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scientific edition of Bauman MSTU

SCIENCE & EDUCATION

Bauman Moscow State Technical University.   El № FS 77 - 48211.   ISSN 1994-0408

Machine Building and Engineering Science

Investigation of sensitivity of MIG/MAG welding of a root weld to geometrical disturbances of the groove assembly
# 10, October 2013
DOI: 10.7463/1013.0631684
A.V. Maloletkov, M.V. Shvarc
This article provides a comparative analysis of requirements for groove pre-operation before automatic welding. It was mentioned that the required accuracy of edge pre-operation could hardly be achieved under field conditions. A review of modern methods of welding adaptation was provided. Influence of groove geometry disturbances on formation of a root weld in the process of automatic MIG/MAG welding was investigated through a set of experiments. It was determined that critical values of a root gap and misalignment disturbances depended on the mean root face value. Recommendations on accuracy of assembling and edge machining were provided.
Manufacturability of renovation objects during the recovery
# 1, November 2003
DOI: 10.7463/1103.0628299
V.M. Yaroslavtsev
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.
Basic concepts of the similarity of processing methods
# 2, December 2003
DOI: 10.7463/1203.0628312
V.M. Yaroslavtsev
Industrial Revolution of the 19th 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.
Technological aspects of dimensional processing of products and coats made of thermo erosion resistant composite materials
# 1, January 2004
DOI: 10.7463/0104.0628312
V.M. Yaroslavtsev
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. 
Application of laser tracking system in automatic MIG/MAG welding control
# 09, September 2013
DOI: 10.7463/1213.0628186
M.V. Shvarc, A.V. Maloletkov, R.A. Perkovskii
The paper proves a use of tracking systems for real-time control of automatic and robotic MIG/MAG welding. The basics of modern tracking systems based on the optical triangulation were provided. A review of recent applications of such systems in welding manufacturing was also presented. An adjustment algorithm, operation in the scanning mode and data logging were illustrated by the example of SLS050 («Meta Vision Systems» Ltd.) tracking system application. Critical analysis of the system was carried out. Pros and cons, application domains and requirements for the welding equipment to be used were determined. This paper also emphasizes further approaches to integration of SLS050 with automatic pipeline welding equipment.
Estimation of the stress-strain state of work pieces affected by cavitational-abrasive wear
# 12, December 2013
DOI: 10.7463/1213.0623531
L.A. Tischenko, A.A. Kovalev, V.D. Shashurin
This article presents the results of quantitative assessment of process parameters which occur in materials of work pieces susceptible to cavitational-abrasive wear when in operation in aggressive fluid media. The authors propose a new algorithm for estimating the stress-strain state of materials of technical system’s elements affected by abrasive particles and micro water jets resulting from collapse of cavity pockets. Several hypotheses were introduced for describing this physical phenomenon; they were justified in this work. On the basis of the proposed algorithm evaluation calculations of existent parameters which allow one to make conclusions on the stress-strain state of several materials were performed. The obtained results were presented in the form of functional dependences.
Simulation of a cavitation attack on the working surface of a work-piece operated in a hydro-dynamic medium
# 11, November 2013
DOI: 10.7463/1113.0623525
A.A. Kovalev
This article justifies the necessity of developing a general mathematical model of cavitation wear of work-pieces, which takes into account design-engineering features and operating modes along with properties of external hydro-dynamic environment and the strain-stress state of a work-piece. Simulation results of the strain-stress state of a work-piece operated in a hydro-dynamic medium and influenced by cavitation were presented in this paper along with pressure values, the equivalent stress and deformation velocity in the work-piece’s materials under consideration. The developed evaluation model for the strain-stress state of a work-piece is one of the basic modules of a general mathematical model of work-piece cavitation wear.
Deterioration of nozzle extension in manufacturing systems of hydro-abrasive treatment
# 11, November 2013
DOI: 10.7463/1113.0623516
L.A. Tischenko
This work justifies the necessity of developing a method of quantitative estimation of nozzle extension deterioration of water jet cutting equipment during continuous operation under given manufacturing modes. The proposed method consists of several major blocks; their function is forming various mathematical models which describe wearing processes. Simulation results of a hydro-abrasive jet in a nozzle extension were considered in this work along with interaction between abrasive particles and channel walls. Influence of the nozzle extension wear on the erosion rate of the processed material was also investigated. 
A profilometry of the preparation of a joint for solving problems of geometrical and technological adaptation of welding equipment used in the automated methods of arc welding of tubes
# 09, September 2013
DOI: 10.7463/0913.0618953
E.A. Gladkov, Yu.O. Toloknov, P.S. Demidov
Effective methods of geometric adaptation of the welding equipment to anomalies in the geometry of the joint assembly in arc welding by applying servo system were proposed. The anomalies in the joint geometry of the assembly were described and their impact on the quality of welds was evaluated. The variant of a use of optical sensors based on the CCD sensor for the measurement of the profile geometry and spatial arrangement of the joint was also proposed in this paper. Technical solutions for protection of the optical sensor from heat and light effects produced by the welding arc were described. Principles of the correction of technological parameters depending on the geometry of profile anomalies and the spatial arrangement of a joint were described.
Development of a model of ultra-jet instant diagnosis of materials
# 10, October 2013
DOI: 10.7463/1013.0604128
A.A. Kovalev, L.A. Tischenko, F.A. Savenkov
This article deals with application of ultra-jet diagnosis of materials, which is one of the most promising and complex methods allowing one to estimate durability of materials instantly under various conditions. A review of existent mathematical models which allow one to evaluate the depth of a honeycomb originated on the surface of a material as a result of ultra-jet influence. Requirements to the ultra-jet interaction model and the material being diagnosed were determined. On the basis of these requirements a model which could be used in the technique of the ultra-jet instant diagnosis was proposed.
Thread cutting using thread taps and with preliminary plastic deformation of the material of the layer to be cut
# 08, August 2013
DOI: 10.7463/0813.0570897
V.M. Yaroslavtsev
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.
Micro-arc oxidizing methods for surfaces of details made of titanium alloys
# 07, July 2013
DOI: 10.7463/0713.0583316
V.K. Shatalov, L.V. Lysenko, A.N. Minaev, O.V. Sulina, A.O. Shtokal
Use of titanium alloys in marine environment imposes high requirements on the material quality of contacting parts. Micro-arc oxidation (MAO) is a widely used technique for forming a stable oxide layer with anti-scoring protection. Electrochemical techniques may be difficult to implement for treatment of large size structures, since they require large capacity electrolytic baths as well as high power current sources. Untraditional technical approaches are sought for forming a localized oxide layer on large size structures. This paper describes micro-arc oxidation techniques and equipment which simplify the oxidation bench design, reduce its overall dimensions and electrolyte consumption, as well as electric energy consumption, providing quality anode coating on large nomenclature of titanium alloy parts. The specified problem is tackled due to use of devices that provide local oxidation and are moved along the whole surface of a detail or just along necessary areas. This fact leads to a significant reduction in required power of current sources because MAO occurs in a small area. It also simplifies the cooling process.
Calculated parameters of a draw band twisted joint
# 07, July 2013
DOI: 10.7463/0713.0582853
V.G. Kovalev, E.A. Skorohodov
In this article for the first time the authors consider a method of determination of basic parameters of electrical-installation binding by wire wrapping which ensures higher reliability and durability compared with soldered joints. The method is based on a use of physical processes occurring during this kind of installation. The results of the analysis allowed to determine the basic parameter – that is the radius of the wrapping roller’s working end. Experimental data on the value of the deformation degree of a real wrapping wire were used to estimate the study result. The obtained results can be used to calculate a wrapping tool.
Comparison of static characteristics of electro-hydraulic amplifiers with proportional and servo control
# 07, July 2013
DOI: 10.7463/0713.0579738
M.I. Salman, N.G. Sosnovskii
The authors consider results of experimental studies of static characteristics of amplifiers with proportional and servo valve control. A comparison of characteristics that were recorded in a specially created complex allows to evaluate the accuracy of an amplifier with a proportional valve control and determine the impact of hydrodynamic forces applied to the spool on these characteristics. Experimental results prove flow characteristics and dependence of hydrodynamic forces on displacement of the spool; these results were obtained with the use of a computer model of a hydraulic amplifier. It was shown that if the spool has profiled surface, static characteristics of amplifiers with a proportional and servo valve control become approximately the same due to the balance of hydrodynamic forces. Thus, the authors established a possibility of application of simpler amplifiers with less power consumption and with a proportional valve control instead of a servo one. This statement is important for designing hydraulic drives.
Stress-strain state in a combined operation of expansion and swaging when manufacturing adapters
# 08, August 2013
DOI: 10.7463/0813.0578962
A.A. Solaiman, I.N. Shubin
The authors consider a combination of two operations (expansion and swaging) in one manufacturing step. A coordinated solution to equilibrium equations, plastic conditions, relations between stresses and strains were used during the analysis of these operations.  As a result, data were obtained for calculation of effective stresses and strains for both zones - swaging and expansion. The results of the study and calculation of the friction effect on the magnitude of stress and strain state in the combined operation are given in this work. Methods of controlling the formation process were defined. A numerical experiment was carried out with the use of MATCAD by varying the main parameters of the process which are friction and strain.
Materials for an abrasive tool. Review
# 07, July 2013
DOI: 10.7463/0713.0577449
A.I. Ovchinnikov
This author analyzes recent significant changes in the normative-technical documents in reference to grinding materials, determination of their properties, quality control and designation.The article also presents information on new classification of grain composition, bonding materials, hardness and structure of abrasive tools. Application domains were specified for different grades and parameters of grinding materials, along with their correspondence to foreign analogues. Particular attention was paid to super-hard abrasive materials based on diamond and cubic boron nitride (CBN), identifiers of their parameters as well as rational application domains in manufacturing engineering. The author also considers flexible abrasive tools. There are examples of designation of materials for abrasive tools and their individual parameters.
Inertial method for estimating the effect of lubricants’ quality on energy efficiency of chain transmissions
# 06, June 2013
DOI: 10.7463/0613.0577582
A.V. Egorov, K.E. Kozlov
The article presents a methodology, theoretical justification and experimental results of testing the inertial method for estimating the effect of lubricants’ quality on energy efficiency of chain transmission as part of a chain drive. The proposed method allows to investigate mechanical losses in chain drives within a wide range of speed, load and transient modes, which directly depend on lubricants’ quality. Equipping the drive with hardware and a software system, it is possible to estimate the effect of lubricants’ quality for the inertia moment of losses in a chain transmission during operation of a chain drive.
Simulation of forming process of discrete-slot structure in case of bi-rotatory edge cutting machining
# 07, July 2013
DOI: 10.7463/0713.0576656
D.V. Ivanov
Creation of bi-rotatory machines of multiblade processing and development of methods for their exploitation is an actual scientific-technical task closely connected with the problem of creation of high-technology and high-performance equipment. Development and efficient exploitation of a bi-rotatory complex for processing details with a discrete-slot surface structure which implement its technological capabilities require knowledge of the regularities of formation of details. In this case it is necessary to solve a number of problems associated with the modeling and analysis of the formation process of this kind of structure, which haven’t been solved yet. The aim of this research is an identification and functional interrelation analysis of geometrical parameters of a curvilinear slot with geometric and kinematic parameters of a bi-rotatory cut-map. Functional relations for determination of geometrical parameters of the obtained discrete-slot structure were developed. Vector formalization of configuration of a technological gearing scheme was introduced basing on the concept of cycloidal forming. The generalize vector model of cycloidal forming which is universal for external, internal and encircle technological gearing schemes of the couple (detail-tool), for milling, tangential turning, climb cutting and counter cutting, was developed. A solution method for the model of a cycloidal slot forming based on the transcendence formula reduction to algebraic form, which allows one to calculate a slot length to a precision of 0.03 in defined technological gearing scheme and kinematic processing parameters, was also developed; in the tasks of a parametric synthesis it allows one to determine parameters of a cut-map in order to obtain the required slot length.
Prediction of loss of accuracy in machine tools
# 05, May 2013
DOI: 10.7463/0513.0574593
V.M. Utenkov
This author considers development of techniques for predicting loss of accuracy in machine tools with guideway wear. The problem of obtaining sufficient accuracy for practical estimation of the resource mean value and its possible dispersion was described. The Monte Carlo method, which is currently used for solving this problem, was investigated; its main disadvantages were listed. A basic description of the main stages of the new method for predicting loss of accuracy in machine tools in case of guideway wear was presented with an example of realization of these stages. The author also presents results of predicting loss of accuracy for 16K20F3 and STP-220AP machine tools, which were obtained after cycles of static simulation of wearing process of guideways in case of sufficiently accurate determination of distribution density of resource probability over accuracy parameters.
Mathematical modeling of machine tools’ guideway wear
# 04, April 2013
DOI: 10.7463/0413.0574580
V.M. Utenkov
This article is devoted to the development of methods of mathematical simulation techniques for modeling machine tools’ guideway wear. An example of calculation of pressure curves in the edges of the machine tool’s guideways was presented; values of pressure were determined according to the scheme of the forces and reactions. The fundamentals of method for calculating wear of guideway friction pairs developed by prof. A.S. Pronikovd were considered. Possibility of improving the method was demonstrated for the case, when greater accuracy for modeling wear process is required. Algorithm of wear simulation with the possibility of calculating guideways wear with any complexity of changes in pressure curves along the trajectory of working body on the bedplate. The only requirement for the calculation is that the pressure curve remains constant at the elementary step of modeling. Experimental data which verify the accuracy of modeling by the example of study of the wear process of guideways and changes in the trajectory of the movable working body of machine tools under operating conditions were also presented in this article.
 
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