Inteligentno upravljanje, modeliranje i optimizacija procesa livenja

In the framework of the doctoral dissertation, it is presented a development of control, modeling and optimization of the casting process, based on application of artificial i.e. computational intelligence methods. Improving of production processes in foundries, in the framework of researches that contains doctoral dissertation consist of modeling of metal melting process, optimization of sand casting system and control of gravity casting process. The first part of research deals with modeling of melting metal in furnaces. It is a complex process due to dynamics of non-linear chemical reactions. Conventional mathematical and thermodynamical models, which are certainly helpful, are not fully reliable due to complex interactions of process variables. Neural networks, as one of the key techniques of computational intelligence, are able to identify internal relationships through training examples. As such, they are used as an effective tool in defining the needed chemical composition of the molten metal by providing alloying process improvement. Proper and complete mold filling is the main objective of the sand casting process, which ensures high quality of the casting part. To this end, the designs of the gating system and feeding system is of major importance, as improper designing of the system results in a number of defects in the casting process, e.g. low quality of the casting part. Тherefore, the gating system aims at providing a smooth, uniform and complete filling of the mold with pure, molten metal. Smooth filling eliminates turbulence, uniform filling ensures continuous mold filling, whereas complete filling allows the molten metal to reach minor, end cavities of the mold. During cooling casting part comes to the volume metal shrinkage, ie. reducing the volume of casting part. The importance of feeders is in their function to compensate the lack of molten metal in the casting part due to volume shrinkage. The second part of research is an optimal construction of gating system and feeders, which satisfy the requirements with high quality casting part and savings of materials. The combination of global optimization method and CAD/CAM software has provided the possibility of effective optimization, design and verification of optimal solutions by numerical simulation. Unlike some other industrial processes, many casting plants have not benefited from the advanced automation therefore the process of filling the mold cavity is still manually performed. Automated systems that minimize the participation of workers and enhance the precision of casting, are also the subject of research in this doctoral dissertation. The part of research, which is dedicated to the development of casting process control, contains a proposal of an automated system in casting plants, development of laboratory simulator of the casting process and the development of possibility of application of intelligent control of mold filling

Application of CAD/CAE/CAM Systems in Permanent-Mold Casting Improvement

This paper presents the application of CAD/CAE/CAM systems at the improvement of the manufacturing the flotation balls for grinding ore. Flotation balls need to satisfy the appropriate requirements in terms of dimensional, chemical, mechanical and physical properties. These properties are directly related to technology of ball manufacturing, in this case - permanent-mold casting technology. Software tolls from the group of CAD/CAE/CAM systems were used for designing the casting parts, casting and feeding systems, mold and simulation of permanent-mold casting process. Based on results of casting process simulation the casting process in real industrial conditions was realized. After the casting process, testing of casting parts has been performed. The testing gave satisfactory results, so the presented methodology, based on CAD/CAE/CAM systems, is acceptable for manufacturing program in foundry

Pseudoachondroplasia: A case report

Introduction. Pseudoachondroplasia (PSACH) is an autosomal dominant osteochondrodysplasia due to mutations in the gene encoding cartilage oligomeric matrix protein. It is characterized by rhizomelic dwarfism, limb and vertebral deformity, joint laxity and early onset osteoarthrosis. We present the girl with the early expressed and severe PSACH born to clinically and radiographically unaffected parents. Case Outline. A 6.5-year-old girl presented with short-limbed dwarfism (body height 79.5 cm, <P5; -32%) and normal craniofacial appearance and intelligence. The girl was normal until 3 months of age when she expressed growth retardation with apparently shorter extremities in relation to the torso. With age, her rhizomelic dwarfism became increasingly visible, and since completed 15 months of age, when she started to walk, the disease was complicated with genu varum, lumbar lordosis and abnormal gait. Beside visibly short forearms, short, broad and ulnar deviation of the hands, brachydactyly and joint hyperlaxity, the radiographic picture showed markedly flared metaphyses, small and irregular epiphyses and poorly formed acetabulum. Conclusion. PSACH is an achondroplasia-like rhizomelic dwarfism recognized by the absence of abnormality at birth, normal craniofacial appearance, characteristic epiphyseal and metaphyseal radiographic finding and joint hyperlaxity

IMPROVING THE MECHANICAL CHARACTERISTICS OF THE 3D PRINTING OBJECTS USING HYBRID MACHINE LEARNING APPROACH

Production of three-dimensional parts in 3D printing process gains growing importance in various fields, such as: aviation and car industry, architecture, medicine, dentistry, etc. Mechanical performance is an important users’ requirement for manufacturers of 3D printed parts. Furthermore, printed part highly depends on process parameters, position and orientation of the printed part, and performances of the 3D printer which prints the part. In this paper, based on experimental results, an artificial neural network has been used for modeling the dependence of process parameters and object orientation during printing, on the one side, and tensile strength as very important mechanical performance, on the other side. After establishing abovementioned dependence, the developed neural network has been used as a fitness function for the genetic algorithm while the genetic algorithm has been created for the optimization process. The result of optimization process was a set of optimal process parameters and part orientation giving the maximum tensile strength. The results have shown acceptable potential of the developed methodology for optimizing the 3D printing process as a complex engineering problem

Improvement of study programs for bachelor’s and master’s studies in Mechatronics in response to the requirements of Industry 4.0

This study was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia, and these results are parts of the Grant No. 451-03-68/2022-14/200132 with University of Kragujevac - Faculty of Technical Sciences in Čacak.Development in information technology has resulted in revolutionizing all aspects of life and this revolution has been realized as Industry 4.0. A main approach that universities' educational systems may take towards Industry 4.0 is educating students who have the right skill set for reacting to the changes in their working environment, adapting their performance, and learning to cope with technological development. This paper presents the results of the project "Improvement of study programs for bachelor's and master's studies in Mechatronics in response to the requirements of Industry 4.0", which was funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia as a part of program activity "Development of higher education" and performed in the 2020/21 academic year.Publishe

CASTING IMPROVEMENT BASED ON METAHEURISTIC OPTIMIZATION AND NUMERICAL SIMULATION

This paper presents the use of metaheuristic optimization techniques to support the improvement of casting process. Genetic algorithm (GA), Ant Colony Optimization (ACO), Simulated annealing (SA) and Particle Swarm Optimization (PSO) have been considered as optimization tools to define the geometry of the casting part’s feeder. The proposed methodology has been demonstrated in the design of the feeder for casting Pelton turbine bucket. The results of the optimization are dimensional characteristics of the feeder, and the best result from all the implemented optimization processes has been adopted. Numerical simulation has been used to verify the validity of the presented design methodology and the feeding system optimization in the casting system of the Pelton turbine bucket

CAD/CAM DESIGN AND GENETIC OPTIMIZATION OF FEEDERS FOR SAND CASTING PROCESS

The paper proposes methodology of feeder design and optimization for sand casting process. Casting part is a part of excavator buckets, i.e. holder of the cutting tooth. Process of design and optimization is based on the application of the rules, which are the result of many years of work researchers in the field of metal casting. Computer Aided Design (CAD) is used as a methodology in the design of feeders. Genetic Algorithm (GA) as an artificial intelligence technique is used in the optimization process of the feeder geometry. Computer Aided Manufacturing (CAM) is used as methodology that involves numerical simulation of the casting process. Numerical simulation is used to verify the validity of the optimized geometry of the feeding system

The influence of multifunctional microalloyed ceramics microstructure on its capacity properties

Modified porous alumo-silicate ceramics, alloyed with magnesium and microalloyed with aluminum, belongs to modern multifunctional ceramic materials. Microalloying has led to important changes in dielectric and electrical properties of ceramics, such as dielectric constant and electrical resistance. These changes are conditioned by the microstructural properties of modified porous ceramics. The obtained results have shown the unity of the influence of composition, structure, morphology and application of microalloyed multifunctional alumosilicate ceramics on electrophysical properties. Microstructural investigations have shown that this type of ceramics has an amorphous-crystal structure, which causes important changes in its electrical properties and affects its activity. Therefore the ceramics can be considered as an active dielectric. A correlation between microstructural properties and structurally sensitive, i.e. electrophysical properties of microalloyed multifunctional alumo-silicate ceramics, was confirmed

The elimination of the anti-coincidence colorimetry in the process of painting the shell of a vehicle by applying WCM

This work presents the optimization of process of car shell painting in FCA Serbia Ltd. by using the world class manufacturing (WCM). In order to show the advanced Kaizen within the pillar "Focused improvement" we have taken an example of problems in the production of a passenger vehicle "Fiat 500L" which is reflected in an inadequate colour match during serial production. The anticoincidence in the process of painting the shell of a vehicle was eliminated by Kaizen method. The analysis of vehicle shell painting process improvement was carried out by DOE, the verification of the proposed activities was completed, the experiment factor was identified, a hypothesis testing was conducted, all results were viewed and the process of verification and optimization was completed.Publishe

Integrisan proces proizvodnje abrazivnih reznih elemenata bagera u rudarskoj industriji

The paper presents an integrated production process for excavator cutting elements in the mining industry based on modern software systems for the optimization and management of casting process parameters through simulations. The concept involves the virtual manufacture, practical implementation of the established technological process and quality control of final castings i.e. excavator cutting elements. The presented production methodology reduces the time required to develop and manufacture the new product compared to the traditional methods of prototype testing.Publishe