Overview

“Light-weighting” in the plastic packaging industry is now commonplace as manufacturers adapt to eco-friendly initiatives that also reduce material costs. While reducing the amount of resin in a preform is both an environmentally and financially commendable strategy, the quality and production controls required to maintain consistent production of high-quality preforms must be equally robust.

Common mold maintenance practices such as mold “flashing” often result in injection ‘pin’ deflection. Mold shift results in preforms that appear to be of good quality -- and may even pass basic metrology tests -- but will cause major bottle performance problems downstream.

AVID is pleased to introduce U-TES-P, a preform thickness and concentricity analysis system designed to detect preform quality issues caused by core pin shift/deflection. U-TES-P replaces AVID’s previous preform thickness measurement system, the ‘THIKCHEK.’

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Competing Methods

Several measurement technologies exist for determining preform concentricity, each with drawbacks that make them imperfect for detecting thickness issues. Mechanical and hall-effect gauges (“Magnamikes”) are difficult to use on curved surfaces because they require precise gauge placement and stable part orientation during rotation for repeatable measurement. Laser and vision gauges eliminate the measurement variations caused by operators, but are subject to effects caused by wall surface variations (scratches and surface defects) as well as part opacity and movement.

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AVID has addressed these measurement handicaps and delivers a proper measurement solution for preform concentricity measurement. U-TES-P makes fast concentricity measurements and incorporates a design that ignores optical effects that can cause measurement errors in most available optical thickness devices.

System Operation

The user selects a part from the part library that contains the parameters for all customer parts. The user positions the height of the centering tool to the indicated position via a slide indicator. The preform is then placed onto the centering tool.

Varying height preforms can generally be accommodated with only 1 or 2 change-out pieces. Concentricity measurement is available to the operator following measurement (individual thicknesses or max/min/avg thickness measurements are not provided by the system).

Configurations

The basic U-TES-P is available as a manually loaded standalone tool that plugs into an existing customer PC. The system is also available in the U-TES-P AUTO configuration featuring an autoloading system that can accommodate up to 196 preforms. The system is also available as an optional integrated module for the AVBIS 3000P automated precision preform measurement system. Contact AVID for more information.