The paper considers the problem of accuracy assurance during part manufacturing. Ensuring the required accuracy is one of the aspects of achieving the level of quality, implied during product design. It should start even before the actual manufacturing process, during process planning, which is one of the main stages in product life-cycle. In digital manufacturing, while using automatic and semi-automatic equipment, including CNC machines, a multi-operational technological process must be reliable in the context of ensuring its accuracy parameters, i.e. must guarantee in advance the compliance with requirements of dimensional accuracy and surfaces location and orientation which is specified in a part drawing. This can be achieved by carrying out a dimensional accuracy analysis of a technological process at its design stage, which will reduce time and material costs when introduced in production, due to a significant decrease in the probability of obtaining defects, related to precision parameters. When conducting a dimensional accuracy analysis of a technological process, it is necessary to preliminarily create diagrams of linear dimensions and circular runouts. Creating these diagrams and performing the required calculations manually is a rather time-consuming process. This fact as well as the lack of necessary software packages (even though there exist several programs for calculating linear and diametric dimensions and machining allowances, developed by authors of the present paper) today at industrial enterprises engineers do not conduct dimensional accuracy analysis when designing multi-operational manufacturing processes and rely solely on their own experience and the experience of adjusters and CNC machine operators. And this, in turn, holds back the process of manufacturing process automation, which is unacceptable during the transition to digital manufacturing. As a solution to this problem, it is proposed to introduce into the practice of technological process design developed calculation programs and a software tool in development, based on methods of interactive synthesis of linear dimensional and runout diagrams, described in the paper.