The tendency in extrusion is toward increasingly high mass output at c
onstant high quality and thus enhanced economy. The quality is highly
dependent on the homogeneity of the melt. In contrast to off-line test
ing, an in-line test method of determining the melt homogeneity has th
e advantage that the homogeneity is measured directly together with th
e process parameters; there is no time difference between sampling and
process control.