Vacuum-assisted hot-runner nozzles that eliminate air or gases during two-shot overmolding are new from HRS Flow Hot Runner Systems NA Inc., Windsor, Ont. Unveiled at the recent Euromold exhibition in Frankfurt, Germany, this approach is said to bring better filling at lower pressure, improved part aesthetics, reduced flashing, and potential for longer mold life by reducing chemical attack. The vacuum nozzles are for use only with HRS's M series and come in two versions, one with a vacuum applied after the first-shot valve pin, and a second version with a vacuum chamber for each pin. The system has a titanium ring that makes contact between the nozzle and the mold. The system also requires a new heater layout, new geometry for the tip, ring nut, and bushing, and new materials for those components. HRS also developed its new Fail-Safe Controller for use with dual thermocouples and heaters to prevent operating interruption in case of thermocouple failure. The controller monitors the thermocouples in the manifold or nozzle every 10 millisec and decides which of the two thermocouples to use. In case of thermocouple failure the controller switches to the redundant thermocouple for nonstop operation. The dual design has the same dimensions as a single-heater/thermocouple system.
HRSflow Hotrunner Technology
4570 Rhodes Dr. Unit 100 Windsor N8W 5C2, Ontario, Canada
Phone (519) 973-0212 Fax (519) 973-1639