02. DIE HEADS
Macchi patented Coex Flex die heads are all designed to be extremely compact, with reduced body mass, a result achieved by eliminating the traditional multiple channel radial distributor below the die block. The melt flows from the different extruders are all fed at the same level to the designated entry ports. Each individual layer flow path is machined with a design distribution based on the combined concept of binary melt splitting followed by a traditional spiral-cut lamination zone. With a very low resin inventory volume in the die block and a consequently shortened polymer residence time, this concept also ensures excellent results in terms of layer-to-layer thickness distribution and, as additional benefits, a shorter transition times between product changeovers with less scrap. A further advantage lies in the mechanical aspects of the die-head engineering, where, thanks to the large size and the accuracy of the mating surfaces, a leak-proof sealing is obtained without the need of any kind of gasket or sealing element. In an industry where die disassembly and re-assembly for cleaning are routine jobs, this exclusive Macchi Coex Flex design offers a highly positive contribution toward less expensive and simplified operations.