Adjustable Feedblock Boosts Productivity in Coextrusion by Fine-Tuning Layer Thicknesses without Need for Flow Inserts

DÃœSSELDORF: A new-generation feedblock for flat-die coextrusion simplifies the fine-tuning of layer thicknesses, reducing production downtime for structures from the simplest sheet to complex packaging films, it was announced by Extrusion Dies Industries, LLC (EDI) at K 2010 (Hall 2, Stand G-06).

A feedblock combines melt streams from separate extruders into a multi-layer "sandwich" that the extrusion die subsequently distributes to target product width. The new Ultraflow® V feedblock has adjustable "combining planes" located where the melt streams join the central flow channel. The combining planes can operate in two modes, each with a different advantage in terms of ease and adjustability:

o Eliminating feedblock adjustment by the operator. By leaving the adjustable plane in free-floating mode, operators can let the position be determined directly by the equilibrium pressure developed by flow from the extruders. "The combining plane responds to the pressures of the different mass flows from the extruder by achieving a state of equilibrium reflecting these differences," said John A. Ulcej, president of EDI. "In this way, a change in flow from one of the extruders causes a readjustment of the combining plane at the point where materials merge."

o Optimizing layer-to-layer interfaces. For polymers whose interaction at the point of confluence poses the possibility of disrupting or compromising the multilayer structure, the adjustable plane can be moved manually to fine-tune polymer flow. Shafts extending from outside the feedblock into the centers of the adjustable planes provide ease of operation. Simple settings will change the adjustable planes from free-floating mode to varying levels of responsiveness to melt flow pressure. Once adjusted, an adjustable plane remains in a fixed position.

"Our standard Ultraflow feedblock is an industry workhorse that enables processors to fine-tune layer thicknesses by interchanging specially machined flow inserts, without having to disassemble the feedblock," said Ulcej. "The new Ultraflow V feedblock eliminates even this step by using built-in combining planes. It is, in addition, a compact device, easy to disassemble and clean, and streamlined for optimal flow."

Ultraflow V feedblocks can be designed for any number of extruders or layers. The photo accompanying this news release shows an Ultraflow V feedblock designed for a three-layer structure with three extruders. Inside it are two combining planes for the outer-layer melt streams, while the stream for the core layer enters the feedblock via the central channel.

Extrusion Dies Industries, LLC is a leading international supplier of flat dies for sheet, film, extrusion coating, fluid coating, and pelletizing. The company designs and manufactures dies, feedblocks, deckling systems, vacuum boxes, and related equipment. Its subsidiaries include EDI GmbH in Reichshof-Wehnrath, Germany, and EDI China in Shanghai. In the U.S.A., Germany, and China, EDI operates facilities dedicated to reworking its own dies and those built by other suppliers, and it has licensed a fourth rework facility in Japan. Headquartered in Chippewa Falls, Wisconsin, U.S.A., EDI is focused on supplying the global market. Visit and E-mail:

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