Testing: Thickness Measurement & Dimensional Gauging in One System for Plastic Containers

An all-in-one measurement system for plastic containers and preforms is the latest development launched by Agr International, Butler, Penn. The Gawis 4D is Designed to automate a number of critical bottle and preform measurements into a single operation, the Gawis 4D laboratory test system provides a new level of measurement capabilities to support the design, process and quality management of plastic containers and preforms. 

The Gawis 4D is two systems in one; a thickness measurement system, and a dimensional gauging device. This system incorporates the latest optical gauging and thickness measurement technology, in combination with automation, to simplify container measurement operations while maximizing testing throughput. It is designed to provide broad measurement capabilities on a wide range of plastic containers and preforms with unmatched accuracy, repeatability and operational throughput. 

A major design emphasis for the Gawis 4D is to provide measurements with a level of precision and repeatability that not only can document dimensions of production containers but also have sufficient precision for the qualification and management of molds.  The vision measurement technology incorporated in the Gawis 4D utilizes high pixel density camera components in combination with enhanced telecentric optics and lighting.  This combination provides a very crisp edge shadow, making it possible to achieve the highest dimensional precision and repeatability as well as a very low percent of process variation for individual measurements.

The unique design of the Gawis 4D imaging system, along with advanced measurement algorithms, provides the capability to measure an extensive range of finish dimensions on bottles and preforms.  Jobs can be configured for single or multiple combinations of measurements without sacrificing throughput. A large library of industry standard finish measurement routines is provided with each system that are each customizable to meet the needs of the application.

Thickness measurement in the Gawis 4D utilizes two approaches. For translucent materials, the Gawis 4D incorporates an all-new, patent pending Integrative Thickness Measurement method.  This method takes advantage of the full IR bandwidth and expands the capabilities of the system  to provide measurements on translucent plastic materials that were previously not possible with non-contact measurement.  With this capability, most PE, PP, and heavily colored PET containers that have IR light transmission as low as 5% can now be measured.

For PET bottles, preforms and most transparent materials, the system incorporates Agr’s traditional IR reference/absorption thickness measurement technology.  This technology is widely used in hundreds of Agr measurement systems worldwide for measuring material distribution in bottles and preforms in the laboratory and on-line systems. 

Regardless of the methodology, Gawis 4D offers a means to perform measurements that are fast and precise with un-matched repeatability. Additionally, this system offers a wide range of measurement options including thickness at single or multiple discrete points anywhere on the sidewall or heel of the bottle or the ability to perform complete vertical or horizontal (circumferential) scans for analyzing material distribution.   

Agr has developed AutoJob, a patent pending feature on the Gawis 4D that is designed to simplify job setup by providing automated recognition of key finish measurements on a bottle or preform sample.  With this feature, the operator simply selects the AutoJob mode and the work of locating and identifying finish features is performed automatically.  The Gawis 4D scans the sample, identifies the standard finish measurements for that sample and incorporates them into the job within a matter of seconds.  The operator can adjust the selection, add control limits to the selection and incorporate additional measurements as necessary. This feature greatly accelerates job creation, saving hundreds of labor hours through the course of a year.

Industry 4.0 standard communication protocols have also been incorporated into the Gawis 4D to improve communications and support Industry 4.0 objectives.  This capability facilitates advanced communication with other devices, to share data, support remote job change and interface with factory robotic handling systems without operator intervention.