Extruder line

Tolerance The penalty for having an unbalanced wall is the reduction of tolerance control. Tolerance limits are usually at least doubled. Also, with certain plastics it is more difficult to process them, such as those with low melt strength. Although the balanced wall is the ideal, having it is not always possible. Recognize that the unbalanced wall can be extruded with proper die design and control of the extruder line from upstream to downstream equipment. 

Examples of products and a twin-screw extruder line for the manufacture of hard metal mixtures are shown in Figs. 14.19 and 14.20. The raw materials are supplied to the extruder as a pre-mix, plasticized and homogenized. If necessary, excess air can be removed by vacuum degassing. 

Figure 5.1 5 Coating extruder line highlights the hot melt contacting the substrate just prior to entry into the nip of the pressure-chill rolls...

For the manufacturing of injection-moldable natural fiber/PP-compounds, the band of the fiber is impregnated by the PP-melt in a continuously running extruder line. The natural fiber reinforced compound is granulated at the extruder exit. Melt compoimding of short-cut fibers has not proved viable because of metering problems with the natural fibers. 

Each of the processes (blown film, sheet, tube, etc.) contains secondary equipment applicable to their specific product lines such as computerized fluid chillers and temperature control systems. Equipment has become more energy-efficient, reliable, and cost-effective. The application of microprocessor and computer compatible controls that can communicate within the extruder line results in the more accurate control of the line. 

The MVX has been used to make hoses with a cross-head, and sheet material with a roller die head. This method is economical when the whole of the output of the MVX can be used. If, for example, small extruder lines with an output of 50-200 kg/h are to be used, then direct compounding would be difficult to justify. But for 400-3 000 kg/h direct compound and product production has proved to be very profitable. 

This work had two aspects. In the first one, the interaction between CO2 and nylon-6,6 melt is explored by investigating by the effects of CO2 on nylon-6,6 shear viscosity and hydrogen bonding. In the second one, an attempt is made to establish feasible conditions for spinning of nylon-6,6/C02 mixtures, to produce nylon filaments. Extrusion and spinning experiments of nylon-6,6 / CO2 were conducted on a twin- screw extruder line and the effects of carbon dioxide on viscosity and spun filaments morphology and tensile properties were investigated. 

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