Modular screw assembly
Vol. 19 #3, November 1992
Leakage between elements onto shafts in modular constructed extruder screws can cause severe turnaround problems, such as time delays or damaged equipment (screw elements) in disassembly. To minimize leakage, several steps can be taken:
a) Burrs or resident polymer on the element face inhibit good fit between them. Therefore, when reassembling screws, make sure the end faces are stoned. In particular, do the stoning in a figure eight pattern. This will help assume a "true" perpendicular face. A circular stoning pattern can more easily lead to non perpendicular end faces.
b) After screws are assembled and placed in the extruder, heat the screw configuration and then re-tighten the end bolts after thermal expansion.
- Paul Anderson
See also:
- Machinery installation
- Screw maintenance
- Technical developments
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