Problems with some hot runner technologies are that heat loss through the nozzle can be 40 percent. The heater overheats plastic at the middle of the nozzle.

Heat bypasses the edge and goes into the mold and the plastic can degrade.
New nozzle technology1 with a patent-pending design dramatically reduces the typical heat loss from the nozzle into the mold. The encased thermally conductive carbide tip forms an extension of the nozzle shaft drawing heat from heater directly to tip. The heater is controlled by a separate thermocouple for accurate tip temperature reading. This design gives the nozzle the ability to provide accurate and lower molding temperatures for sensitive materials like 30 percent GF Nylon, producing stronger parts while not degrading the plastic material.

It has four different materials, excluding the heater and thermocouple. The design uses thermally conductive carbon and two of the materials are custom sourced. The materials function in a manner similar to the well known and thermally conductive beryllium copper.

The materials are not identified in the patent-pending. As is customary, the patent application is reported to include enough information for the patent to be awarded, but not enough to disclose the vital art to competitors.

The manifold part and heater system is designed to eliminate sharp corners. The system incorporates easy to bend nickel heaters and cast transition plugs. This approach attempts to push technology to its limit in terms of alloys, high temperature applications and narrow operating windows. Heater life increased significantly.

One application example is a paint container lid being molded of 0.3 melt flow index (MFI) high density polyethylene (HDPE). Part weight is 140g. The single-cavity mold uses three drops. A free flow tip was selected for better flow, as this extrusion grade of very low MFI HDPE is difficult from a flow standpoint. The new nozzle was selected to cope with this very high pressure application.

Superior nozzle technology is key to the process. The net result is shorter molding times and shorter cycle times. Maintaining consistent heat at lower process temperatures inside the nozzle is the key to success in molding the material efficiently.