Abstract
The relationship for the calculus of flow in a single screw extruder was inferred based on the analysis of the real movement of the powder material in the feeding zone, considering the screw rotating and the barrel stationary. The relationship is applicable to extruders with the barrel in the feeding zone both smooth and grooved. Both the slipping of the powder material with respect to the surface of the screw and the existence of a velocity profile on the depth of the powder layer were taken into consideration when establishing the flow relationship. The fundamental hypotheses of the new theory are: - barrel stationary and screw rotating; - in the powder layer, powder particles have a relative motion. The relationship for the direct calculus of the deviation angle b was deduced. From the analysis of the results obtained applying the relationship for flow, where the flow factor can be calculated with the relationships in the paper, one would notice that the flow will grow both with increasing the depth of the channel in the feeding zone and the increase of the friction coefficient between the powder material and barrel,, as well as the one between the powder material and screw. Keywords: extrusion, optimization, flow factor, deviation angle