Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a fluoropolymer process aid by means whereby the weight average particle size of the fluoropolymer is greater than 2 microns as it reaches the extruder die entrance. At least one of the beads constitutes a locking bead consisting of a substantially closed hollow shell with a pair of aligned holes sized to slideably receive the support. Of the plurality of sensor means, at least one of said sensors is located in a position upstream of the excitation source location, and additionally a second of said plurality of sensors is located in a position downstream of the excitation source. A value is determined based on the classifying results, and a mathematical operation is performed on the time series vector and the determined value.