| 摘要 |
The invention relates to a method for temperature conditioning a blank (10) of plastic material, a conditioning mandrel (20) being placed within the blank (10) and thereafter expanded to reliable abutment against the inner surface of the blank. The mandrel is thereafter displaced back to its starting position. The outer surface of the mandrel is adjusted to and maintained at a certain temperature, whereby, during the abutment, an energy exchange takes place between the blank and the mandrel for adjusting the material temperature of the blank. At high temperatures of the mandrel, the mandrel is displaced out of the blank after such short time that the plastic material in the region of the abutment surface never passes the critical temperature at which tacking between the plastic material and/or thermal crystallization of the plastic material occurs to any appreciable degree. As a rule, this process is repeated one or more times. In an apparatus according to the invention, the dimensions of the conditioning mandrel (20) and the blank (10) are adapted to one another such that, in the position within the blank, the outer surface of the conditioning mandrel abuts, after expansion, against the inner surface of the blank. Control and regulation means are provided for abutment of the conditioning mandrel against the inner surface of the blank during an adjustable time interval. |
