Blow molding process and apparatus

An improved process and apparatus for blow molding of engineering plastic materials, using a mold and an injection machine with a die for producing a hollow plastic parison to be partially received in the mold, is characterized in that an injecting operation and a preblowing operation with air from the die into the parison are concurrently commenced at a high injection speed and a low air pressure, with a material remaining in the die (10) being integrated with an upstream portion of a preceding parison prepared in a preceding blow molding run, to complete an instant parison. The upstream portion has a closed and free lower end prepared in the preceding run. The apparatus is provided with a pinching and cutting (30) device for self-adhering and separating the completed parison (1) above and in the vicinity of the mold (50) to prepare the above mentioned closed free end. In an embodiment, a heater is provided to heat the upstream parison portion immediately after the parison is separated into the upstream portion closed at the free lower end and a downstream portion to be received in the mold for blow molding and until immediately before a next injection.