The paper describes the development of practical methodology for constructing the systems of monitoring the technological processes execution in digital machinery production. The methodology is primarily designed for controlling the machining technological processes in the metal-cutting workshop. In order to implement the system of monitoring the execution of technological processes in low-volume/ high-variety production the paper sets the tasks of defining the initial system condition, identifying the most significant factors, evaluating the probability of completing technological operations, modeling the flow of each technological process in the workshop. The paper also justifies the applicability of the expert evaluation method, the Pareto method, and neural network usage for developing the system. A flow chart of the simulation modeling of monitoring the technological process implementation is suggested; the chart demonstrates the interrelation between the methods of analyzing the technological processes described in the paper. Basing on the simulation modeling results it is possible to draw the conclusion that all technological processes will be completed during the work shift and also to identify the possible causes of failures before the production cycle is complete.