A process for dry milling wheat grains in a six-roller mill used in chem. and food industries was studied in air to det. the relationships of productive traffic, states and changes in the motion of grainy particles, their displacement, mixing, and grinding. Some granulometric indicators of a product quality (estimators of prepn. and dough fermentation) were used in the evaluation. The operation efficiency depended on friction conditions, collisions, cutting, and the mill design features. A good disintegration of the wheat grains (0.67 mm) was achieved at low energy consumption (72.3-123.3 J/g) and high yield (32.1-56.2 kg/h).