine. The injection phase is the same as the general injection molding. Usually, the melt passes through only one gate, the gate piston retreats to keep the flow path unobstructed, and the other piston The other flow path is cut off; after the cavity is filled, the two pressure-preserving pistons start to vibrate at the same frequency under the drive of a separate hydraulic system, but the phase difference is 1800.
Through the reciprocating motion of the two pistons, the vibration is transmitted to the cavity, and the melt in the cavity is cooled while generating a vibration shear flow. Experiments prove that this process can help eliminate common defects of products (such as shrinkage, cracks, surface subsidence, etc.) and improve the strength of weld lines. By using shear control orientation molding technology, by controlling the position and quantity of gates, molecules can be controlled. Or the orientation of the fibers gives a product that is stronger than conventional injection molded articles.