The pneumatically or hydraulically actuated machine needle shut-off nozzles type HP are used in processing of thermoplastics, principally with low viscosity materials such as: PA, PPS, PE, POM,PP. In this nozzle’s favour are:
Cycle time reduction, shut-off at the nozzle orifice, withdrawal while dosing. Finds application in:
Packaging, automobile and leisure industries, medicinal and electronic equipment. Operation:
The assembly integrated actuator (pneumatically or hydraulically activated) controls a nozzle-axis positioned needle via a lever mechanism. The melt flow is therefore process dependently separated at the nozzle orifice. The needle mechanism is constructed in such a way, that with over-pressure an automatic opening of the nozzle is ensured. Modules for filters, mixers and GAIM-applications complete the range of shut-off nozzle products. Prevents:
• Filamentation
• Air pockets during screw retraction
• Material leakage when dosing with a withdrawn injection unit
• Material leakage while vertically injecting Applicable for special applications such as:
• Physical foaming
• Pre-compressing the melt
• Hot-runner injection molding (e.g.. containers, pots) Supported process control:
• Actuator piston position sensors (indicates if nozzle is “open” or “closed”) Productivity factors:
• Controlled, clean shut-off of the melt stream
• Shorter cycle times - increase in productivity
• Increased process reliability and repeatability
• Usability with increased back pressure - improved homogenization
• Add-on capability (on tool side) Options:
• Filter module
• Mixer
• GIT
• Process monitoring with piston position sensors on the actuator | 
