Manufacturing and Production

Extrusion of Pipe, Profile and Sheet

An extrusion line makes a continuous product, which means a fault is not one rejected part but metres of scrap produced while somebody works out what changed. This course concentrates on holding the line steady. Delegates work through screw design, compression ratio and the melting behaviour a given polymer needs. Barrel temperature profiles and their effect on melt quality follow. Die design and flow balance are covered, including the die swell and draw down that decide final dimensions. Calibration and cooling are addressed for pipe, where vacuum tank and sizing sleeve control wall thickness and ovality. Profile and sheet lines follow with their own take off and cooling arrangements. Haul off, cutting and coiling are covered. Dimensional control is treated as continuous measurement rather than end of run inspection. Common defects are diagnosed: surging, melt fracture, gels, wall variation and internal stress. The course closes on start up, purging and changeover losses.