Abstract:
The present invention is concerning a manufacturing process of an object made of plastic material in a mould comprising especially a die and a punch, this process being particularly interesting in that the obtained preforms may be formed by every known method, including thermoforming, blowing, etc. The process according to the invention is characterized in that a quantity of plastics material is introduced into the cavity of the mould, in that the flow of the material is controlled while it is being introduced into the mould cavity, by displacing at least part of the punch relatively to the die, in that the punch is subjected to a restraining action while the material is being introduced, and in that the cavity is closed and the plastics material contained therein is then compressed by displacing at least part of the punch in relation to the die.
Abstract:
Apparatus for producing hollow plastic articles in a hollow die with a relatively smaller reciprocating punch therein. Plastic material is fed from a nozzle aligned with the die, into the die about the punch, the punch being initially advanced into the opening of the die and retracting as the plastic is introduced from the nozzle. When the plastic introduction is completed, then the nozzle is slid laterally on the die until the duct of the nozzle is out of registry with the die and the nozzle thus closes the die. Then the punch is advanced within the closed die to compress the plastic material into the space between the die and the punch.