Manufacture-induced inaccuracies of spinning dies - Do they influence the fineness and structural unevennesses of PA 6 and PET multifilament yarns?

The die in the melt spinning process distributes the whole melt stream into individual small melt streams that pass the die parallel to each other. Th e number of holes in the die determines the number of filaments in the spun fiber bundle. As the whole melt stream (i. e. the total throughput) is enf orced by a precise gear pump (the spinning pump) the sharing out into the s ingle hole throughputs is dependent on the pressure and the flow resistance s of the single holes. Only for constant pressure and equal resistances the single hole throughputs are equal, too. The present peeper deals with the influence of geometrical inaccuracies of the holes in the spinning die on t he fineness and structural variations across the spun fiber bundle.