“…In the case without a propeller, three of the effects are statistically significant. After eliminating the nonsignificant effects, the following adequate equation was obtained for the change in sectional expansion index when extruding without a propeller: SEI1 = -42,891 + 0,371.Nf + 0,014.Nw -0,204.W (7) In the case with a propeller, three of the effects are statistically significant. After eliminating the nonsignificant effects, the following adequate equation was obtained for the change in sectional expansion index: SEI2 = 50,038 + 0,038.Nw -2,302.W -0,373.Tm -0,008.Nw.W + 0,021.W.Tm (8) The increase in the working screw speed in combination with low moisture content of the raw material leads to an increase in the sectional expansion index (Fig.…”