| 摘要 |
<p>Method and devices for manufacturing biaxially oriented tubing from thermoplastic material. The method comprises forcing the tube over a mandrel (4) at an orientation temperature of the plastic material, which mandrel (4) comprises an expansion part (6) which produces expansion in the circumferential direction of the tube. The forcing over the mandrel is achieved by exerting a pushing force on the tube upstream of the expansion part of the mandrel by means of pushing means (12) acting upon the outside of the tube, and by exerting a pulling force on the tube downstream of the mandrel. The pushing means (12) act upon the tube at a distance upstream of the mandrel, and the tube is supported between the place where said pushing means act and the expansion part of the mandrel.</p> |
