Optimization Of Technological Processes Research Articles

The influence of hardening medium in the vacuum carburizing process on the distortion of machine elements used in the automotive industry

Purpose: As part of this study, the influence of the hardening medium on distortions of FineCarb® carburized rollers used in the automotive industry as elements of fuel pumps has been examined. The analysis was carried out for the process of quenching in gas at different pressure of cooling gas and quenching in oil at variable delay time of oil mixers. Design/methodology/approach: The research was carried out on real elements used in the automotive industry as elements of fuel pumps. FineCarb® vacuum carburizing technology was used in order to obtain optimal parameters of the surface layers. During quenching a variable related to the parameters of the quenching medium was introduced. For quenching in gas it was the pressure at which nitrogen was introduced into the cooling chamber, while for quenching in oil it was the time of mixers delay. The sample batch was laid out in accordance with the PPAP (Production Part Approval Process) requirements for the automotive industry. Microhardness and radial runout measurements were carried out on the samples and subjected to statistical analysis. Findings: The analysis of each hardening processes has showed that depending on the cooling medium used, different distortion values are obtained. The distortion value is significantly influenced by the parameters of the hardening process – gas pressure/oil mixers delay. With the proposed quenching parameters, there is no relationship between the location of the sample in the furnace chamber and the distortion value. The smallest hardening distortions were obtained as a result of the hardening process in gas at a gas pressure of 3 bar. Hardening in gas was characterized by the smallest scatter values of obtained results of radial runout. Research limitations/implications: Basing on the studies and analyses carried out in this work, it can be concluded that the introduction of gas quenching technology instead of oil quenching technology is justified qualitatively and economically alike. Hardening in gas was also characterized by the smallest scatter values of obtained results of radial runout. This is an extremely important technological and economic aspect, due to the cost of grinding processing. Practical implications: The automotive and aviation industries are putting ever greater demands on the quality of manufactured components while reducing costs. Volume 94 • Issues 1-2 • May-June 2019 It requires optimization of technological processes from co-operators. In the case of hardening plants, the most important aspect is obtaining repeatable, precisely planned parameters of the carburized layer, as well as minimizing the negative phenomena that cause dimensional changes after hardening of elements. The tests allowed to determine the most effective hardening conditions in terms of obtained distortions and costs of eliminating distortions. However, the selection of the optimal parameters depends on whether the core hardness requirements are also determined. Originality/value: The conducted tests allowed to determine the most effective hardening conditions in terms of obtained distortions, costs of levelling distortions and a complete technological process for the automotive industry.

РІШЕННЯ ЗАВДАННЯ ОПТИМІЗАЦІЇ ПАРАМЕТРІВ ОБРОБКИ МЕТАЛІВ ПРИ ОПЕРАЦІЇ ТОЧІННЯ

The statement and solution with the application of the intellectual decision support system (IDSS) for optimization of metal processing parameters during the turning operation are shown. The task was posed during the development of IDSS, which allows automating the development of the technological process (TP), optimizing and managing it. The absence of such systems of intellectual support for decision-making does not allow enterprises to fully utilize the capabilities of high-tech equipment and reduces the efficiency and profitability of production due to inefficient use of machine tools, material and engineering resources of enterprises. The tasks of synthesis of the optimal technological process are solved in two stages: the first – structural optimization of the technological process (synthesis of the optimal TP structure); the second – parametric optimization of the technological process (determination of optimal operating parameters for all operations of the technological process). The task of optimizing the parameters of metal processing during the turning operation is one of the subtasks of the second stage of the synthesis of the optimal structure of the technological process of metal machining. The task is solved taking into account the level of accumulated wear on the back surface of the tool, the level of machine efficiency, depending on the operating modes and the period of economically effective tool life. The task is solved in a multi-criteria setting taking into account three objective functions: the cost of operations, the specific energy costs for operations and the operation's performance and the ten existing technical and technological limitations. The solution is obtained as a Pareto-optimal solution. During the solution, an artificial neural network and the genetic algorithm FFGA were applied. This approach allows us to solve the problems of optimization of real production. Shown: the statement of the problem and its practical solution, the structure of the developed system of intellectual support for decision-making, present’s practical results of solving the task, verified the results obtained. The technological map obtained with the help of the IDSS for processing the surface of the «Filter housing» component of the GP-21 generator drive.

Fluoride Removal from Groundwater by Technological Process Optimization

Abstract Fluoride removal from aqueous solutions was studied using nanofiltration and sorption techniques which have always been best key ways to deal with water contaminated by fluoride. In this presented work, we were firstly interested on fluoridated rejected water overcoming the drawback of RO membrane process of groundwater treatment plant in Baltic region (Kretinga, Lithuania). Opoka sorbent has shown effective results of fluoride sorption with efficiency higher than 77 %. In order to understand the sorption phenomenon and to validate the results obtained, we have applied experimental data on Freundlich and Langmuir isotherms which allow us to determine isotherms parameters (KF ; 1/n and KL ; q max) and to confirm the experiment. Because of the unacceptable tariff of drinking water treated by RO, defluoridation with nanofiltration method is proposed in this study as a solution which can replace reverse osmosis technique. For that, tests of nanofiltration for fluoride removal were carried out at laboratory scale by using nanofiltration flat sheet membranes (NF270 and NF90).

Optimal technological process planning approach based on the state of mechatronic systems

The article presents the problem formulation for diagnostics and optimal planning of the trajectory of the technological process taking into account the wear of the mechatronic systems and its electric motors. As an example, we consider a mobile robot with a differential drive, which must successively pass a field of various shapes. The trajectory of movement is chosen taking into account the wear of its electric motors. To solve this problem, it is supposed to use graph theory and probabilistic algorithms. Examples of solutions to the problem are given without taking into account the properties of the soil in the working space of the robot, used by the type of drive and its angle of rotation. The power of sets of feasible solutions will increase significantly with increasing number of technological operations, which, in turn, will lead to inefficiency of using brute force methods for solving the formulated problem and the need to solve it based on probabilistic algorithms agent metaheuristics.

Cleaner production and technical effectiveness: Multi-criteria analysis of copper smelting facilities

The production and use of copper is continually increasing year by year. The modern concept of copper production involves the selection and use of technology which is aimed at preventing the production of large quantities of waste by-products. Increasing the efficiency of the technological process is also important during tendencies to decrease negative impact on the environment. The aim of this paper is to develop a multi-criteria model for selecting the optimal technological process for copper extraction. In order to achieve this goal, the analysis of thirty copper smelters in the world which are using various pyrometallurgical process technologies was performed. The model was developed on the basis of ranking the performance of operating copper smelters by systematically analyzing the technological, economic, and environmental parameters of the technologies applied. PROMETHEE/GAIA methodology of the multi-criteria analysis was used for the modeling. From the aspect of research findings, the results presented in this manuscript fill the literature gap. The major outcome of this research is the obtained model which can have practical merit. The decision-makers, faced with the need of evaluating and selecting the most appropriate technological process for pyrometallurgical copper extraction can benefit from this multi-criteria model. The ranking of available copper technologies applied in different production conditions was done by using the developed model. This resulted in the obtained rank of the available technologies. The findings of the research indicate that optimal results do not come from the best technology but from the best applied and the most appropriate one, depending on the practical conditions, in order to achieve sustainable production, sustainable consumption, and to reduce the impact on the environment.

Methods of criteria optimization of the choice of means of mechanization of construction works

Subject of research: criteria optimization of technological processes of construction works in solving problems of ter­ritorial innovation in settlements with different building density. Purpose : to substantiate the universality of the criterion approach in terms of cost effectiveness for construction works for various purposes on the example of assessing the technological and energy efficiency of the choice of complex mechanization. Materials and methods: theory of large systems, queueing theory, Wald, savage, Hurwitz, Laplace methods, math­ematical analysis. Results: it is proposed to apply a generalized cost indicator as an optimization criterion. The mechanism of complex mechanization of the choice of technical means of providing is accepted key at technological implementation of con­struction projects. The flexibility of the proposed approach in varying the factors of influence, conventionally represent­ing the energy, resource and other characteristics of mechanization. The efficiency of criterion optimization methods in solving problems under conditions of complete uncertainty is proved. Conclusions: the methods of the coordinated analytical and computational model for the selection of optimal energy and functional efficiency sets of mechanization in the implementation of projects of territorial innovation in settlements with different building density are proposed

РАЗВИТИЕ БАЗЫ ЗНАНИЙ ДЛЯ МОДЕЛИРОВАНИЯ ФИЗИКО-ХИМИЧЕСКИХ СВОЙСТВ МЕТАЛЛУРГИЧЕСКИХ СИСТЕМ И ПРОЦЕССОВ

The Institute of Ferrous Metallurgy created the Knowledge Base “Metallurgy” (BDMet). It can be used to model the physicochemical properties of metallurgical systems and processes based on modern computer information technology. The aim of the work is to develop the fundamental foundations and identify the main directions of development of PMD, expand the presentation of fundamental, technological and regulatory reference information for analysis and multi-criteria optimization of technological processes. A component of BDMet is also the Base of models of metallurgical systems and technological processes, applied and theoretical research software. The database contains experimental data on the physicochemical properties of metal and slag melts formed from the corresponding charge materials in reducing and oxidizing conditions. The results of relevant scientific and applied developments of the department of physicochemical problems of metallurgical processes are shown. It is noted that the presence in the BDMet of the stock of models according to redistribution and a unified methodology for their creation on a modular basis allows the generation of models into a single end-to-end model. It also allows you to identify the optimal scheme of metallurgical processes and ensure the production of metal of a given quality in the framework of end-to-end technology. It is shown that the use allows us to solve the problems of optimization of technological processes for the production of iron and steel. The prospects for the development of further studies for systemic accumulation in the databases of documentary factual data and experimental information on the properties of metal and slag melts, as well as their further use in reduction and oxidation processes of metallurgical production, are determined.

Implementation of artificial intelligence in optimisation of technological processes

This article introduces an algorithm for determining optimal parameters of a technological process. The objective function is the processing time of operations (efficiency) at the constraint of quality requirements of finish according to the designer specification. The problem of selecting a correct combination of processing parameters may only be solved when the cause-and-effect relationship between the finish quality and the machining settings is known. If the process considered for optimisation is repeatable, it appears economically viable to invest resources in the development of a model that would describe these relationships. To this end, we propose employing the artificial neural network trained on the progressions obtained from the tests. In the second stage, the Multiple-Input-Multiple-Output (MIMO) system, capable of representing relationships of nonlinear nature, was implemented for the optimisation of the objective function. The paper presents the application of the developed algorithm in determination of optimal parameters for the roller burnishing process of surface treatment. A technologist/software user defines the range of acceptable surface finishes. The optimisation algorithm determines a set of modifiable parameters that ensure minimal processing time at a specified surface finish requirements constraint.

Methods of optimization of technological processes of restoration of steel coverings

Methods of optimization of technological processes of restoration of steel coverings

Побудова хмарних інформаційних технологій оптимізації технологічного процесу відновлення та зміцнення поверхонь деталей

Побудова хмарних інформаційних технологій оптимізації технологічного процесу відновлення та зміцнення поверхонь деталей

Residual stress optimization of technological processes with the aim of ensuring adhesion of nickel or chromium coatings on parts made of titanium alloys

Work on ensuring adhesion of chromium coating on parts piston with a rod made of ВТ3-1, ВТ22 titanium alloys was carried out based on the examination of residual stresses. Ensuring the adhesion of coats was conducted in two stages: at the first stage strengthening treatment was used, and at the second stage optimization of grinding conditions by residual stresses was carried out. A method of predicting process-induced residual deformation by equivalent initial stresses is presented. Residual stresses in a surface layer of specimens cut out of the strengthened parts were studied. It was established that compressive residual stresses in the surface layer ensure the coating adhesion in chromium plating of parts made of titanium alloys. It was shown that ensuring adhesion of coatings on parts made of titanium alloys can be obtained both by strengthening treatment and without it, due to the optimization of grinding conditions. The results obtained made it possible to eliminate surface tempering in the process of grinding parts made of titanium alloys, to ensure favorable technological heredity not only for the parts under examination, but for other parts such as pistons, hydraulic cylinders and rods.

SUBOPTIMAL MANAGEMENT MODEL IN THE TECHNOLOGY OF RADIO-ELECTRONIC EQUIPMENT

In conditions of small-scale production of radio-electronic equipment cost reduction can be achieved through the optimization of technological processes (TP). Discusses problems in the formulation of optimization problems. It is shown that the dynamism, the limited, incomplete and ambiguous information available make traditional methods of optimization management of TP unsuitable for practical use. Topical question of the elaboration of models of governance, which reflect the dynamics of the TP, adapt to changing conditions, are operating under a limited amount of experimental data. The article shows that the problems in the setting and solving optimization problems of TP can be solved using apparatus of the theory of fuzzy sets, the solution is suboptimal. Suboptimal management models designed for model TP small-scale production. Models implement the proposed approach and is suitable for practical use.

Design of production of the range of construction materials on the basis of methods of the system analysis

The analysis of the modern approach to the choice of technological processes of production of heavy concrete products and its weaknesses were shown. It is proved that the technological process as an object is a weekly structured system due to the large degree of uncertainty associated with the human factor. It is established that development of new assortment approach to the choice of technological process of the production of construction materials differing in alleged accounting of functional purpose and service conditions of building constructions in a real estate object can be one version of the solution of this problem. The concept of the choice of optimum technological processes of production of construction materials distinctive in alleged accounting of functional purpose and service conditions of building constructions of real estate objects is developed. The technologies of mathematical statement and the solution of problems of optimization of technological processes of production of the range of construction materials differing in increase in degree of structure of system liaisons with external subsystems on the basis of standard mechanisms of the subject focused accounting of functional purpose and service conditions of building constructions and also standard algorithms of search of optimal solutions for defined the range are developed. Assessment of efficiency of assortment approach to a problem of optimization of technological processes of production of the range of construction materials including comparison of the characteristics of material received as a result of use of modern approach, assortment approach in the set parameters of management and assortment approach with expansion of a set of essential alternatives of technological process of production of the range of construction materials is executed. This assessment has shown that more perspective alternatives on qualitative content of characteristics of material are outside area of normative requirements and need justification.

Development of test operations of different duration in terms of input for the verification of efficiency formula

Determining an indicator for the estimation of effectiveness of system operations is an important stage for optimization of technological processes of any enterprise. This step predetermines the established mode of functioning of all its system processes. The fact that all technological processes should be optimized using an agreed optimization criterion is an axiom. Such a possibility appears only in one case – if we apply the efficiency formula as an optimization criterion in all functional systems. This approach maximizes financial possibilities of the owner of an enterprise. The problem is to identify a structure that corresponds to the structure of the original efficiency formula among a set of evaluation indicators that are identical in terms of formal characteristics. There are classes of standard models of operations define now for the practical solution of this problem. Each of them has its own functional orientation. The most developed are the classes of reference models of simple operations. In relation to the classes of reference models of operations with distributed parameters, there is a solution of the problem operational processes with the same duration in time, as well as for processes with different duration of resource expense by an output. In the proposed study, we define a limited class of models of operations with distributed parameters of different duration by an input. The creation of such a class of operations is quite a difficult task, since it is necessary to take into account a time factor and to enable possibility of comparison of operational processes of different duration. To solve this problem, at the first stage, we formed global models of simple operations of different duration with predetermined rating efficiency. At the next stage, we formed reference models of operations with distributed parameters by an output of different duration by compositing. The development of the verification method by determining a class of operations with distributed parameters in terms of input of different duration in time improves reliability of verification results of the estimated indicator significantly. It is necessary to perform the verification procedure whenever we intended to use it as an indicator of effectiveness

Synthesis of the structure for the optimal system of flow treatment of raw materials

This paper demonstrates that contemporary studies into optimization of technological processes do not take into consideration in the models of systems and in the applied criteria the requirements to the overall efficiency of the process and compliance with the objectives of the owner of a privately-held industrial enterprise. This necessitates the reduction of cost and time of a technological operation, as well as maximization of the added value of the primary product. The effectiveness of the system of a flow treatment of raw materials is estimated using a specialized model, which was synthesized in the course of this work. The proposed model is different in that it includes units to calculate the unit cost of a product depending on the quality indicator and the degree of correspondence to the proposed quantitative and qualitative constraints. There are calculation units for the dynamics of change in a qualitative indicator of the finished product depending on a flow of raw materials and the energy supplied to treatment. The units are also required to calculate the consumption of resource and energy for the transporting and treatingg parts of the system in the interval, defined as the time taken for a conditional batch to pass through the installation. Using the developed model makes it possible to determine the value for the performance indicator for any permissible technological mode and to perform a global optimization of the process. Thus, there is a transition from the requirements to efficiency in general terms to setting the technological process parameters. Here we propose the analytical form for a performance indicator, suitable as an optimization criterion for modes of the technological installation with a continuous supply of raw-material and energy products. We have experimentally studied a model of the flow-through electric heater with units that calculate time and cost parameters, which has demonstrated its adequacy. The developed optimality criterion was verified and the possibility of its application was proven for determining the optimal permissible operating modes of the technological equipment with a continuous supply of raw materials and energy.

Structurally-Parametrical Optimization Technological Process by Dijkstra's Method in System Mathcad

The article describes the procedure of structurally-parametrical optimization of technological process by Dijkstra's method with using of Dijkstra’s functional (recurrent) equation and Mathcad system. The technological process includesnof operations and each operation can be executed by various types of equipment. Expenses (cost, time, ...) on execution ofioperation bykequipment after execution byjequipment (i-1) operation are known -c(i, j, k). The algorithm of the decision of a problem by Dijkstra’s method includes two phases.The firstphase is calculations of the minimum expenses for execution of all partial technological processes, from first operation of process to the last.The secondphase is definition of the required optimum set of equipment which is carrying out all technological process with the minimum expenses from last operation of process to the first. The proposed procedure of structurally-parametrical optimization of technological process using Dijkstra’s method and Mathcad software significantly decreases time and labour costs on execution of such calculations and efficiently to execute investigations related with change of equipment parameters.

Simulation of the ceramic products composition using furnace-waste filler

Modern rates of construction stimulate ceramic-bricks factories to increase volume and variety of their production. At the same time, price of production should not exceed a certain limit. It can be reached by technological process optimization and with using waste of nearby industrial plants. Last time, brick factories try to use solid waste as filler. For regional production, it can be final product of coal combustion from Kazan CHP (Combined heat and power plant). The successful experience of foreign companies in furnace-waste recycling and the production of ceramic products from them, allow us to hope in acceptable results.The purpose of work was modeling composition of ceramic charge for Shelangovsk brick factory using Kazan TPP furnace-waste as filler. As experiment, to composition of clay gross products and working charge (75% clay + 15% sand + 10% buckwheat husks) of the Shelangovsk plant were added 10, 15, 20 and 25 percent of waste dopant. After molding of ceramic small brick, samples were fired at T = 980°C and then the end products were tested for strength.The results showed that addition 10, 15 and 20 percent of ash to working charge are consistently increases the strength of ceramic products in compression tests. According to the requirements of GOST (USSR Standard-Setting Authority) 530-95 for brick and ceramic stones, received products on compression match by brand not lower than M 100; by bend - not lower than M 300. The furnace-waste additive is not so effective with working natural clay. To determine specificity of reactions between waste and charge minerals was used X-ray analysis. Results are showed that ash and slag waste behaves as active fillers and forming new mineral phases.Thus, the use of ash and slag wastes of Kazan CHP as fillers for ceramic charge improves to physical and mechanical characteristics of wall bricks. At the same time, the ash-and-slag additive actively participates in mineral formation and increasing the amount of crystallization contacts in the resulting ceramic products.

Deck method of erecting buildings and embedded structures in the space-limited urban environment

The deckle method of the buildings and embedded structures erection in confined spaces of urban development is dwelt upon. The structural and technological characteristics and combined methods of the works performance when erecting the under- and aboveground parts of buildings according to the closed and semi-closed technologies are described. The fundamental principles on the technological processes optimization are developed: piles installation, ditch sheeting using the method "diaphragm wall", soil excavation under floorings and their erection in terms of maximum saturation with the mechanical aids and continuous organization of works performance. The primary advantages and a complex of the organizational-technological solutions for this technology implementation are described.

АЛГОРИТМ РАЗБИЕНИЯ ПОВЕРХНОСТЕЙ СВОБОДНОЙ ФОРМЫ ПО ЗНАЧЕНИЯМ КРИВИЗНЫ ПРИ ПОДГОТОВКЕ УПРАВЛЯЮЩИХ ПРОГРАММ ДЛЯ СТАНКОВ С ЧПУ

The PURPOSE of the study is to develop an algorithm of free-form surface partitioning into local domains (individual regions), construction of boundaries between these regions and preparation of the initial data for the formation of an optimal technological process of machining and preparation of control programs for shaping such surfaces. METHODS. Partitioning is based on the mean and Gaussian curvature in the points of a free-form surface. The coordinates of the 3D model grid nodes or the data for NURBS surface construction are proposed to be used as initial data or the analysis of the surface region geometry. The Matlab software package has been used for mesh partitioning. A program has been developed to implement the algorithm and determine the coordinates of domain regions which can be imported into any CAD/CAM programs. RESULTS AND THEIR DISCUSSION. The algorithm allows partitioning of free-form surfaces into flat, convex, concave and saddle-type regions. Modern milling machines can be used to obtain these kinds of surfaces on the parts of various products. These machines must be also equipped with the tools of various sizes and product lines. Their number and machining strategies which determine the toolpaths on the surface regions in relation to the workpiece have a significant influence on milling performance. CONCLUSIONS. The obtained data serve as a basis for tool selection and solving of the optimization problem of toolpath planning under multi-axis end milling depending on the shape of the surface regions.

RESISTANT POLYMER NANOCOMPOSITES’ DEVELOPMENT AND INVESTIGATION

Introduction. The advanced technology development demands higher requirements to the physicomechanical characteristics of the polymer composite materials (PCM) widely used in general and special purpose products such as in transport and road-building. This determines the relevance and significance of the new polymer nanocomposites development on the tribotechnical purpose with high physic-mechanical and tribotechnical characteristics. Materials and methods. The problem mentioned above is solved by means of the structural modification’s methods of the PCM polymer matrix and the technological process optimization of the composite materials’ synthesis. One of the structural modification advanced methods is the polymer matrix charging with different fillers’ types, particularly, disperse and fiber ones, and in recent years – ultradispersed and nanodimensional fillers. Results. The composite materials with nanodispersed fillers feature the properties significantly different from those of the materials with microand macrodispersed particles because of the high surface activity of nanodimensional particles’ fillers. Discussion and conclusion. The research deals with the development results and polymer nanocomposites’ investigation with polydispersed and nanodimensional fillers, their influence upon the structure and wear-resistance of the polymer composite materials based on polytetrafluorethylene.