Neck Height Control

Automatic Neck Height Control for HDPE / MDPE High Stalk Bubbles for Improved Film Properties and Production Consistency

How it works
The control feature uses an ultrasonic sensor facing the bottom of the bubble flare to measure neck height, then maintains the set point to within +/- 0.25 inches (6mm) via regulating the air ring blower speed. Neck Height Control is also dependant on feedback provided from the LF-Sizer’s layflat sensors for complete bubble control.

Together with the LF-Sizer, it manages both layflat and neck height during startup, hole recovery and normal production. This coordination reduces time to production and improves production rate; when both width control and neck height are easily and automatically controlled, operators gain the confidence to increase extrusion speed without fear of losing bubble control or producing out of spec film.

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Benefits to Implementation

Controlling and maintaining neck height on high or medium stalk bubbles directly correlates to improved consistency in HDPE / MDPE film dart impact and other film properties related to neck height. See case study figure 1.

Beyond consistent film properties and elimination of dart impact failures, benefits that customers can expect in parallel with the LF-Sizer include increased production due to improved uptime thanks to a reduction in bubble breaks via automated width control and bubble break recovery. See case study figure 2.

Because neck height and layflat are related, by controlling both bubble width and neck height, complete layflat control is achieved.  The result is better looking rolls, in spec production, fewer customer returns, and faster start-up / job changes.

*Case study based on implimentation of DRJ LF-Sizer with Neck Height Control, and also new air ring


Neck Height Control requires and integrates with automatic width control as provided via the DRJ LF-Sizer. Integration to the air ring blower (varying blower speed to control neck height) is via standard serial data communication to a Yaskawa A1000, P1000 or V1000 inverter.

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