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Addex Inc., a global supplier of blown-film equipment and components, has launched an enhanced automatic external gauge control (EGC) system for blown-film extrusion lines.The new Tandem external gauge control (TEGC) system combines the gauge control of Addex's EGC air ring with a bubble stabilizing lower air ring, which achieves 15% to 30% greater output compared to Addex's standard EGC system.

PlasticsToday Staff

April 18, 2013

3 Min Read
Addex develops an enhanced automatic external gauge system for blown-film extrusion

Addex Inc., a global supplier of blown-film equipment and components, has launched an enhanced automatic external gauge control (EGC) system for blown-film extrusion lines.

The new Tandem external gauge control (TEGC) system combines the gauge control of Addex's EGC air ring with a bubble stabilizing lower air ring, which achieves 15% to 30% greater output compared to Addex's standard EGC system.

The lower single-lip air ring sits on the die and matches the die's diameter. It is fed by a blower about half the size of the blower needed for a typical air ring. The blower gently cools the bubble and stabilizes it before entering the realm of the upper, dual-lip automatic gauge-control air ring, which is located above it. Addex said the more stable bubble allows for higher output without jeopardizing the gauge control function.

EGCTANDEM.jpgThe upper EGC air ring is 2 inches (50 mm) bigger than the die size. Therefore, a 16-inch (400-mm) die employs a 16-inch (400-mm) single-lip air ring located on the die and an 18-inch (450-mm) EGC air ring situated on top (as shown in photo). The larger diameter for the upper air ring, which is equipped with the gauge controlling features, is needed to accommodate for the blow up ratio.

The remaining components of the Tandem EGC system are the same as those of the standard EGC system. The standard unit is an automatic system that reduces film-thickness variations by up to 70%, typically resulting in a 5% to 6% raw material savings, according to the company.

Addex simplified the original air-ring structure by moving the electronic circuit board (the brains) from outside of the air ring into the plenum area. This integration offers simplicity, enabling the end user or OEM customer to rely on its own control panel if desired. Addex said that an end user or OEM customer can also use its own thickness measuring system and feed it via the Ethernet connection to the air ring.

Other key options for the OEM include mapping hardware and software for the control processor and monitoring devices for the reversing nip position and nip roll speed along with a control algorithm that converts the mapped gauge profile into instructions for the air ring software.

Addex said the EGC system has the most control zones in the industry for air ring-based systems. The number of control zones ranges from 90 to 288 depending on the air ring size.

A scanning actuator horizontally slides as many teeth (control zones) as needed to open or close the air flow channels (vanes) and automatically adjusts the cooling air, thus correcting thickness variation in the blown film.

Just two motors activate all the movable parts in the system compared to other systems, which use one motor per zone. Like the previous EGC air ring, one motor is used to adjust the airflow and the second one adjusts the first motor 360 degrees.

"The Tandem EGC is the culmination of extensive development work and is yet another example of how Addex works continually to devise unique products that help processors increase yield and realize major raw material savings," said Rick von Kraus, president of Addex, in a news release.

Addex Inc., based in Stoughton, MA, was founded in July 1989 as a supplier of components for blown-film production. The company is a manufacturer of many patented blown-film components and systems including manual and automated gauge controls, dies, air rings, internal bubble cooling systems, oscillating haul-offs, and winders, as well as gravimetric blenders and bubble cages.

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