Hot runner molds should be considered whenever gating flexibility,cycle efficiency,and material efficiency are important. In a hot system,the feed system is encased in a heated channel so that the plastic remains molten during the molding process..Since the plastic dose not cool in a hot runner system,there is no need to:
1.plasticize the melt that would be required to fill the feed system,
2.inject the material that would fill the feed system
3.wait for the material in the feed system to cool
4.open the mold a substantial amout to remove the feed system,or
5.de-gate the feed system fromm the molded produces.
For all these reasons,it is not uncommon for the hot runner molds to operate with 20% faster cycle times and 20% less material scrap than a conventioinal two-plate or three-plate cold runner mold.However,hot runner molds do require a higher initial investment than either two-plate of three-plate molds.and also require controllers and energy to maintain a unfrorm melt temperature.