REDUCING THE LABOR INTENSITY OF HOLE MACHINING BY INCREASING THE ACCURACY OF COUNTERSINKING OPERATIONS WITH PRECAST TOOLS
Problem statement (relevance of the research). When machining high-precision parts, mechanical engineers face a long adjustment of the technological process after its design and diagnosis of the causes of defects. Machining of precise and deep holes creates special difficulties for process engineers, when designing technological processes. But, despite the effort expended, after adjusting the technological system, it is not possible to avoid the frequent occurrence of defects in machining accuracy. It takes a long time to diagnose the causes of defects. Analysis of the technology of machining precise and deep holes at modern enterprises has shown that the main reason for long-time machining is the difficulty of assigning technological parameters of operations and transitions at the initial machining stages, which include drilling and countersinking. The assigned machining parameters, such as cutting modes, geometry of the cutting tool, for these operations slightly meet the requirements for the accuracy of the axis location, but rather meet the requirements for the accuracy of the diameter, as well as the requirements of the highest output and durability of the tool. It is possible to improve the quality of forecasts for the hole machining accuracy by designing mathematical models of hole shaping and computer models for calculating accuracy, taking into account the features of countersinks with polyhedral disposable plates. The methods used. In this study, the authors used methods of mathematical modeling, cutting theory, as well as the main provisions of the theory of mechanisms and machines. Novelty. The authors have developed a mathematical model to calculate the drill run-off, when machining with the countersink with polyhedral disposable plates, factoring into new variables: the axial displacement of the vertices of the cutting edges of polyhedral disposable plates τ from each other and the difference in the main cutting edge angles φ, which were not previously used in existing similar mathematical models. Result. The developed mathematical model predicts the drill run-off, when machining with a countersink with polyhedral disposable plates, varying the cutting modes, thereby reducing the labor intensity of hole machining. Practical significance. The authors have developed a technique used to select operation parameters, providing the set accuracy, when machining with countersinks with polyhedral disposable plates. This contributes to an increase in economic and technological efficiency, when machining holes with a countersink with polyhedral disposable plates, using the developed mathematical model based on reducing the number of transitions and increasing the ability to aggregate operations.