| 摘要 |
<p>The extrusion head includes an upper disc and surrounding annulus having cooperating indentations in adjacent edges defining pairs of elongate slots inclined towards each other in an inwards direction, superimposed on a lower disc and surrounding annulus likewise indented to form pairs of elongate slots inclined towards each other in an outward direction. The crossing points of corresponding slots of the upper and lower disc/annulus assemblies define rectangular apertures through which melt is extruded to produce filaments. Relative movement of the discs and associated annuli varies the crossing points of the slots and therefore the relative positions of the apertures, causing the filaments to intertwine.</p> |
