CHIPPEWA FALLS, WIS. - Flat-die products developed in the past five years will generate about half the expected $40 million in sales this year at Extrusion Dies Inc., and EDI recently announced more news: A new coextrusion feedblock, called Proteus, adjusts the rate of polymer flow in small increments, without splitting the melt stream. A series of valves, each of which can be raised and lowered into the flow channel through tapered holes, which gradually come together to make a single slot, give great flexibility to the feedblock.
In multilayer film and sheet extrusion, a feedblock accepts different polymers, arranges them into parallel layers and feeds the layers into the die. EDI said Proteus is more refined than conventional feedblocks, which manipulate the layers using restrictor bars or profiled pins that can be rotated.
Splitting the stream can cause weld lines and quality problems, the company said. EDI has applied for patents.
EDI is developing commercial dies with the ``flexible preland'' technology that fine tune the melt in the preland section, instead of at the die lips.
Markets include optically clear sheet, coextruded sheet and film with thin skin layers, coated web products and products based on heat-sensitive polymers. It remains in the early stages of development. Robert Barfknecht, president and chief executive officer, said EDI will continue to test its own restrictor bar technology, but the preland system may even supersede it.
Harry Lippert, product development manager, said Eastman Chemical Co. of Kingsport, Tenn., has expressed interest in it for making glycol-modified PET sheet. EDI is licensing the preland technology from Kunststoff-Verfahrenstechnik of Rossdorf, Germany.
In conventional systems, EDI said, as molten polymer enters the die, the primary manifold distributes transversely to form a wider stream, with the preland adjusting pressure and speed. Adjusting the flow before the die eliminates the need to change the die gap, which causes a large pressure drop, according to EDI.
EDI recently obtained a U.S. patent on its Multiflow V hybrid coat-hanger die, which was introduced two years ago. Traditional coat-hanger manifolds have a Y shape. Multiflow is shaped like a T. That makes it possible to arrange the bolts that secure both halves of the die, in a straight line parallel to the die opening, and EDI claims this gives a uniform die body deflection at the die opening, preventing clam shelling.
EDI introduced a fast deckle system with a sliding wedge and a special seal pressed against the die opening. It prevents leakage while allowing the deckle - a device which changes the width of plastic coming out of a flat die - to move back and forth by simply turning a threaded rod.
Top EDI executives announced the products at a Sept. 11 news conference at EDI headquarters in Chippewa Falls.
Barfknecht said EDI makes 600 new dies a year for sheet and film, coating and strand extrusion.
The dies also are used to extrude vinyl siding, which is extruded as a sheet, then post-formed into its finished shape.
EDI claims to have 60 percent of the market for flat dies in the United States and 30 percent of the global market, measured in units. EDI exports more than half its dies.
EDI, which turned 25 years old this year, has doubled its sales over the past five years. Barfknecht said EDI expects 1996 sales of $40 million.
Barfknecht said EDI recently set up its metalworking machines into three work cells. A 10,000-square-foot expansion completed in 1991 brought the total size of the Chippewa Falls plant to 85,000 square feet.
Each die is custom made in a process that fuses high-tech engineering with craftsmanship. EDI machinists have an average of 17 years of experience.
EDI has 210 employees.