Thermoplastic forming process

摘要

Method and apparatus for stretch-forming a hollow article from a sheet of thermoplastic material at a temperature higher than 25 DEG C. below the melting point wherein a stretching tool having at least one tip at a temperature lower than 50 DEG C. below the melting point is pressed against the sheet, and the initially stretched sheet is then further stretched and simultaneously dilated. One form of tool comprises a number of blades arranged around a plunger which are moved forward and outwardly after initially stretching the sheet forwardly. The articles so produced can be further formed by blow moulding.