Radial Wall-Thickness Control System Comes to the Americas | Plastics Technology

W. Müller USA now offers Feuerherm PWDS system for extrusion blow molding in North and Sourth America.

Feuerherm PWDS system is now available in servohydraulic and electric versions through W. Müller USA. Electric actuators are shown here. Source: Feuerherm GmbH

What is said to be the world’s most popular deformable-ring type of radial wall-thickness control is now available in the Americas through W. Müller USA. The company’s German parent, W. Müller GmbH, has formed a partnership with Feuerherm GmbH, inventor of the patented Partial Wall Thickness Distribution System (PWDS) and patented Static Flexible Deformable Ring (SFDR). The two companies, both located in the same German city of Troisdorf, have cooperated for decades, but the new formal partnership makes the Feuerherm systems directly available through W. Müller USA, whose staff has recently been trained in the PWDS/SFDR technologies.

Profiled SFDR unit (1) and exchangeable insert (2). They work together with the PWDS to permit quick changeovers. Source: Feuerherm GmbH

PWDS offers programmed changes in the radial die gap along the parison length. The heart of this system is the dynamic flexible die ring, which is moved with servohydraulic or electrical actuators. Symmetrical or asymmetrical deformations of the die ring help molders optimize material distribution to minimize overall material usage and cycle times. When PWDS is combined with SFDR, these benefits are combined with the ability for quick product changeovers.

The SFDR unit replaces the solid mandrel. The flexible, adjustable unit enables profile modification that can be reproduced at any time without removal of the mandrel tool. This is helpful when changing products and in mold validation, when different profiles can be tested in quick succession. SFDR units are typically equipped with inserts that can be changed in minutes.

Since 1977, the PWDS/SFDR systems have been used in packaging (canisters, jugs, drums, IBS); technical parts (filler pipes, hydrogen liners, solar-panel floaters and more); and blow molded recreational products, toys and furniture.

These systems can be supplied with new W. Müller extrusion heads or retrofitted to existing ones.

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