Distributive Melt Mixing Screws

Distributive melt mixing (DM2) screws from Glycon Corporation are based on the ET screw patent and thus are constructed as described by Section 14.2.2 and as shown in Eig. 14.8. Variations in the entry and exit sections occur, however, between ET and DM2 designs. Like the ET screw, the DM2 screw is capable of operating at high rates and low discharge temperatures [34]. 

A mixing experiment was performed using a 63.5 mm diameter DM2 screw as outlined in Section 8.4.1. The DM2 main screw was 18.5 diameters long and was fitted with a 2.5 diameter long removable tip. The main section of the screw had a 

Screw Maximum Operating Screw Speed, rpm Continuous Rate, kg/h Time to Piasticate 0.5 kg,s 

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Spalding, M. A., Kuhman, J. A., Larson, D., Kuhman, J., and Prettyman, H. L., Performance of a Distributive Melt Mixing Screw with an Advanced Mixing Tip, SPE ANTEC Tech. Papers, 50, 599 (2004)... 

The polymer melt has to be well mixed when it leaves the extruder screw and enters into the die. For this reason it is beneficial to have an efficient distributive mixing device at the very end of the screw. Mixing was discussed in detail in Section 7.7 and mixing devices and mixing screws in Section 8.7. 

Pinto, G. and Tadmor, Z., Mixing and Residence Time Distribution in Melt Screw Extruders, Polym. Eng. Set, 10, 279 (1970)... 

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