Hot-fill packaging preforms up to 96 cavities

Krauss-Maffei says that its Petform technology is making PET preforms for hot-fill packaging in 72- and 96-cavity tooling, surpassing the traditional maximum of 48 cavities for this application. The company sees a growing demand for hot-fill applications in China and Thailand, where the higher cavitation is already in use on its systems (the photo shows an installation in China.)

The vertical clamping used by the Petform systems is the key to overcoming the 48-cavity limit, the company says. The filling temperatures for these containers can exceed 90ºC (194ºF). Therefore, the threads are crystallized before filling to avoid uncontrolled crystallization and inconsistent shrinkage in the neck area during filling.

Krauss-Maffei says tolerances of hot-fill preforms are, of necessity, very close, especially in the neck area, and these can be impacted by even relatively small differences in the mold heating zones. Inconsistent shrinkage generally would result in oval deformation or even bending in the preform neck area. Krauss-Maffei says that the heating circuits in a horizontal molding machine being stacked atop each other creates a chimney effect that can result in temperature fluctuations in the mold.

When using its vertical clamp, says the company, the inevitable heat increase of the various circuits during molding has no influence on the temperature distribution in a balanced mold. Thus the precise tolerances can be held in the preform neck.

Modular design means a Petform system can be customized to optimize its applications. A system is provided as turnkey installation, complete with molds, automation, material handling and cooling water peripherals, and application-specific downstream equipment for products such as cosmetics containers.

High-performance plasticating units and four-stage post-cooling technology are aimed at high levels of productivity and quality in systems from eight to 96 cavities.?RN

Krauss-Maffei
Florence, KY
(859) 283-0200
www.krauss-maffei.de

April 2005