In a mold for small parts the pitch dimension of the hot runner tips determines the mold size. To reduce the size it is necessary to screw the tips directly into the manifold.

The natural balancing is achieved by a special distribution device. A radially milled cylinder distributes the melt to each tip with the same flow length. This concept allows a fully balanced hot runner system in limited space.

With technical resins—particularly those containing flame-retardant additives—it is very important to achieve a short residence time of the material in the manifold. Lower pressure loss and short residence times actually contradict each other. For a lower pressure loss a large flow is required and for short residence times a small flow channel. With the externally milled manifold cylinder it is possible to create the channels in a way that enables a compromise to be achieved between these two features.

With critical materials it also is necessary to calculate the residence time and the pressure drop in the system. There are many of calculation programs on the market that can help to pinpoint the best compromise.

The cylinder is mounted on the body of the manifold and heated by a cartridge at thecenter. Minimal tolerances and accurate manufacture—together with special sealing plugs—make sure there is no leakage in the system.