Vertical injection molding machine low speed when the flow is stable, the product size is relatively stable, fluctuations are small, the product internal stress is low, and the product internal and external stress tends to be the same (such as polycarbonate parts immersed in carbon tetrachloride, high-speed injection formation of the parts have a tendency to crack, low-speed non-cracking).
Under slower filling conditions, the temperature difference between the streams, especially before and after the large gate material, is favorable to avoid the occurrence of shrinkage parts and concave parts.
However, due to the longer filling time, which is prone to product delamination and poor bonding, weld line continuation not only affects the appearance but also greatly reduces mechanical strength.
Vertical injection molding machine high-speed injection, the material flow rate is fast. When the high-speed filling is smooth, molten material soon fills a full cavity, the material temperature drops less, and viscosity drops less. Lower-cost injection working pressure can be used, which is a hot material filling posture.
However, it is easy to produce product fat blistering or yellowing, or even burned and scorched, or cause demolding difficulties, or vertical injection molding machine mold filling uneven phenomenon. For high-viscosity plastics, it may lead to melt rupture and cloudy spots on the surface of the parts.
