Optimization technological process of machining thin-walled aluminium structures

У оквиру дисертације разматрани су поједини проблеми који се јављају при обради танкозидних структура, који се односе на нетачност димензија, толеранције облика и положаја површина, квалитет обраде површина и производност. Допринос овог истраживања је усмерен на стварање основних и напредних знања у области оптимизације параметара технолошког процеса обраде танкозидних структура од легуре алуминијума с обзиром на дефинисане критеријуме производности, тачности и квалитета обраде. Поред тога, допринос је и у јачању општих и примењених знања везаних за пројектовање и оптимизацију технолошких процеса у индустријским условима. Практична примена резултата истраживања је оријентисана на аутомобилску, војну и ваздухопловну индустрији, као и друге области где се примењују танкозиднe компоненте од алуминијумских легура.U okviru disertacije razmatrani su pojedini problemi koji se javljaju pri obradi tankozidnih struktura, koji se odnose na netačnost dimenzija, tolerancije oblika i položaja površina, kvalitet obrade površina i proizvodnost. Doprinos ovog istraživanja je usmeren na stvaranje osnovnih i naprednih znanja u oblasti optimizacije parametara tehnološkog procesa obrade tankozidnih struktura od legure aluminijuma s obzirom na definisane kriterijume proizvodnosti, tačnosti i kvaliteta obrade. Pored toga, doprinos je i u jačanju opštih i primenjenih znanja vezanih za projektovanje i optimizaciju tehnoloških procesa u industrijskim uslovima. Praktična primena rezultata istraživanja je orijentisana na automobilsku, vojnu i vazduhoplovnu industriji, kao i druge oblasti gde se primenjuju tankozidne komponente od aluminijumskih legura.Within the dissertation, some problems that arise during the machining of thin-walled structures, related to the inaccuracy of dimensions, tolerances of the shape and position of surfaces, the quality of surface processing and productivity, were considered. The contribution of this research is aimed at creating basic and advanced knowledge in the field of the optimization machining process planning parameters of the thin-walled aluminum alloy structures with regard to the defined criteria of productivity, accuracy and processing quality. In addition, the contribution is in the strengthening of general and applied knowledge related to the design and optimization of machining processes in industrial conditions. The practical application of research results is oriented towards the automotive, military and aviation industries, as well as other areas where thin-walled components made of aluminum alloys are applied

Optimization technological process of machining thin-walled aluminium structures

У оквиру дисертације разматрани су поједини проблеми који се јављају при обради танкозидних структура, који се односе на нетачност димензија, толеранције облика и положаја површина, квалитет обраде површина и производност. Допринос овог истраживања је усмерен на стварање основних и напредних знања у области оптимизације параметара технолошког процеса обраде танкозидних структура од легуре алуминијума с обзиром на дефинисане критеријуме производности, тачности и квалитета обраде. Поред тога, допринос је и у јачању општих и примењених знања везаних за пројектовање и оптимизацију технолошких процеса у индустријским условима. Практична примена резултата истраживања је оријентисана на аутомобилску, војну и ваздухопловну индустрији, као и друге области где се примењују танкозиднe компоненте од алуминијумских легура.U okviru disertacije razmatrani su pojedini problemi koji se javljaju pri obradi tankozidnih struktura, koji se odnose na netačnost dimenzija, tolerancije oblika i položaja površina, kvalitet obrade površina i proizvodnost. Doprinos ovog istraživanja je usmeren na stvaranje osnovnih i naprednih znanja u oblasti optimizacije parametara tehnološkog procesa obrade tankozidnih struktura od legure aluminijuma s obzirom na definisane kriterijume proizvodnosti, tačnosti i kvaliteta obrade. Pored toga, doprinos je i u jačanju opštih i primenjenih znanja vezanih za projektovanje i optimizaciju tehnoloških procesa u industrijskim uslovima. Praktična primena rezultata istraživanja je orijentisana na automobilsku, vojnu i vazduhoplovnu industriji, kao i druge oblasti gde se primenjuju tankozidne komponente od aluminijumskih legura.Within the dissertation, some problems that arise during the machining of thin-walled structures, related to the inaccuracy of dimensions, tolerances of the shape and position of surfaces, the quality of surface processing and productivity, were considered. The contribution of this research is aimed at creating basic and advanced knowledge in the field of the optimization machining process planning parameters of the thin-walled aluminum alloy structures with regard to the defined criteria of productivity, accuracy and processing quality. In addition, the contribution is in the strengthening of general and applied knowledge related to the design and optimization of machining processes in industrial conditions. The practical application of research results is oriented towards the automotive, military and aviation industries, as well as other areas where thin-walled components made of aluminum alloys are applied

APPLYING PRECEDENCE RELATIONSHIPS AND CAD/CAM SIMULATION IN TIME-BASED OPTIMIZATION OF PROCESS PLANNING

Optimization of process planning belongs to the group of combinatorial optimization problems which at the macro and micro level consists of the selection of machining operations, definition of sequences of machining operations and their grouping into processes, selection of manufacturing resources, machining parameters and strategies. The objective function used for evaluating process plans is mostly defined by manufacturing cost, manufacturing time, surface quality and surface accuracy. The main goal of this research refers to the process planning and optimization of manufacturing time by applying precedence relationships among machining operations, as well as the simulation technique within the CAD/CAM system. The precedence relationships are defined on the basis of dimensional, geometric, technological and economical precedence constraints. Based on these rules, precedence matrices for determining operation sequence for the given shaft part are formed, and afterwards, machining operations are grouped into appropriate processes. For the given rational variants of process plans, a simulation of machining process is performed within the Catia software system. The obtained output is the best variant of process plan for the shaft part on the basis of manufacturing time as the adopted objective function

Application of STEP-NC in the integration CAX and CNC systems: Case studies

The paper describes possibility of implementation the STEP-NC in process planning for CNC machining, and integration of CAx and CNC systems. Proposed are two variants of possible applying, with verification on example. As software for the realization of CAD/CAM activities were used Pro/E and Catia, while for generate STEP-NC programs and management information to process used software STEP-NC Machine

Application of STEP-NC in the integration CAX and CNC systems: Case studies

The paper describes possibility of implementation the STEP-NC in process planning for CNC machining, and integration of CAx and CNC systems. Proposed are two variants of possible applying, with verification on example. As software for the realization of CAD/CAM activities were used Pro/E and Catia, while for generate STEP-NC programs and management information to process used software STEP-NC Machine

Prioritization of manufacturing sectors in Serbia for energy management improvement - AHP method

Manufacturing, which is destined to play the most significant role in the reindustrialization of Serbia is also one of the largest energy consumers and environmental polluters. In accordance with this, a large number of energy and environment management initiatives have been implemented over the years. In developed countries, these initiatives are at an advanced level, but not in Serbia. A group of manufacturers in Serbia has recognized the significance of the environmental initiatives implementation, but the interest in energy management improvement has remained low. Although these initiatives can be used to achieve cost reduction in industry, not all the manufacturing sectors equally value the importance of energy management improvement. Among all the manufacturing sectors, it is necessary to prioritize those with the potentials for energy management improvement, which can be done using different methods. In this paper, the AHP (Analytic Hierarchy Process) method was used to prioritize manufacturing sectors in Serbia in the area of energy management improvement. Using a created AHP questionnaires criteria weights were selected. These questionnaires were completed by the experts from the Serbian Chamber of Commerce and Industry, providing us with the opportunity to evaluate the Serbian manufacturing sectors based on the real life data. The results of the AHP method, which was used as the prioritization instrument, and their analysis are presented in the paper. As a part of a wider study, aimed at the improvement of the energy management in Serbia, the three manufacturing sectors with the highest priority (Manufacture of food products, Manufacture of motor vehicles, trailers and semi-trailers, Manufacture of other non-metallic mineral products) will be analyzed in the future research in terms of energy process flows, energy management system implementation and other relevant issues. (C) 2015 Elsevier Ltd. All rights reserved

Energy management system implementation in Serbian manufacturing - Plan-Do-Check-Act cycle approach

In Serbia, a developing country, energy consumption per capita is higher than in most other countries in the region. Implementation of energy management practices is therefore necessary to cut energy consumption and CO2 emissions. This paper gives an insight into how energy management is implemented in Serbian manufacturing (focusing on food processing and manufacturing of non-metallic mineral products, defined as priority industrial sectors). No similar study for Serbian manufacturing has been published. The study was carried out using an on-line questionnaire based on the ISO 50001 requirements. Questions were grouped into 16 categories and presented according to the PDCA (Plan-Do Check-Act) cycle. The propbsed methodology has not been used by other researchers for similar problems. The survey was conducted in 52 organizations and lasted from May to December 2015. We found that the average level of requirements fulfillment in priority industrial sectors in Serbia is 59.05%. Full implementation was found in only 5.8% of participating organizations. Average implementation of the PLAN phase (establishing basics for energy management) is 61.87%, implementation of the DO phase (realization of energy management processes) is 59.98%, implementation of the CHECK phase (monitoring and measurement of energy performance) is 59.61%, and finally, implementation of the ACT phase (review and improvement of energy management) is only 3534%. The study results offer scientific data for improving national policy and education on energy management in Serbia. (C) 2017 Elsevier Ltd. All rights reserved

Multi-criteria selection of the optimal parameters for high-speed machining of aluminum alloy Al7075 thin-walled parts

Thin-walled parts made of aluminum alloy are mostly used as structural elements in the aerospace, automobile, and military industries due to good homogeneity, corrosion resistance, and the excellent ratio between mechanical properties and mass. Manufacturing of these parts is mainly performed by removing a large volume of material, so it is necessary to choose quality machining parameters that will achieve high productivity and satisfactory quality and accuracy of machining. Using the Taguchi methodology, an experimental plan is created and realized. Based on its results and comparative analysis of multi-criteria decision making (MCDM) methods, optimal levels of machining parameters in high-speed milling of thin-walled parts made of aluminum alloy Al7075 are selected. The varying input parameters are wall thickness, cutting parameters, and tool path strategies. The output parameters are productivity, surface quality, dimensional accuracy, the accuracy of forms and surface position, representing the optimization criteria. Selection of the optimal machining parameter levels and their ranking is realized using 14 MCDM methods. Afterward, the obtained results are compared using correlation analysis. At the output, integrative decisions were made on selecting the optimal level and rank of alternative levels of machining parameters.Web of Science1012art. no. 157

The possibilities for application of STEP-NC in actual production conditions

With the rapid advancement of internet technologies (IT) and computer numerical control (CNC) technologies, the production environment has significantly changed in the last two decades. The International Organization for Standardization (ISO) standard 6983 (G-code), which is still being used as a link between computer aided design/computer aided process planning/computer aided manufacturing (CAD/CAPP/CAM) and CNC system, represents an obstacle for the full integration of design and manufacturing. The result of efforts to eliminate these obstacles and shortcomings of developed standards for data exchange and sharing is the development of (STEP-ISO 10303) standard, as well as its extension to numerical control STEP-NC. This paper shows the current possibility of implementing STEP-NC in integration of computer aided technologies CAx and CNC systems in actual production conditions. Two scenarios represent a new approach to programming CNC machine tools using the STEP-NC protocol, which is explained in detail with IDEF0 diagrams, with defining necessary equipment and software. Implementation of the STEP-NC protocol described by the integration definition for function modeling (IDEF0) methodology was experimentally verified on specific examples for both scenarios, with the application of available CAD/CAM systems and the STEP-NC machine software, as well as appropriate virtual and physical CNC machine tools