What is the effect of mold temperature on the formation of plastic products?

A hot mold surface keeps the plastic surface liquid for a long time, enough to create pressure in the cavity. If the cavity fills up and the cavity pressure presses the soft plastic against the metal before the frozen skin hardens, the replication of the cavity surface is high. On the other hand, if the plastic entering the cavity at low pressure is suspended, no matter how short the time is, its slight contact with the metal will cause stains, sometimes referred to as gate stains.

For each plastic and plastic part, there is a limit to the surface temperature of the mold beyond which one or more adverse effects may occur (for example, the component may overflow the burrs). Higher mold temperatures mean less flow resistance. On many injection molding machines, this naturally means faster flow through the gates, gates, and cavities because the injection flow control valve used does not correct this change, and filling will cause higher temperatures in the runners and cavities. Effective pressure. May cause flash burrs. Since the hotter model does not freeze the plastic that enters the edge of the flash before the high pressure is formed, the melt can flash over the ejector rod and spill into the gap of the dividing line. This suggests that good injection rate control is required, and some modern flow control programmers can do this.

In general, an increase in the temperature of the mold reduces the condensation of the plastic in the cavity, making the molten material flow more easily in the cavity, resulting in greater part weight and better surface quality. At the same time, the increase in mold temperature also increases the tensile strength of the part. Many molds, especially engineering thermoplastics, operate at relatively high temperatures. If the mold is not insulated, the heat lost to the air and the injection molding machine can easily be lost as much as the shot cylinder. Therefore, the mold and the board should be insulated and, if possible, the surface of the mold should be insulated. If a hot runner mold is considered, try to reduce the heat exchange between the hot runner portion and the cooled injection molded part. Such an approach can reduce energy loss and warm-up time.

The purpose of the temperature control on the formability and the appearance of the molded article, the physical properties of the material, the forming cycle, etc., are significantly affected by the temperature of the mold core. In general molding, the temperature of the mold is kept low, and the number of shots can be increased. However, the forming cycle related to the shape of the molded article (the structure of the mold) and the type of the finished product also depends on the temperature at which the filling of the mold must be increased.

This is a problem of the molded material, and this requirement only has a cooling rate. The cold time is short, and even if there is a part where the hardening is still soft, the stress caused by the uneven shrinkage can be avoided. That is, proper temperature control can improve the cooling stress properties.