| 摘要 |
A foamable synthetic plastic is extruded through a heated extrusion tool (die) and into a preferably water-cooled following calibrator (not shown) arranged following said tool, the outlet speed of the unfoamed plastic melt being determined in a feeding zone within the tool by the width and length of gaps (15, 16) formed by means of one or more cores e.g. core (12) and core extension (13), and the feeding zone being followed in the tool by an expansion zone (19, 20), of which the cross-section amounts to 45% to 96% of that of the following calibrator, which is only reached after feeding through a free path length. The extruded article (Figure 1 not shown) comprises a window cill, provided with an unfoamed exterior skin extruded from tool passage (17,8). <IMAGE> |
