| abstract |
An apparatus for producing a tubular structure from a liquefied polymer, comprising: (a) an injection machine for injecting the liquefied polymer, (b) a first potential difference with respect to the injection machine, and a polymer shell provided thereon. And (c) increasing the local density of the polymer shell in a plurality of predetermined sub-regions of the polymer shell to alter the density in the machine direction. An apparatus comprising a mechanism for providing a tubular structure. |