Elements of blow molding influence
Influencing factors in the process of making tube billet
Material selection, temperature control, screw speed, die
⑴ Material selection
① Melting index: a low melting index can avoid sagging tube billet, but it should not be too low, otherwise it is prone to unstable activities.
② Molecular weight dispersion: wide molecular weight dispersion is conducive to the production of high-quality tube billets.
③ Tensile viscosity: The material whose tensile viscosity increases with the increase of tensile stress is conducive to blow molding.
⑵ Temperature control
High temperature type billet sagging severe; Low temperature rough appearance, poor plasticization, cooling too fast; Choose the right temperature.
(3) Screw speed
High extrusion speed can improve the output and reduce the sag of the billet, but the speed is too fast and unstable activities are easy to occur, and the screw speed should be determined by the detailed material.
⑷ die
The appearance of the mouth mold is clean and free of foreign bodies. The diameter of the mouth mold should be selected according to the size of the product.
