The paper presents the results of studies on the justification of a rational program for running-in of tribosystems. It is shown that the first component of the program is the fulfillment of the condition on the verge of loss of stability due to the appearance of accelerated wear, with the maximum load on the tribosystem and the minimum sliding speed. This mode performs the function of "training" the surface layers for future operating conditions due to deformation processes and changes in the roughness of the friction surfaces. The mode is characterized by minimum wear rate values and maximum friction coefficient values.
The second component of the running-in program is the fulfillment of the condition on the verge of loss of stability due to the appearance of burrs on the friction surfaces, with minimal load on the tribosystem and maximum sliding speed. This mode performs the function of "adaptation" of the surface layers to the future operating conditions by increasing the rate of deformation of the materials of the surface layers on the spots of actual contact. The mode is characterized by maximum wear rate values and minimum friction coefficient values.
The third mode of the program aims to form surface structures and roughness on the friction surfaces of tribosystems that correspond to operational modes. This mode performs the function of "sufficient adaptation" of the surface layers to the future operating conditions, and corresponds to the condition with the maximum value of the stability margin. The final result of the running-in process is the transition of the tribosystem from an unbalanced, thermodynamically unstable state to a stationary, equilibrium state, as a result of which such parameters as wear rate, friction coefficient, temperature and roughness of the friction surfaces are stabilized. Such a step-by-step transition is associated with the formation of a special, dissipative structure of the surface layers of triboelements as a result of self-organization.
The use of the three-mode program will reduce the time for tribosystems to run in by 23.0 - 38.4% compared to other programs. The effectiveness of the developed three-mode program is proven by experimental studies with the calculation of the modeling error.