an object is produced from a tubular blank of thermoplastic material of polyester or polyamide , preferably of polyethylene terephthalate by reducing the thickness of amorphous material in one or several areas of the blank by means of one or several consecutive re - shaping operations . a mechanical shaping device moves a transitional zone situated between thicker and thinner material along the blank and simultaneously elongates the blank in the moving direction of the transitional zone while reducing the thickness . after the last re - shaping operation the thinner material preferably has an oriented state . during the re - shaping operation the temperature of the material in the transitional zone is controlled at a level which , immediately before the re - shaping operation , is within or close to the range of the glass transition temperature . in one embodiment the reduction of the wall thickness of the material is begun in a track in the wall of the blank and continues symmetrically around the track . clamping devices are used to maintain the axial position of the blank . the blank is suitable for re - shaping , for instance , into a container in which the mouth also consists of oriented material .