Method and apparatus for producing plastic objects with solid sections and hollow sections

A method for producing plastic molded parts with solid regions and hollow spaces, comprising:

• blocking off a portion of a cavity of a molding tool;
• injecting plastic melt into an unblocked portion, but not a blocked-off portion, of the cavity of the molding tool along a melt flow path, which extends from a plasticizing unit through a plastic injection nozzle into the molding tool;
• injecting the plastic melt until the unblocked portion of the cavity is filled with plastic melt;
• unblocking the cavity enabling the plastic melt to reach the previously blocked-off portion of the cavity;
• simultaneously and/or subsequently to injecting the plastic melt, injecting a pressurized fluid into the melt via at least one fluid injection nozzle, so that the melt injected into the molding tool is distributed in the cavity;
• forming a hollow space in the unblocked portion of the cavity by pressing the melt against cavity walls of the molding tool;
• forming a substantially solid plastic section in the previously blocked-off portion of the cavity;
• allowing a molded part thus produced to cool down to a temperature below the melting point of the plastic melt;
• relieving the cavity of the pressure of the pressurized fluid;
• and
• demolding the molded part.