Researchers at BTRA developed nondestructive tests to determine hole profile diameters in spinnerets. The method also helped determine the causes of filament breaks during viscose fiber extrusion. The profiling procedure involved taking polymer impressions of the spinnerets. After immersion in a silicon oil, the technician immersed the spinnerets in a solution of methyl methacrylate dissolved in chloroform for 5 minutes. Pressure applied from the trumpet side of the spinneret extruded polymer from the face side. Polymer remaining around the spinneret set for 48 hours to create a cast impression. Examination of the extruded filaments included measurements of filament diameter with an optical microscope, measurements of conditioned and wet tensile properties with a Zwick Tensile Tester, determination of oven dry strength properties, measurement of frictional properties with a Dyanfil M Tester, X-ray diffraction studies, and observation of morphology by circularly polarized light microscopy. Examination of the spinneret castings included analyses of surface topography using a scanning electron microscope. Photomicrographs showed that the quality of filaments depended on the wear and the surface topography of the spinneret. Different spinnerets, however, produced no significant variations in such physical properties as strength, elongation, and average diametrs for filaments extruded under identical conditions. The coefficient of friction between the spinnerets and the filament was higher for old spinnerets. Sudden increases in fibrousness, which may be caused by a complex combination of flaws in spinnerets morphology and improper processing conditions, caused fiber breakage. 5 refs.