Patent ID: 6451230
Filing Date: 2002-09-17
Classification: B29C,Y10S

Abstract:
A method for injection molding plastic molded parts from thermoplastic, comprising the following steps:producing a thermoplastic melt through the rotation of a plasticizing and injection screw in a preplasticizing cylinder; adding to the thermoplastic melt a fluid by introducing the fluid into the preplasticizing cylinder, the fluid being introduced into the preplasticizing cylinder at an axial position where the screw channels of the plasticizing and injection screw are situated at least some of the time during operation and a pressure difference between the pressure of the fluid and the pressure in the thermoplastic melt being maintained essentially constant by a controller while the fluid is being introduced into the preplasticizing cylinder; mixing the thermoplastic melt to which the fluid has been added, through the rotational motion of the plasticizing and injection screw; and injecting the mixture of thermoplastic melt and fluid into a cavity of an injection molding tool through the translational motion of the plasticizing and injection screw.