A new approach to conformal cooling is said to speed molding cycles 20% to 50% and eliminate hot spots and variations in mold surface temperature. This patented evaporative cooling approach is available for license from Ritemp Technologies Pty. Ltd., Edwardstown (Adelaide), South Australia. Instead of conventional gun-drilled cooling channels, large cooling chambers are machined out of the core and cavity sides of the mold. The chambers leave "islands" around ejectors, bolts, etc. Each chamber contains a predetermined amount of water. Air is evacuated from the chamber with a vacuum pump, which allows the water to boil at low temperatures (50 F). Making it easier for water to boil is important because much more heat is removed in the phase change from liquid to gas than in merely heating liquid water. Also, evacuating oxygen from the water eliminates corrosion, say Ritemp sources. At the top of each mold half, a heat exchanger condenses the steam back to water. Chilled water is run through the heat exchanger. The coolant is isolated from the rest of the mold, which does not run cold enough to "sweat." With this system, cooling occurs only where needed in the mold, and mold temperature is highly uniform regardless of its geometry, according to Ritemp. A sensor in each mold chamber measures system temperature. Ritemp supplies a controller to turn water flow to the mold on and off depending on mold temperature. Standard machining is used to hollow out the cooling chamber with no need to follow part contours exactly or achieve a precise surface finish.
Ritemp Technologies Pty. Ltd.
1084 South Rd. P.O. Box 338
Edwardstown (Adelaide) 5072, Australia