Mold temperature is the most important variable in injection molding - regardless of the type of plastic that is injected, it is essential to ensure that the mold surface is basically wetted. 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 is hardened, the replication of the cavity surface is high.
On the other hand, if the plastic entering the cavity under low pressure is suspended for a short period of time, its slight contact with the metal causes a stain, sometimes called a gate stain.
For each plastic and plastic part, there is a temperature limit on the surface of the mold, beyond which one or more adverse effects may occur (eg the part can spill over the burrs). Higher mold temperatures mean less flow resistance.
On many injection molding machines, this naturally means faster flow through the gate and cavity because the injection flow control valve used does not correct this change, and faster filling leads to higher effectiveness in the runner and cavity pressure.
May cause flash burrs.As the hotter model does not freeze the plastic that enters the flash edge area prior to high pressure build up, the flash may flash over the top of the ejector bar and spill into the parting line gap, indicating the need for Good injection rate control, and some modern flow control programmer can indeed do this.
In general, increased mold temperatures reduce the plastic's ability to condense within the mold cavity, allowing the molten material to flow more easily within the mold cavity, resulting in greater part weight and better surface quality, while increasing mold temperature also Will increase the tensile strength of the parts.
Mold insulation method
Many molds, especially engineering thermoplastics, operate at relatively high temperatures, such as 80 degrees Celsius or 176 degrees Fahrenheit. If the mold is not insulated, the heat lost to the air and the injection molding machine can be easily combined with the shooting pot As much as lost.
Therefore, to insulate the mold-skeleton plate from the heat of the mold surface if possible, consider reducing the heat exchange between the hot-runner section and the cooled injection-molded part if one considers the hot runner mold. Such a method can reduce Energy loss and warm-up time.