| 摘要 |
A cable is made with a sheath of extruded plastics material. During manufacture it is desirable to cool the sheath as rapidly as possible without damaging the sheath by imposing too great a temperature gradient thereon. To this end the sheath is cyclically cooled (e.g. in troughs of water) until there is a danger of damage and then reheated to relieve the build up of stress and then recooled and so on. At least the first reheating step is performed with a fluid of low thermal conductivity (e.g. air), preferably at a temperature above the softening temperature of the plastics material. |
