Scientific Bulletin Series C, Volume XX (2006)
ASPECTS REGARDING THE LUBRICANT FILM THICKNESS TO THE RADIAL HD WORKING BEARING UNDER HARD SHOCKS
Marius Alexandrescu, Eugen Pay, Mihai Tiron, Flavian Farcaş
Abstract: Due to the very short time of loading radial bearings exposed to shocks and vibrations, of about 0.5-1 ms, this paper presents a few experimental assessment concerning the function of radial bearings with HD lubrication in the case of huge challenging working. It was focussed on the determination of the lubrifiant film resistivity and minimal resistance on the lubricant film, which estimates the minimum lubricant thickness between spindle and bushing.
Keywords: bearing, radial hydrodynamic bearing, lubrifiant film resistivity.
EXPERIMENTAL ASSESSMENT CONCERNING THE HD RADIAL BEARINGS IN THE CASE OF DYNAMIC CHALLENGING WORKING
Marius Alexandrescu, Eugen Pay, Mihai Tiron, Flavian Farcaş
Abstract: Due to the very short time of loading radial bearings exposed to shocks and vibrations, of about 0.5-1 ms, this paper presents a few experimental assessment concerning the function of radial bearings with HD lubrication in the case of huge challenging working. It was focussed on the determination pressure distribution from the film to be lubricated in various places of the bearing′s body.
Keywords: bearing, pressure distribution, radial hydrodynamic bearing, impulse loading.
RELIABILITY RESEARCH OF PUMP RODS UNDER WEAR-FATIGUE CONDITIONS
Volodymyr ARTYM, Petro PUSHKAR, Yaroslav FEDOROVYCH, Roman KARPYK
Abstract: The paper is dedicated to development of the experimental method for study of longevity of pump rods under influencing of wear, corrosion attack and fatigue. The construction of plant for studies is proposed. The results of experiment are displayed. It is drawn a conclusion, that in a usual terms of sucker rod string exploitation (hold-down pressure of pump rods to flow string up to 100 N) the frictional component of the process of corrosion frictional fatigue not only does not moderate, but even rises pump rods durability on curved parts of borehole.
Keywords: pump rod, fatigue, friction, corrosion, durability.
DYNAMICAL OPTIMIZATION OF THE TIP RELIEF PARAMETERS FOR AN INVOLUTE SPURS GEARING WITH IMPOSE CENTER BASED ON COMPUTER SIMULATION
Mihai BĂNICĂ, Radu COTEŢIU
Abstract: For the nonce of high precision’s spurs gearing, the classical design algorithm does not ensure the necessary precision. In these cases, the computer simulation of the spurs gearings behavior and its dependence on the design, technological and operating parameters depict a viable choice. The paper analyzes the influence teeth shape (addendum modification coefficients) and the rotation speed on the tip relief parameters, based on computer simulation (original software builds on MatLab7 program), for an involute spurs gearing with imposed center with the goal of equal traction tensions at the level of the teeth base.
Keywords: tip relief parameters, static and dynamic hypothesis, addendum modification, rotation speed.
APLICATION OF COMPUTER AIDED RISK VALUATION USING SCORING METHOD
Petr BARON, Peter BRÁZDA
Abstract: Paper describes possibilities of using computer calculations in human and technical risk valuation process using combine technique of Catalogue sheets method and Scoring method. Article presents behavior of proposed software application by risk matrix generating, which represent support in decision making process of risk valuation analyzes.
Keywords: Risk, Probability, Inference, Danger, Menace.
ALGORITHM FOR DETERMINING THE PARAMETERS OF THE GEAR RACK WITH ASYMMETRICAL TEETH
Flavia Chira, Anamaria Dăscălescu
Abstract: This paper intends to establish the analytical relationships of an algorithm for calculating the parameters of the gear rack with asymmetrical flanks, with the aim of creating a design program, which would allow the creation of a gear rack for a gear with asymmetrical involute teeth, starting from the generalized parameters of the gear.
The generator edge radius is a parameter that influences tension concentration at the tooth root, thus directly influencing its resistance. The gear rack tooth height must ensure the realization, without interference, of the two asymmetrical profiles.
Keywords: spur gears, asymmetric profiles, involute teeth, rack-cutter.
SOME ASPECTS OF FINITE ELEMENTS ANALYSIS METHOD APPLIED USING CAD SYSTEMS
Horia CIOBAN
Abstract: The paper presents some cases of study using the FEA method in the design activity; the study shows the different stages of the 3D model, the loads and constrains applied on the digital product; Stress Analysis was used to simulate the behavior of a mechanical part under structural loading conditions.
Keywords: -.
GEOMETRIC METHOD OF UNDEFORMED CHIP STUDY IN BALL NOSE END MILLING
Marius Cosma
Abstract: The objective of this study is to give emphasis about some aspects in geometric analysis of chip generating mechanism in metal cutting by milling, using ball nose end mills. A ball nose end mill has a semi-sphere at the end tool and has very complex machining mechanism in chip generations. Ball nose cutters cut with the radius of the ball, from the tip of the tool to the tangency point at full diameter. The cross-section of the chip produced by a ball nose cutter resembles a section of a crescent moon. At shallower axial depth of cut the crescent is thinner, the chip thickness is less and the volume of material removed is also less. In this study the volume of undeformed chip and a few representatives cross-section are obtained in 3D-CAD, by four surfaces intersection. With the prevalent use of ball nose tools in the milling of dies and molds or complex surface parts from different area of industry, chip thinning can become an important productivity-enhancing tool.
Keywords: ball nose end mill, cutting edge, chip geometry, milling, tool paths.
AUTOMATIC ADJUSTMENT SOLUTION WITH FLUIDIC ELEMENTS FOR THE PNEUMATIC INDUSTRIAL EQUIPMENTS
Adriana COTEŢIU, Mioriţa Ungureanu, Dinu Stoicovici
Abstract: This paper presents the actual solution used by Tamrok Enterprise and a personal solution for the implementation of the digital devices in the pressing strength’s control of a pneumatic rotating hammer drill, which is included in the structure of the perforator installation. The monostable element, which was proposed to use, is a special device with an incompressible fluid as supply jet and compressible fluid as command jet.
Keywords: bistable element, monostable element, automatic adjustment of the pressing force, advance force, pneumatic rotating hammer drill.
LIFE CYCLE ASSESSMENT METHODOLOGIES AND DATABASES
Radu COTETIU, Vasile NASUI , Mihai BANICA
Abstract: A huge number of methodologies, databases and software tools are available This paper presents a synthetic view about one of the most important action in eco-design about selection of methodologies and tools. Currently a project is under way to set up an Internet site on life-cycle assessment tools and services and life cycle inventory data in support of European Integrated Product Policy.
Keywords: -.
THE RELIABILITY OF THE MEDICAL MECHANICAL SYSTEMS INTERVERTEBRAL DISC PROSTHESES
Monica-Iliuta Cretan, M.Gafitanu, Fl. Munteanu
Abstract: The Intervertebral Disc Prostheses consist of a modular system and his function is based on low intervertebral friction. As a result of friction forces acting to the spine structures, the intervetebral disc prostheses can develop wear phenomena of the polymeric nucleus. From a tribological point of view the most important problems are the friction and the wear, specifics to the endoprostheses system, because these two phenomena dictate their durability. The development of friction processes at the most tribosystems level can be made in direct mode. In this sense, the development on the tribomodels who simulates the normal joint function is the most used solution. As a measuring method of these tribological parameters was used different versions of these laboratory installations or stands, we observed the wear of the moving prosthetic devices and we calculated the tribological parameters.
Keywords: prostheses, tribosystem, wear, stands, parameters.
PERFORMANCE OF HEAVY-DUTY PLANETARY GEARS
Attila Csobán, Mihály Kozma
Abstract: Wind energy is widely spread in the world owing to the shortages of fossil energy and its environmentally friendly character. The economy of wind turbines can be increased using large equipment producing electric power up to 5 MW. Large wind turbines need heavy-duty drive systems with great power/weight ratio, high efficiency and high gear ratio. There were performed theoretical investigations on heavy-duty planetary gears being able to transfer the high power from the wind turbine to the generator.
Keywords: Planetary gear, differential gear, wind turbine.
THE UTILIZATION OF COMPUTER SIMULATION AT MACHINING PROCESS OPTIMIZATION IN ENGINEERING INDUSTRY
Nadežda Čuboňová, Ivan Kuric, Ján Ščamba
Abstract: The article presents analyse of computer simulations problem in real computing, short wiev of computer simulation models, summary of the mathematics models used at computer simulation, determination process at simulation methods selection, real applying and utilization at machine industry, contribution of analyse in machine industry.
Keywords: computer simulation, computer model, optimisation, and machine industry.
COMPATIBILITIES OF THE CAD – CAM PROGRAMS APPLIED TO THE CYCLOID PROFILE WHEELS PROCESSING
Anamaria Dăscălescu, Flavia Chira, Liliana Drăgan
Abstract: The classic manufacturing process of the cycloid profile involves important technological problems. Therefore, in this paper we propose a computational method of manufacturing and control process of the cycloid satellite gears, based on the theoretical 3D Model (obtained in CAD program) using compatibles CAD-CAM programs. The same computational method can be used in generating, manufacturing and control process of other complex profiles assuring the precision of the real profile related to the theoretical 3D model.
Keywords: generation, analyzing, simulation, manufacturing, control.
ABOUT KINEMATIC REDUCED MODEL OF LOWER LIMB
Liliana Drăgan
Abstract: The paper presents the complete and the reduced model of the lower limb.It can be modelled as an kinematic chain consisting of several links connected by revolute joints driven by actuators. For geometric and kinematic modelling of the reduced model with 5 dof it is used a DH –convention.
Keywords: biokinematics, lower limb, reduced model.
THE USE OF “SAFETY ECOLOGICAL INTEGRATORS” FOR THE ASSESS MENT OF THE ATMOSPHERE CONTAMINATION DEGREE IN ORDER TO ENHANCE THE POPULATION LEVEL OF HEALTH
Angelica DRAGHICI, Dragoş VASILESCU
Abstract: ”Safety ecological Integrators” are tools used to check the ecological security for the health of the population in research – development activities of the ecological systems, which allow the designer to develop the specific functions of ecological security in the assessed environmental system and they require the approach of the specific environmental risks, the warning measures as well as the cost restrictions for implementing these measures, allowing:
– checking the coverage of the identified environmental risks;
– analyze of the required ecological security functions relative to expenses;
– solutions proposals for the integration of the ecological safety in the analyzed environmental system.
The use of the method “Safety ecological Integrators” provides necessary information and data
regarding the level of contamination of the atmosphere referable to the designed environmental system ass well as the enacting the decision to submit this system (or its components) to the procedures for the performing of the special audit of ecological security.
Keywords: Environmental, ecological integrators, population level, safety ecological.
EXPERIMENTAL RESEARCH ABOUT TOOTHED GEARS MADE OF PLASTIC MATERIALS UNDER ADHESIVE AND ABRASIVE CONDITIONS
Otto-Paul Eberst, Robert Keresztes, Elena-Angela Pop, Sever Pop
Abstract: In this work are presented the results of experimental research regarding the wearing of cylindrical toothed gears with straight teeth and with one gear made of steel and the other made of different high performance plastic materials. The wearing are studied under slightly overloaded conditions both for dry friction (purely adhesive) and for friction realized with abrasive quartz (siliceous sand) particles.
The conclusions presented here are useful at chooseing the mostly proper plastic material for toothed gears and for frictions existing under some specific technical condition.
Keywords: plastic/steel toothed wheels, slight overload, adhesive and abrasive wearing.
AVAILABILITY OF TECHNOLOGICAL EQUIPMENT
Carmen Florea, Alexandru Florea, Stela Dinescu
Abstract: The maintenance and repair systems are based on a logical scheduling of activities, simultaneously with the monitoring of operating behavior of equipment. The paper deals with the availability analysis for complex systems of equipment in large lignite open pits in Romania.
Keywords: availability, reliability, maintainability open pit mining, excavator.
PREDICTIVE MAINTENANCE TECHNOLOGIES ASPECTS
Adrian GHIONEA, Răzvan BUDICĂ, Ionut GHIONEA, Cristina IBRAIM
Abstract: The evolution of the maintenance concept is determined by the technical and economical organization evolution of factories and manufacturing. Predictive maintenance is an evaluation activity of a status of a mechanism, assembly or system before its breakdown. The purpose is to avoid longer interruption of the mechanism, assembly or system working. This could affect productivity or customer satisfaction. In this paper, some methods and technologies applied in monitoring/diagnostics activities are presented in order to determine deterioration, the main causes (vibrations, noise, loading, exploitation) and their effects. Monitoring/diagnostic capability of the system has been developed including computer usage.
Keywords: monitoring/diagnostic, maintenance, defects, component/equipment/machine.
CONCEPT OF DIMENSIONING AND DEVELOPMENT OF BULK MATERIAL STOCKPILS
Iosif Gruneantu, Iosif Andras, Sorin Noaghi, Livia Ilias
Abstract: In market economy conditions, where discrepancies may occur between demand and offer, coal deposits resulted from exploitation are indispensable elements of producing, processing or consuming units. A concept was developed for the sizing and building of deposits, characterized by simplicity, maximum efficiency and minimum investments. A correlation was established between accumulation capacity, technical-functional characteristics and size of deposits.
Keywords: -.
EPICYCLIC GEAR WITH FRICTION GEARING AND CARDAN MECHANISM
Jozef Haľko, Ján Paško, Slavko Pavlenko
Abstract: The problem of epicyclic gear with cardan mechanism based on friction gearing is presented in the paper. The authors emphasize the possibilities of gear and force ratios in the mechanism.
Keywords: epicyclic gear, cardan mechanism, friction gearing, high accuracy transmission.
PARAMETERS INFLUENCE ON CROSS SIZE OF CUT RIFT AT PLASMA ARC CUTTING
Michal Hatala, Robert Čep
Abstract: At nowadays expansion of use of plasma arc cutting in praxis a lot of novel question rise up connected with this process. Paper describes parameters, which influence cut rift at plasma arc cutting, what is important in term of material save in manufacturing process.
Keywords: plasma arc, cut rift, meltings.
MATHEMATICAL MODEL FOR ESTABLISHING THE VIBRATING CONDITIONS SPECIFIC TO ELECTROMAGNETIC SIEVES
Mircea Horgos, Mihai Banica, Dinu Stoicovici
Abstract: The theoretic bases of some mathematical models for the sorting processes on vibrating sieves were established once the modern calculation equipment appeared. The present paper presents a simplified calculation model for vibrating conditions specific to the sieving of pulverized materials on electromagnetic sieves.
Keywords: sorting process, electromagnetic sieves, false position method.
CONSTRUCTIVE DESIGN PRINCIPLES APPLIED TO ENHANCE SUPPORT EQUIPMENT QUALITY
Nicolae Iliaş, Iosif Andras, Attila Kovacs, Andrei Andras, Emanoil Venescu, Livia Iliaş
Abstract: The present paper examines practical application of the principles of constructive design in order to increase the quality of supporting equipment for mining industry.
Keywords: Quality, TQM, longwall mining, support shield.
ABOUT ECONOMIC RESTRUCTURING ON MONOINDUSTRIAL MINING AREAS TARGETED TO SUSTAINABLE DEVELOPMENT
A.L., Ispas, E., Moisescu, A. Nicola, L. Craciun
Abstract: Nowadays Romania is preparing to enter into the European Union. In this respect the large enterprises must be adapted to the restructuring, modernization and making profitably. The paper present the Romanian industrial system structure, the future role of large enterprises in accordance with their privatization and restructuring: Monoindustrial regions from Eastern and central Europe, being in transition towards market economy, represent the target of restructuring policies. The consequences of desindustrialization, make the process of transition more painful as at national level. These regions possess non utilized resources but are characterized by the lack of alternatives, due to their former status. In order to insure a sustainable development of these regions, and overcome the inherited strengths and weaknesses it is necessary to combine regional development policies with nationwide development strategies. A few aspects of these topics are treated in the paper.
Keywords: -.
CONTRIBUTIONS ABOUT GANTRY MACHINE TOOL GEOMETRIC ACCURACY IMPROVEMENT BY LASER ALIGNMENT
Constantin ISPAS, Dorel ANANIA, Constantin DOGARIU, Dragos TILINA
Abstract: Linear measurement is the most common form of measurement performed with a laser. The laser system measures linear positioning and repeatability by comparing the position displayed on the axis read-out with true position measured by laser system. Positioning errors in the Gantry machine tool axis are measured and captured using a laser interferometer system comprising a Renishaw ML 10 laser, EC10 environmental unit, linear optic components and a PC.
Keywords: machine tools repeatability and linear accuracy, laser interferometer system, optic components, high speed machining.
PRODUCT DEVELOPMENT USING CAD-CAM-CAE SOFTWARE AND INTERNET FACILITIES
Constantin ISPAS, Miron ZAPCIU, Cristina MOHORA, Dorel ANANIA
Abstract: The main goals to the product development are to obtain a short time of design process, a low price and best performances of the final product. According to these goals, the product design must use some modules of advanced CAD-CAM-CAE software and the internet on-line 3D catalogs for some parts (more or less standard). The advantage obtained by using some modules from different CAD-CAM-CAE software is to use the most performant parts of these software (specific to the engineering fields) at a low price (it isn’t necessary all the software, only some specific modules). The internet 3D on-line catalogs offer the advantage to find very easy useful information about mechanical elements (prices, technical characteristics, 3D models, etc,).
Keywords: CAD-CAM-CAE software, internet on-line catalogues, on-line portal 3D catalogues, standard elements, integrated product design.
THE STATE OF STRAIN AND DISPLACEMENTS FROM THE STRUCTURE OF THE TOWERS OF THE EXTRACTING INSTALLATIONS WITH WESSELS AND DOUBLE PULLEYS IN THE CASE OF THE APPLYANCE OF THE EMERGENCY BRAKE
Vilhelm Itu, Iosif Dumitrescu, Mihai Ridzi
Abstract: In the paper there are presented certain aspects concerning the determination of the state of strain and displacements from the structure of the towers of the extracting installations due to the loads transmitted through the bearings of the extracting pulleys in the case of the application of the emergency brake, on the increase of speed above the maximum admitted, a case considered perturbation or emergency.
Keywords: Strains, displacements, tower, extracting installation.
IMPROVING THE CAST PA-6 SURFACE DURING MACHINING
Gábor Kalácska
Abstract: In the literature there are many tables offering wide range of cutting, machining parameters for the different semi-finished engineering polymers. It is well-known that the surface parameters of the technical surfaces can influence the potential possibility of a certain machine element. This statement is also true for the machined engineering polymers regarding the load-carrying capacity and tribological behaviour.
From the engineering practice also known that the machining behaviour of the POM C is desired by the technicians. In the frame of a tribological research project we made a practical investigation how to machine the cast polyamide 6 (magnesium catalytic version) to achieve more advantageous machinability and surface properties, because the cast polyamide 6 is a basic, strategic engineering polymer.
Keywords: -.
FRICTION RESEARCH OF POLYMER GEARS
Gábor Kalácska, Róbert Keresztes, László Zsidai, Patrick DeBaets
Abstract: Technical polymers are widespread in the machinery owing to their beneficial properties against metals as operation without lubrication, low friction and wear, light weight, corrosion resistance, low manufacturing costs etc. There are many sorts of technical polymers available of which sliding elements can be produced.
To choose proper polymers for a given tribological application is not a simple task owing to many different parameters influencing the performance of a polymer sliding element. We launched a broad research project to clarify the friction and wear phenomena of plastic gears. With this presentation we introduce the newly developed measuring system for studying the friction process between the meshing gears.
Keywords: -.
NON-DESTRUCTIVE TESTING OF DRILLING OIL AND GAS EQUIPMENT AND TOOLS
Oleg Karpash, Maksym Karpash, Petro Krynychnyj
Abstract: One of the most effective ways of preventing drill equipment (pipe strings) failures is the evaluation of real technical state of threaded joints at various exploitation stages using methods of non-destructive testing. Detection of cracks in pipe body is reviewed. The parameters of inspection are determined for various standard sizes of pipes. Flaw detection in pipe threaded joints with triangular and tool-joints threads is discussed. The ultrasonic method is proposed to use. The special techniques of non-destructive testing are described. The most interesting is technique that allows flaw detection in heavy-weight drill pipes threaded joint without disassembling. Also a novel technique for quality inspection of thread stripping (bonding strength and leakproofness) is proposed. Theoretical basis of this technique is discussed. All techniques are implemented in real technical means that are showed and mentioned.
Keywords: non-destructive testing, ultrasonic, drilling equipment, pipes.
ACCURACY DETERMINING OF PLASTIC FORMING TOOLS WITH USING OF COORDINATE MEASURING MACHINE
Tomasz KEDZIERSKI, Stanislaw LEGUTKO, Michal LEHMANN
Abstract: In the article, the possibility of application of Coordinate Measuring Machine in the plastic forming tools manufacturing process has been discussed. The application contains also cooperation of CMM system with CAD/CAM. The example of measurement of the forging matrix for valve elements has been presented. The practical aspects of CMM application in the projecting and manufacturing processes has been discussed, too.
Keywords: plastic forming, CAD/CAM, CMM.
VISUAL DISASSEMBLING TECHNOLOGICAL PROCEDURES
Marek KOČIŠKO, Peter BRÁZDA
Abstract: Visual disassembling technological procedure creation in practice accelerate operation connected with renewal of stale parts in constructional nodes a make possible to execute disassembling operations event to less experienced employees.
Keywords: Disassembly, Sysklass, technological procedures.
RESEARCH REGARDING THE LIGNITE AND ROCK EXCAVATION USING BUCKET WHEEL EXCAVATORS
I. Kovacs, M.S. Nan, I. Andras
Abstract: In this paper the results of experimental and theoretic research regarding the phenomena occurring in the rock and lignite cutting using bucket wheel excavator are presented. The invariant character of the specific cutting resistance is demonstrated, and the translation of laboratory test results at real scale is presented and exemplified on a concrete case.
Keywords: -.
THE MEASUREMENT OF FORCES IN TURNING OPERATIONS
Radoslav KREHEĽ, Linda GREGOVÁ
Abstract: This paper describes the development of a new concept of cutting tools using strain gages for the measurement of forces in turning operations. The report describes the development of a new way of production remote control and long-range diagnostics of the controlled subsystems with orientation on the data communication. The basic idea is the integration of the sensor within the tool shank, in order to obtain a system which is easy to use, easy to install and capable of transmitting data to the CNC through wireless equipment. In particular, the output signal of the measurement bridge is amplified and sent to an external data acquisition system by infra-red transmission.
Keywords: Tool Condition Monitoring, Turning, Cutting Force Measurement.
BAND-SHOE BRAKE FRICTION UNIT DEFORMATION
Yevstahyi I. Kryzhanivskyi, Bohdan D. Storozh, Roman Karpyk, Yaroslav B. Storozh
Abstract: The finite element method is used to optimize friction unit design parameters and study the influence of the friction unit deformation in the brake open state and at the beginning of braking upon the band-shoe brake efficiency.
Keywords: drawworks, band-shoe brake, friction unit, deformation, wearing, finite element model, friction shoe.
THE FRACTURE TOUGHNESS OF THE HARDENED CAD-WHEELS
Ye. I. Kryzhanivskyi, D.Petryna , Ye.Yu.Petryna ,O.Onystchuk
Abstract: The activity is devoted to increase of cylindrical cog-wheels of load-carrying transmissions reliability and longevity by hardening a lateral area them teethes with the developed method of vibrational-centrifugal hardening processing. On bases of theoretical-experimental researches of hardener dynamics centrifugal operation the method of surface hardening with an increased level of deformation energy of a material necessary equipment for high-duty hardening processing is developed. Their fracture toughness has been studied.
Keywords: fracture toughness, cad-wheel, hardening, deforming, vibrations, resistance.
LOGISTIC PROCESSES IN ENTERPRISES USING FLEXIBLE MACHINING SYSTEMS (FMS)
Stanislaw LEGUTKO, Anna MATUSIAK-SZARANIEC
Abstract: In the article, the logistic processes of deliverance, production, distribution and utilization have been presented. The factory under analysis is of the machine building branch. In particular, the production processes have been discussed, considering storage organization, transport units and work places.
Keywords: -.
IMPLEMENTING BUSINESS PROCESS REENGINEERING
Gabriela LOBONŢIU, Radu BIG
Abstract: To succeed – or even survive – in today’s global economy, companies must refocus and reorganize themselves around their core processes: the end-to-end sequences of tasks that create customer value. Business Process Reengineering (BPR) is one technique which is aimed for that particular task. The present paper addresses some aspects concerning a framework for Business Reengineering, organizational knowledge and the implementation of BPR.
Keywords: Business Process Reengineering, strategic intent, core competences, organizational knowledge.
ASPECTS REGARDING VIRTUAL MANUFACTURING FOR FLEXIBLE CELLS PRODUCTION
Mircea LOBONŢIU, Vlad DICIUC
Abstract: In this paper a few aspects regarding virtual manufacturing and an application for a flexible cell that complies with a production situation are being presented.
Keywords: virtual reality, virtual manufacturing, flexible cells production, modeling.
EXPERIMENTAL RESEARCH REGARDING THE SHELL-MILL – PIECE METAL CUTTING TRIBOSYSTEM ON NUMERICALLY CONTROLLED MACHINES
Mircea LOBONŢIU, Mircea HĂŞMĂŞAN, Daniel MUREŞAN
Abstract: The paper approaches the outcome of some experimental researches regarding the shell-mill – piece metal cutting tribosystem, under the technological conditions of processing on numerically controlled machine-tools. The experiments were industry oriented, having been conducted under fabrication technological conditions. After presenting the experimental conditions, the paper brings out the scientific data of the experiments, those related to the variation of the tool wear compared to the length of metal cutting, as well as the variation of the absorbed power and of roughness, compared to wear.
Keywords: metal cutting tribosystem, tool wear, roughness, power in metal cutting.
DEFINING TRANSMISSION FUNCTIONS AND PROPER FREQUENCIES OF DRILLING STRINGS
V. Moisyshyn, Z. Kulynyn
Abstract: In this article the methodology of defining proper frequencies; transmission functions and coefficients of drilling strings dynamics with vibroprotective and back-up centered devices is being offered.
Keywords: proper frequencies, drilling string transmission functions, dynamics coefficient, vibroprotective device, back-up centered device.
SHAPING OF THE THERMO GAS KINETIC TUBES OF THE STRIPED OR FINNED BAYONET TYPE IN TURBULENT CONDITIONS
Dan Motăntău Sârbu, Tiberiu Stanciu, Mihai Nagi
Abstract: In the paper the principles of shaping of the thermo gas kinetic tubes of the Bayonet type – stripped or finned – in turbulent conditions are presented. The paper also deals with the solving of the equations of the eddy and also deals with the viewing of the folders with the specialized Phoenics software.
Keywords: tube, heat, transfer, Field, exchanges.
SURFACE HARDENING OF STEEL AND CAST IRON TOOTHED GEARS BY PENCIL LASER
Petru Muntean, Rodica Muntean
Abstract: The paper presents the general theory of the thermic treatment of hardening through surface quenching of the steel and cast iron toothed gears by a pencil laser, the possibility of rendering the entire process on the computer, the power and speed relations of the laser for a surface quenching of a given depth, the determination of the beam`s oscillation, the method`s advantages compared to classic proceedings of surface hardening and the sketch of the first romanian installation for surface quenching through laser beam.
Keywords: hardening, surface quenching by pencil laser, tooth flank surface.
THE FABRICATION OF WORM-SHAFTS THROUGH EXTRUSION
Petru Muntean, Rodica Muntean
Abstract: The paper presents three methods of fabricating shaft-worms through extrusion: the direct extrusion with consistent lubrication, the direct extrusion through two dies, positioned one inside the other one and the hydrostatic extrusion. The first two methods are proposed by the authors and the third one is a popular method through which worm-shafts and toothed helical gears, as bar or tubes, can be fabricated, and then canted in length.
Keywords: worm-shafts, precision extrusion, small pressure of extrusion.
RESEARCH ON THE EFFECTS OF ELECTRICAL DISCHARGES THROUGH ROLLER BEARINGS
PART I
Ionut Nacu, Alecsandru Simion, Cristina Racocea, Cezar Racocea
Abstract: The present study examines the effects of electrical discharges into the rolling paths and the bearing rolling bodies. The number, the size and the shape of the craters, generated by the electrical discharges, have been microscopically analyzed in different lubrication conditions, while varying the power and the amperage of the discharging electrical current.
This study is essential as a very large part of the electrical rotative machines are withdrawn from usage due to the damage of their bearing components. Very frequently, the above issues are worsening by the power peaks which are a consequence of the function of electronic converters commanded through impulses. These effects are similar with the electrical discharges through bearings. The knowledge the causes and the analyze of the effects through laboratory tests lead to very useful information regarding the decrease or even eradication of these effects.
Keywords: Rolling bearings, electrical current, electrical discharges.
RESEARCH ON THE EFFECTS OF ELECTRICAL DISCHARGES THROUGH ROLLER BEARINGS
PART II – EXPERIMENTAL TESTS RESULTS
Ionut Nacu, Alecsandru Simion, Cristina Racocea, Cezar Racocea
Abstract: The present study examines the effects of electrical discharges into the rolling paths and the bearing rolling bodies. The number, the size and the shape of the craters, generated by the electrical discharges, have been microscopically analyzed in different lubrication conditions, while varying the power and the amperage of the discharging electrical current.
This study is essential as a very large part of the electrical rotative machines are withdrawn from usage due to the damage of their bearing components. Very frequently, the above issues are worsening by the power peaks which are a consequence of the function of electronic converters commanded through impulses. These effects are similar with the electrical discharges through bearings. Knowing the causes and to analyzing the effects through laboratory trials lead to very useful information’s regarding the decrease or even eradication of these effects.
Keywords: Rolling bearings, electrical current, electrical discharges.
ABOUT THE IMPLICATION OF THE REGENERATIVE ENERGY IN THE OPTIMIZATION OF THE LINEAR ACTUATORS
Vasile NASUI , Radu COTETIU, Mircea LOBONTIU, Miorita UNGUREANU, Gabor PAY
Abstract: The paper approaches a major problem in the functioning of the electro mechanic linear actuator son which depend this capacity in the transitory regime that is the effect of the regenerative energy. This is essential taking into account the technical and technological importance of the actuators in the intelligent flexible industrial systems of refinement. In the future the researches can continue for the development of new applications on other types of mechanical transmission using this method and different modular control laboratory. This research offers a new concept concerning the development of new systems of linear actuation and simulation using adding numerical programs and virtual instrumentation.
Keywords: the electro mechanic linear actuator, the intelligent flexible industrial systems, regenerative energy.
SOME ASPECTS REGARDING EFFICIENT MANAGEMENT
Negrila Cosmin
Abstract: The recent acceptations consider that the management presupposes: to obtain results by means of other persons assuming responsibilities for these results; to be oriented onto the environment; to make decisions aiming the completion of the economic unit; to trust in subordinates, giving them responsibilities in order to obtain the proposed results, and recognizing for them the possibility of doing mistakes and receiving positively their initiatives; to de – centralize the organizational system and to appreciate the employees depending on results obtained by each of them. So, the paper wants to put in light the basis of efficient management.
Keywords: -.
ADVANTAGES OF THE GROUP TECHNOLOGY THEORY IN MANUFACTURING
Jozef Novák-Marcinčin
Abstract: Group technology is the realization that many problems are similar, and that by grouping similar problems, a single solution can be found to a set of problems thus saving time and effort. Although the definition is quite broad, one usually relates group technology only to production applications. In production systems, group technology can be applied in different areas. For component design, it is clear that many components have a similar shape. Similar components, therefore, can be grouped into design families and a new design can be created by simply modifying an existing component design from the same family.
Keywords: group technology theory, CAPP systems.
VIRTUAL REALITY MODELING LANGUAGE APPLICATIONS IN DESIGN OF MANUFACTURING SYSTEMS
Jozef Novák-Marcinčin
Abstract: Virtual Reality Modelling Language (VRML) is description language, which belongs to a field Window on World virtual reality system. The file, which is in VRML format, can be interpreted by VRML explorer in three-dimensional scene. VRML was created with aim to represent virtual reality on Internet easier. Development of 3D graphic is connected with Silicon Graphic Corporation. VRML 2.0 is the file format for describing interactive 3D scenes and objects. It can be used in collaboration with www, can be used for 3D complex representations creating of scenes, products or VR applications VRML 2.0 enables represent static and animated objects too. Interesting application of VRML is in area of manufacturing systems presentation.
Keywords: virtual reality, virtual reality modeling language.
CALCULATIONS IN DESIGNING GRIPPING HEADS
Anton Palko, Juraj Smrček, Peter Tuleja
Abstract: The methodology of designing gripping heads – grippers is a guarantee of a systematic procedure of preparing an optimal design of a gripper for specified conditions. The calculation of decisive functional parts of the gripper is an inevitable step in the algorithm and its designing. The calculation procedures are part of the concept and principles of solution of the gripper as well as of the direct solution of its structure. The choice of computational procedures, methodology of calculation of the decisive functional parts of the gripper is a condition of operational reliability and safety of operation of the designed gripper in the conditions of its application. This presentation introduces the methodology and procedure of calculating the grippers with both bilateral and unilateral gripping with the emphasis on the final safety of the head.
Keywords: industrial robot, gripping head, gripper, grasping, grasping element, object of manipulation.
CONDITIONS FOR TOOTHING IN TWO-STAGE MULTI-OUTPUT TRANSMISSIONS
Ján Paško, Slavko Pavlenko, Jozef Haľko
Abstract: The paper deals with the necessary conditions which are to be satisfied when designing and constructing the two-stage multi-output transmissions. The issue is closely connected with the previous study on the transmissions.
Keywords: involute teeth, internal wheel, gearings, cycloidal teeth.
IMPACT OF SPUR-GEAR-HOB DIAMETER ON TOOTH PROFILE ACCURACY
Slavko Pavlenko, Jozef Haľko, Ján Paško
Abstract: The paper investigates the impact of a spur-gear-hob diameter on tooth profile accuracy of a workpiece. In the process of analysis, the vector method of notation of the screw surface of the cutter and flat sides of the rack, which represents the ideal profile, was used. The presented method enables to analyse the impact of non-precision adjustment of the milling head of the spur-gear-hob on tooth profile of the workpeace.
The obtained results can be used for designing of more precise methods of profiling, especially of high-duty assembled spur-gear-hob used for tooth system manufacturing.
Keywords: spur-gear-hob, profiling, precision, tools manufacturing.
APPLYING HYDROSTATIC LUBRICATION AT MECHANICAL FACE SEALS
Nicolae Popa, Constantin Onescu
Abstract: From the engineering point of view, the mechanical face seal has two main constituent parts: one of them is fixed by the shaft and it’s rotating at the same time with it and the second one is the stator, which is fixed in the carcass. The two parts together form the primary mechanical seal. They can be rigidly tied by their support, but most of the time they allow one of more liberty degrees. These ties represent one or more secondary mechanical seals and also elastic elements.
The optimization of a mechanical face seal means the satisfaction of two antagonistic conditions. One is trying to reduce to the minimum the leakages, even to make them vanish and also trying to limit the friction and the wear. The second one presumes that a lubrication normal operation of the HS, HD, THD, EHD and/or M surfaces is ensured.
This paper takes into consideration just the hydrostatic lubrication from the primary mechanical seal, along with the purpose to place at projectors disposal different relations for the functional parameters (the opening axial force, the loss debit).
Keywords: Face seals, hydrostatic lubrication, axial force, loss debit, pressure.
HARD AND DECORATIVE STONES PROCESSING WITH HIGH PRESSURE WATER JETS
Sorin Mihai RADU, Gabriel DOLEA , Gheorghe TOMA
Abstract: The study of dimensional stone cutting using water jets is one of the major fields of activity of the Hydromechanization team of the Department of Mining Equipment of the University of Petrosani. The paper presents the researches carried out in laboratory cutting of marble and other rocks in order to derive the laws, which are governing this process.
Keywords: hydromechanization, cutting, rocks, water jet.
THE MATHEMATICAL MODEL FOR THE INTERNAL WORM GEARING WHIT CYLINDRICAL WORM
Sándor RAVAI NAGY, Eugen PAY
Abstract: In this paper we present the mathematical model for an experimental driving whit small dimension and high transmission ratio. This driving is the internal worm gearing whit cylindrical worm.
Keywords: mathematical model, internal worm gearing whit cylindrical worm.
APPLYING RELIABILITY ANALYSIS METHODS TO SHEARER BIT CONSUMPTION ASSESSMENT
Sorina Stănilă, Stela Dinescu
Abstract: In this paper are presented the results obtained at bit consumption that equipped the working part at different utilized types of shearer in mining exploitation from Jiu Valley, Romania.
Keywords: bits, reliability, wear, shearer.
CONTRIBUTIONS TO ESTABLISH THE SCREENING OPERATING CONDITIONS IN THE CASE OF CRITICAL HUMIDITY MATERIAL
Dinu Stoicovici, Adriana Coteţiu, Miorita Ungureanu
Abstract: This paper presents some aspects regarding the choice of amplitude and frequency in order to obtain the most favourable vibration operating conditions in the case of screening critical humidity material using an experimental device conceived by the authors. The critical humidity material has its particles under 10mm nominal dimension that have humidity in between 5% – 14%. The results are compared with the amplitude and frequency that result from some diagrams used for normal material (with particles bigger than 10mm and with humidity under 5%, or upper 14%). The presented analyse is valid for screening building material with critical humidity.
Keywords: sieve amplitude and frequency; building material; critical humidity material.
THE NEED FOR A CIVIL SOCIETY IN MINING SECTOR
Daniel Lucian Surulescu, Daniel Boteanu, Stefan Troaca
Abstract: Amongst all the changes of the last decade in Jiu Valley’s mining activity, more and more obviously, it turned to be a necessity like the civil society to get involved in the complex process of reestablishing the environmental balance, after the diminishing of the mining sector.
Keywords: -.
RESEARCH, INOVATION AND TECHNOLOGY TRANSFER IN MINERAL INDUSTRY
Giorgio Teseleanu
Abstract: Mining produces three types of mineral commodities (metals, industrial minerals, and fuels) that all countries find essential for maintaining and improving their standards of living. Mining is a strategic industry because it provides critical needs in times of war or national emergency. Neither economy could not function without minerals nor the products made from them. In countries or regions where mining is concentrated, this industry plays an important role in the local economy. Mining faces nowadays major constraints due mainly to the scarcity of resources and its social and environmental impacts. Solving in a balanced way the conflict between positive effects on growth and development and the negative impacts on human being, communities and surrounding environment is the main driving factor towards technological improvement based on research and innovation.
Keywords: research, R&D, technology transfer , innovation, mining.
NECESSITY OF DYNAMIC MODEL CONSTRUCTION AND SIMULATION FOR THE SIZING OF STRUCTURES
Zsolt TIBA
Abstract: As the first in a series of lectures the article presents the problem of sizing procedures in mechanical engineering, which extends to determination of loadings and structure characteristics and determination of the loading amplitudes absolutely necessary for sizing to counter fatigue. The paper makes it clear that without dynamic tests (simulation), even in the case of the most accurate models unusable structures could be designed, which would only come to light during trial operation of the constructed equipment under operation.
Further parts of the article series present the dynamic models, then the simulation programmes based on these, and finally the process and result of a simulation test by means of a concrete example.
Keywords: sizing procedures, loadings characteristics, loading amplitudes.
ASSESMENT OF THE CORELATION ECONOMIC STRUCTURE – ENVIRONMENTAL BALANCE
Valer Ungur, M.I. Capotescu, F. Nicolae, M.L. Rudeanu
Abstract: Relationships between economic structures and ecological balance can be assessed by three criteria at least: resource consumption – reflected in the pressure exerted on the natural capital fund and stock; volume of polluting emissions – reflected in the quality of the environment; efficiency of economic activity – reflected in the financing capacity of ecological costs.
The paper endeavors thus to approach and analyze these important aspects, both from an economic and ecological point of view.
Keywords: -.
DYNAMICS BRAKING OF THE LIFT
Miorita UNGUREANU, Ioana TAŞCU
Abstract: In this paper it is presented an approaching method of the dynamic process regarding to the lift mechanic brake with friction wheel.
Keywords: lift, brake moment, generalize co-ordinates, generalize speeds, kinetic energy, and potential energy.
LOGISTICS IN INDUSTRIAL ACTIVITIES
Nicolae UNGUREANU, Ivan KURIC
Abstract: Paper present some concepts about the logistics applications in industrial activities. It’s presented the relationship between the industrial system and economic environment and a possible approach of management of logistic activities.
Keywords: logistics, industrial system, management.
INFLUENCE EVALUATION OF THE VIBROPROTECTIVE DEVICES PARAMETERS ON THE CRACK INCREASE IN THE DRILLING STRING
V. Vekeryk, V. Tyrlych
Abstract: This paper presents the influence evaluation of the vibroprotective devices parameter (VDP) on the fatigued crack increase in the drilling string section on the basis of developed mathematic model. It has been got the dependence for the stress intensity factor from the vibroprotective devices parameter as well as operating mode of the drilling string. It favors to prevent the accidents and determine the remaining life of the damaged element.
Keywords: drilling string, vibroprotective device, stress intensity factor.
DATA EXCHANGE COMPATIBILITY BETWEEN CAD/CAM SOFTWARE IN INTEGRATED DESIGN PROCESS FO THE TECHNICAL PRODUCT
Miron ZAPCIU, Dorel ANANIA , Dragos TILINA
Abstract: In order to have good compatibility between CAD/CAM software, actually are used formats like STEP or IGES. In this paper are explained the internal structure for neutral formats and the most significant recommendations about data transfer.
Keywords: 3D Models, Computer Aided Design, data transfer, native formats, neutral formats.