Yaroslavtsev

pp. 1-10

pp. 18-29

pp. 196-209

pp. 156-164

pp. 1-12

pp.15-29

The paper considers interaction and mutual influence of two external mechanical energy sources used in cutting process with the outstripping plastic deformation (OPD). One of these sources provides preliminary deformation of material while another one removes a layer of material in the сhipping form. The paper presents an approximate physical model of the mechanism of preliminary hardening of material, which acts on technological efficiency of the cutting method with OPD. It presents the standard regularities of the method efficiency, which changes depending on the load rate of preliminary deformation of material and makes physical justification that the optimum values of such load are available when machining with OPD.

The paper shows that renovation may be considered as a part of all industrial and manufacturing processes one of the objectives of which is to increase the objet resource or extend its lifecycle. It conditionally divides the renovation technologies into extension and resource renewal technologies of the object under renovation as well as into industrial and resource extension technologies at the stage of manufacturing a new product. It is stated that initial billets in renovation technologies can be not only billets damaged during operation phase. The initial billets also may be products of blank and metallurgical manufacturing, a diversity of tangible objects and materials damaged in manufacturing or lost their performances while in operation.

Cutting of thermo erosion resistant composite materials is characterized by tendency to appearance of various defects, which lead to difficulties in meeting the quality requirements for cut surfaces and products’ character reports. In Bauman MSTU experimental studies on the dimensional processing of a large group of wearproof and thermo erosion resistant composite materials produced by the methods of plasma coating, hot-pressing or plasma metallurgy were carried out; their classification by the cutting ability was proposed. Technological recommendations on the application of new processing methods of plasma coating for composites were given. 

Industrial Revolution of the 19^th century introduced the principle of division of labor into science; this fact allowed one to develop advanced scientific views which could be applied to the various technologic methods of manufacturing and assembling products along with new processing methods. However, nowadays mechanical-engineering technology requires scientific generalization. A demand arose for creation of the unified interdisciplinary technologic discipline which would allow one to develop most efficient according to various criteria manufacturing processes on a reasonable basis. This paper proposes a set of statements on the basis of generalization of practical and scientific knowledge. These theses could lay the foundation for unification of disconnected scientific views on the generation of geometry and become one of main directions for creating the unified technologic science.

Features of estimating the manufacturability during the recovery of damaged and worn-out machine components were considered in this paper. It was shown that during the recovery of machine components one has to take into account not only generally accepted and standardized manufacturability indexes but also some special criteria addressing the specificity of renovation. New manufacturability indexes were introduced; they are the coefficient of materials-output ratio during the recovery of lost material and the coefficient which allows one to take into account the amount of material removed during the recovery. Comparative analysis of the composite influence of positive and negative factors on the operating costs and resulting indexes of renovation allows one to determine the efficiency and practicability of renovation in every single case.

Calculation models of changes in heat density of an interrupted cutting process and their connection with technical and economical processing indexes were considered in this paper; these indexes allow one to determine changes in cutting tool life and in working efficiency, depending on kinematical features of the process. Manufacturing operation and kinds of work such as edge cutting, abrasive and surface plastic deformation with cyclic change of mode parameters were presented. During investigation of these operations or their development at the stage of process design it is rational to apply the specified models.

This article presents a description of a functional principle, a structural scheme and an operation of the technological photometrical equipment designed to determine the time of origin of thermal decomposition and development in polymer composite materials; this decomposition appears during machining of such materials in modes with high temperatures in the area of chip formation and represents one of the major defects of machined surfaces. The proposed equipment developed in Bauman MSTU allows to determine the value of thermal destruction during machining without harming product integrity. This equipment could be used for studying influence of machining conditions on the value of decomposition, for in-process detection and for adaptive control of machining in order to provide the required manufacturing quality.

Results of technological tests of thread cutting using thread taps and with preliminary plastic deformation of the material of the layer to be cut are presented in this article. It was experimentally established that task oriented change of physical and mechanical properties of the surface which is processed during thread cutting may lead to decrease in tension of the cutting process along with the increase in tool durability and geometrical accuracy of the thread profile. For example, thread cutting in details made of 20H13, 12H18N9T and 50RASSH steels with additional mechanical hardening provides decrease in rotational moment by 16-26% in comparison with the traditional method of thread cutting by means of thread taps; tool durability was also increased by the factor of 1,3-1,8 and in isolated cases it was possible to reduce the number of thread taps in the set and increase process efficiency.

Construction of a reamer which implements a combined cutting process with outrunning plastic deformation (OPD) during hole-making operations is considered in this article. The author provides results of an experimental investigation of efficiency of hole reaming with OPD while processing 20H13, I2H18N10T, 10H12N22Т3МR steels and L63 latten. Experience has shown that design features of a reamer appear in stabilization of the cutting process with random disturbances and eliminate vibrations in cross direction, increase homogeneity of the surface layer structure. This leads to decrease in ruggedness of the finished surface, more uniform distribution of this ruggedness over the length of a detail, increase in micro-hardness of the surface layer along with technological durability of a tool and process efficiency.

The author considers different possibilities of increasing efficiency of processing of metal chips during utilization by means of crushing them with the use of machine-tools while processing work pieces. It was shown that application cutting with outrunning plastic deformation (OPD) during the processing provides both reliable crushing of flow chips and high technological and technical-and-economic parameters of the processing. Cutting with OPD and crushing of metal chips allows to eliminate one of the most time-consuming operations of utilization –  that is granulating with the use of special equipment before briquetting and remelting. Experimental data on durability of toothed elements of crusher rolls that are used for crushing metal chips during the processing with OPD are presented. Recommendations are given on selection of a material for toothed elements and of their geometry, depending on properties of the material to be processed. It was established that application of elements made of hard alloy of VK6, VK6OM allowed them to work without regrinding for more than 20 hours.

The results of the investigation of a combined method of the final processing which is called “surface plastic deformation - smooth finish” are presented in this article. It was experimentally determined that application of this technology allows one to combine the advantages of both mechanical hardening of a work-piece surface (improving operational properties) and abrasive machining (providing high accuracy and fine finish of a surface) methods. For example, the fatigue resistance σ_-1 of samples made of 12H18N10Т and 37H12N8G8МFB steels after the proposed combined “surface plastic deformation - smooth finish” processing is increased by 28-42% in comparison with the resistance of samples processed by smooth finish only. Besides, grinding of previously deformed samples tends to be smoother than the traditional grinding at the equivalent modes. Geometrical errors of sample surfaces obtained with the use of both methods are approximately the same.

In this article the authors describe the construction and operation of a technological laboratory setup for studying the process of chip formation during cutting at micro speeds; this setup was developed at Bauman MSTU. This setup was developed on the basis of a large Zeiss engineer microscope. The setup includes a special drive for moving a work piece relative to a hard-mounted tool; it also includes an automated photo micrographic attachment for recording separate stages of deformation and destruction of a material of the layer being cut, and a specially designed dynamometric device based on the elastic and electrical operating principle for determining the cutting force components. This set of devices allows to investigate and record separate stages of the chip formation process in more detail and to estimate their influence on formation conditions and quality of machined surfaces. 

It was shown that cutting waste is a product of unique complex mixed-mode energy deposition combined in the place (the area of chip formation) and time; this deposition can be considered as special unstudied up until today transformation method of condensed medium properties. Dynamic destruction with explosion parameters combined with other physical and chemical features of the cutting process allows to assert that this processing technology of ingoing material of a work-piece may lead to creating brand new materials with a non-traditional complex of mechanical and physical properties which have their own application domains. Studying formation conditions of properties of cutting waste material would allow to find new approaches to regulation of product quality parameters during the cutting process.

It was shown in the article that any technological process can be considered as an energy conversion device. Each method, approach, means of treatment has a single-piece tool which is external energy. Performance factors are formed at the expense of both transformation and numeric distribution of external heat and maintenance of energy run-off conditions. The required output parameters of the forming process are achieved by controlling the internal processes and effects occurring in the work zone.

 Dependence of material cutability on specific work of inelastic deformation until destruction was obtained experimentally. It was shown that technological and technical economical characteristics of cutting were energetic characteristics. Application of energetic characteristic of cutability was demonstrated by the example of efficiency estimation of the combined machining method – that is, cutting with outrunning inelastic deformation (OID) for which known cutability criteria are unacceptable.

The author proposes standard solutions for choosing a rational technology of dimensional processing of constructions made of composite materials – these solutions are based on researches conducted at BMSTU and on their practical application. It was shown that development of new processing techniques and special equipment, purposeful creation of the required energetic state of work material, application of combined energy deposition are promising directions to improvement of the cutting process which ensure high quality and economical performance of the product at the stage of dimensional processing.

The authors propose a generalized structural diagram of technological renovation processes of machine elements, based on the characteristic of transformation vicissitude of entry shell properties. The authors show the ways to provide the quality of renewable products, basing on the analysis of interrelation between the structural diagram elements, considering technological inheritance of renewable product properties. The concept “the inheritance of life cycle” was introduced and described.

Basic positions of methodology of creation of high-effective technologies and research of new methods of treatment were considered. Systematization of ways to improve the machining, built on the basis of generalization of experience of the solutions of technological industrial problems and scientific achievements in the field of the cutting theory was brought. By the example of machining, the effectiveness of practical use of this methodology was shown.

The author shows comparability of dynamic characteristics of cutting processes and tests of materials in high dynamic pressures environment. Possibilities and advantages of using the cutting method as a new method of studying physical-mechanical properties of materials were considered at high-speed deformation and destruction.

It is shown that in-cut contact interaction of an instrument and a raw part is interaction of fields at the atom-molecule level. The article tells about processes and phenomena accompanying the cutting process on the nanolevel: mechanical, thermal, thermoelectric, electromagnetic, structural changes of material. New spheres of technique and technology of cutting are indicated.

Mechanism of influence of metals surface strain hardening to chip disposal process has been studied. It has been clarified that the form changing process evolution while two continuous stages of deformation in cutting of mechanical hardened materials satisfy the condition of linear addition of deformation specific works in accordance with unite flow curve σ_i - ε_i, which can be appreciated as a theoretical base of mechanics of cutting process for deformed metals with non-uniform in depth mechanical properties. Theoretical relationships have been derived for estimation of main component of chip disposal force. Figs. 5.

It is shown that cutting is an explosion modification, and the data confirming this statement are given. New concepts of deforming and destruction at cutting are presented; a combined physical-technological model of the process of chip formation and formation of surface layer quality is elaborated. A new version of classical "σ_i–ε_i" diagram, namely, diagram of large deformations for dynamic destruction is proposed. A common mechanism of formation at metal cutting of chip of any type is theoretically substantiated. It is shown that physics of high dynamic pressures can serve as a research basis for machining by cutting. Figs. 2. Tabs. 3.