Guzenko D. Improvement of the efficiency of rough machining with stepped cutters on heavy lathes

The thesis is dedicated to the improvement of the efficiency of rough machining process with stepped cutters on heavy lathes. The analysis of literary sources in the field of rough machining with large cutting areas under conditions of heavy engineering has been done. The failures structure of sectional cutters during rough turning with large allowances and crust was analyzed on lathes. It is established that the main failure reason of the cutters is breakage and uneven wearout of the cutting plates. The disadvantage of sectional cutter design is their poor performance due to insufficient strength of the cutting plates because of ineffective attachment of the cutting plate to the tool body. A new scheme of step–by–step cutting with sectional cutters and advanced nodes for mounting special cutting plates with a ledge with the help of an adhesive has been developed. A technique for the analysis of the stress–strain state of the sectional stepped cutters for rough machining by the finite element method was developed. A technique for investigating dynamic characteristics of a technological system has been developed. It allows to consider a stepped sectional cutter as a sectional multi–mass structure and, by simulating the oscillation process, to predict the failure of a tool depending on the combination of amplitude and frequency. Experimental studies of the variations of combined cutters allowed to establish the trueness of the proposed methodology and of the model. On the basis of theoretical and experimental researches an advanced design of a stepped sectional cutter for rough machining with large cutting areas on heavy lathes has been developed. An algorithm and a program–methodological complex of multicriteria optimization were developed, that allows to solve the problem of choosing effective cutting modes for a new step–by–step cutting scheme during rough machining with sectional cutters on heavy lathes.