| 摘要 |
<p>Hollow articles, and floating bodies in partic., are produced with internal stiffening ribs by placing a preform of plastic tubing into a blow mould and pressing outwards. The preform wall is first pressed inwards to touch at opposite sides and there weld together, when subsequently blow moulded the welds form internal stiffening ribs. The blow mould is loaded with a preform of plastic tubing and the mould tools are closed together. The mould has parts of opposite aligned heated blades which move inwards together but leave a gap which is less than the double wall thickness of the tubing, so producing welds. Short prodn. cycles, stable prod., suitable method for e.g. surf boards.</p> |
