Needle Valve Control Systems

NVS — Needle Valve Control System

NVS (Needle Valve System) is the add-on device that manages the opening and closing timing of needle valve nozzles in a hot runner system. It works integrated over Ethernet with the VARIO, fitron TP and JETmaster TP control units (software version 3.0 and above). No separate display is needed — the data is shown on the interface of the existing control unit.

Cascade (sequential) injection

When a large or long part is filled from a single point, the melt loses pressure towards the end of the flow path; a weld line forms where two flow fronts meet.

In cascade injection several nozzles come into play in sequence: as the melt front advances, the next nozzle opens at the exact moment the front reaches it. The result:

• The weld line disappears or becomes invisible
• Because the flow path is shorter, the required injection pressure drops
• The clamping force requirement falls — a larger part on a smaller machine
• As the pressure distribution is balanced, warpage is reduced

For this to work the nozzles must be timed precisely; NVS takes on that task.

Triggering modes

Stroke-based triggering works from the actual screw position, which makes it more reliable in terms of repeatability from cycle to cycle.

The difference between Standard and Plus

In addition to the standard models, the Plus versions offer end position checking and solenoid valve monitoring: the valve is verified to have actually opened and closed, and an alarm is raised in case of deviation. They are preferred on critical parts and on lines with automatic quality sorting.

Technical specifications

More on cascade injection: What is a hot runner system and what are its advantages? · The system as a whole: hot runner control systems