In present-day economic conditions, extrusion is one of the advanced feedstuffs and food production processes involving intensive manifold heat and force action. During extrusion, the main function is performed by a compression mechanism which includes a forcing screw unit built into the cylinder (cowling). The forcing mechanism performs the task of transferring material while concurrently compressing it up to a required pressure and increasing the material’s temperature due to compression and friction against the cowling's sides. In our view, the first technique is appropriate when a material which is moving within the compression area is in viscous-flow state. The second technique is optimal for theoretical description of areas of loading, transportation, and compression (melting) where the working pressure is maintained.