| 摘要 |
The method consists of: providing an elongate member (tracer) of a material which is substantially inextensible or extensible to a foreseeable extent, feeding the member to the extrusion head of an extruder simultaneously with the material to be extruded so that the member is incorporated in the extrusion during extrusion, detecting the advance of the member upstream of the extrusion head, and synchronizing the operation of adjusting means operable to modify the section of the outlet orifice of the extrusion head with the advance of the member. The invention also relates to apparatus for carrying out the method. |
