Machine shut-off nozzles
Machine needle shut-off nozzle type NE (Elastomer) - pneumatic actuation
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There are multiple fields of LSR applications and they are rising in importance. LSR molded parts are frequently seen in the automobile industry, home and sport components, pharmaceutical, medicine and electronic industries. The pneumatically controlled nozzle type NE has a needle shut-off mechanism which stops the melt stream directly at the mold interface. Rubber, liquid silicone rubber and other elastomers can be processed without fear of premature vulcanization due to the nozzle's integrated cooling system, which uniquely regulates temperature through the entire nozzle. The nozzle can also be fitted with an interchangeable diving tip for cold channel applications. The type NE nozzle is suitable for processing with injection pressures of up to 3,000bar and an injection rate of 500cm3. It is designed to allow for easier cleaning and a simple installation. It has been also optimized for melt-flow which results in less friction on the processed elastomer. It is available in custom lengths. Advantages of the needle shut-off nozzle type NE Prevents: Productivity factors: |
Machine needle shut-off nozzle type SHP - spring operated
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The spring actuated machine needle shut-off nozzles type SHP are used in processing of thermoplastics, principally with low viscosity materials such as: PA, PPS, PE, POM, PP. Prevents: Productivity factors: Option: |
Machine bolt shut-off nozzle type BHP - pneumatic / hydraulic actuation
The pneumatically or hydraulically actuated machine bolt shut-off nozzles type BHP are used in processing of thermoplastics.
In this nozzle’s favour are:
Cycle time reduction, shut-off in the nozzle of the melt-stream while withdrawing or dosing. With the BHP nozzle Herzog has designed a system which allows a single throughgoing melt flow channel. Therefore a much bigger flow channel is possible and that is responsible for a reduced pressure drop. With this single channel principle the so called “Memory effect” can be avoided. With the single channel system a cleaning of the unit is done within very short time (similar to an open nozzle).
Finds application in:
Packaging, automobile and leisure industries, medicinal and electronic equipment.
Operation:
The assembly integrated actuator (pneumatically or hydraulically activated) controls a radial positioned bolt via a lever mechanism. The melt flow is therefore process dependently separated. The bolt mechanism is constructed in such a way, that with overpressure an automatic opening of the nozzle is ensured. In contrast to a needle shut-off system, the separation takes place further back. Because of this a longer bore exists between the nozzle orifice and the shut-off unit. For some applications this may not be suitable.
Modules for filters, mixers and GAIM-applications broaden the range of shut-off nozzle
products.
Prevents:
• 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
Supported process control:
• Actuator piston position sensors (indicates if nozzle is “open” or “closed”)
Productivity factors:
• 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
Machine needle shut-off nozzle type A(S) - spring operated
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The original needle shut-off nozzle from herzog® which has over the years enabled processors increase productivity. Strong, reliable and above all economical, it can be adapted to any machine type with the simplest of installations. The nozzle operation is melt pressure dependant. The axial aligned needle is held in the closed position by spring force. Once the injection pressure rises above 200 bar, it will overcome the spring force and open the nozzle. Prevents: Productivity factors: Options: |
Machine needle shut-off nozzle type HP - pneumatic / hydraulic actuation
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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: Finds application in: Operation: Modules for filters, mixers and GAIM-applications complete the range of shut-off nozzle products. Prevents: Applicable for special applications such as: Supported process control: Productivity factors: Options: |
