Patent ID: 7014353

Claim:
An apparatus for plasticating material comprising: a barrel having a longitudinal axis, along which material moves axially from an inlet to an outlet; a rotatable screw disposed within and cooperating with an inner wall of said barrel, including an axial core and a metering section; a main flight arranged helically on, and extending radially from the core in the metering section, the main flight having a first outer periphery facing the barrel, a thickness and multiple, mutually spaced cut-through recesses extending through the thickness at the first periphery, the cut-through recesses providing a passageway for the material to cross the main flight; a secondary flight arranged helically on, and extending radially from the core, located between successive helical passes of the main flight in the metering section having a pitch substantially equal to the pitch of the main flight, the secondary flight including a second periphery facing the barrel and spaced radially from the barrel a greater distance than the first periphery is spaced radially from the barrel, thereby providing a passageway for the material to cross over the secondary flight; and wherein the axial core of the metering section is undulating having a plurality of crests and valleys in a helical pass of the main flight about the axis, separated by the secondary flight, a height of the crests and a depth of the valleys varying angularly about the axis, each crest having a maximum height at a point next to a maximum depth of the separated valley.