Flight undercuts

A sled device for measuring the depth of screw channels, barrier flight undercuts, and mixer flight undercuts is shown in Fig. 10.1. To use this device, the sled is positioned on the top of the screw with the micrometer tip contacting the top of the flight. The micrometer is zeroed at this position. Next the sled is slid axially on the screw, and the micrometer is adjusted until the top of the micrometer probe contacts... 

Figure 14.8 Schematic of an ET section a) the section is used in place of a metering section, and it has two channels labeled A and B. The unfilled flight in the ET section is undercut with respect to the filled flight, b) cross-sectional view perpendicular to the flight tips showing the two channels and a flight undercut between them. The arrows show the direction of the flows perpendicular to the flight (courtesy of Jeff A. Myers of Robert Barr, Inc.)...

Figure 14.22 Schematics for Stratablend mixing sections a) Stratablend schematic, b) Stratablend II schematic, and c) cross-sectional view perpendicular to the flight tips showing the three small channels or grooves and the flight undercuts between them (courtesy of Timothy W. Womer of Xaloy Incorporated)...

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