What Is a Mold Temperature Controller?
A mold temperature controller is a device used to maintain the temperature of molds used in injection molding, extrusion molding, and other plastic product molding processes at a constant temperature.
Mold temperature is affected not only by seasonal variations but also by temperature differences between morning and evening. Mold temperature controllers must maintain a constant mold temperature to stabilize the quality of molded products.
This is similar to a mold cooler (chiller). Mold chillers specialize in circulating chilled water to lower mold temperature. On the other hand, mold temperature controllers use oil and water as the circulating medium, making it possible to maintain a constant mold temperature not only at low temperatures but also at temperatures of 100°C or higher.
Uses of Mold Temperature Controllers
Mold temperatures that are too high or too low can significantly affect the quality of molded products. Low mold temperatures cause flow marks, cracks, luster defects, and other problems. On the other hand, too high a mold temperature can cause warpage, dimensional defects, sink marks, etc.
Mold temperature controllers maintain a constant mold temperature and prevent these defects.
Water-based mold temperature controllers can control temperatures up to about 90°C. Oil-based mold temperature controllers can control temperatures higher than that. Oil-based mold temperature controllers are used to control temperatures above that level.
For example, polyvinyl chloride (PVC), polycarbonate (PC), polypropylene (PP), and polystyrene (PS) use water-based mold temperature controllers.
On the other hand, PET (polyethylene terephthalate) and PPS (polyphenylene sulfide), which require control at high temperatures, use oil-based mold temperature controllers.
Principles of Mold Temperature Controllers
- Principle of Temperature Control: Mold temperature controllers keep the mold’s temperature constant through heat exchange by circulating a temperature-controlled medium, such as water or oil, through piping that passes into the mold.
Heat exchange refers to transferring heat energy from the hotter mold to the cooler water or oil medium. The temperature difference between the temperature of the medium entering the mold and the temperature of the medium leaving the mold is one indicator of the performance efficiency of mold temperature controllers.
Water mold temperature controllers use a direct cooling method to control the temperature by controlling the circulation and discharge of water through pipes that pass into the mold. On the other hand, an oil-based mold temperature controller uses an indirect cooling method in which an oil medium circulates in the mold piping, and the temperature of the medium is controlled by the cooling water.
- Usefulness of Mold Temperature Controllers: In injection molding, cooling the hot resin stabilizes the shape of the molded product and allows it to be removed from the mold. Although mold release is possible without a mold temperature controller by releasing heat to the outside air, using a mold temperature controller stabilizes the quality of the molded product and promotes rapid mold release, thereby improving production efficiency.