Abstract: Manufuture developed the Vision 2020, the Strategic Research Agenda and Road Maps as basics for the European Research in FP8. The vision was mainly influenced by the challenges toward competition and sustainability by transformation from cost orientation to adding value with technical and organizational innovations. Manufuture developed a strategic research Agenda “2020-2030” and Roadmaps to support the process of structural changes and orientation to higher efficiency and changeability. Technology development was driven by the activation of technological potentials in the process chains from basic materials to finished products and from customer’s orders to the end of life to increase adding value. Manufuture proposed fields of proactive actions for cooperative research in Europe across the 40 industrial sectors. Core fields of the strategic research agenda are part of the Factory of the Future (FOF) and Digital Manufacturing program and on the way now for implementation. Also in this analysis are include one example from Serbia about digital manufacturing concept..

Key words: manufature program, factory of the future, digital manufacturing, innovations.

pp. 9-18

PARAMETERS CONSTANCY − MUCH MORE IMPORTANT THAN THEIR VALUES

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Corneliu GORNIC

Director, Senior research engineer, PROFEX CONSULT SRL, Bucharest, Romania

Abstract: NIn techniques, in all branches (without exception, I think) the knowledge of a parameter, of a variable value would allow to take suitable measures for the negative influence compensation, diminishing of that one. If the considered parameter has an unforeseeable variation, evolution with sudden, random jumps it is hard to conceive that efficient compensation measures of its influence could be taken. On the contrary, if the error of that parameter, its deviation from a rated value is constant, or it is kept within statistic limits with a small 2σ, one could conceive efficient measuring and compensation measures. The paper is proposing to demonstrate that thing in the case of machine tools. It will be shown why some machine tools are accurate, but others in some limits, only. This paper is a continuation of a former one, referring to the bearing area..

Key words: machine tool, parameter constancy, accuracy, error compensation.

pp. 19-24

DEGRADATION OF THE SHAFT SURFACE DURING MACHINING TECHNOLOGY

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Luba HAJDUCHOVA, Frantiska PESLOVA, Jiri STODOLA

¹⁾ PhD, Research Worker, Faculty of Industrial Technologies, A. Dubcek University of Trencin, Slovak Republic

²⁾ Prof., PhD, Professor, Faculty of Mechanical Engineering, Czech Technical University, Prague, Czech Republic

³⁾ Prof., DrSc, Professor, Faculty of Military Technology, University of Defence, Brno, Czech Republic

Abstract: Estimation of structures life and ensure their safety and integrity is an essential part of the design of equipment for transport, engineering and other industries. Usually, fatal accident occurs often under varying loads without causing changes shape. Application of fracture mechanics and testing is possible to describe the propagation of cracks but the kinetics of damage in the early stages has not yet been expressed. The paper deals with identifying the causes of surface failure of a shaft made of material 42CrMoS4. On the basis of microstructural analysis completed by hardness testing, the occurrence of undesirable phases, such as non-metallic inclusions in the structure of the shaft, can be demonstrated. In the presence of various heterogeneous phases in the material structure, plucking of particles can occur during chip machining which leads to surface damage. In the conclusion, the authors recommend checking the starting material, which can eliminate problems that cause the degradation of the surface of the shaft. The failure of the surface causes the notch effect which initiates further failures of the material. Using highly sensitive methods for observing the surface such as scanning electron mikroskopy etc., unique data on mechanism of crack initiation were obtained. The authors present selected partial results of longitudinal studies that deal with failure mechanisms and surface materials and the formation of cracks.

Key words: chip machining, surface defects, non-metallic inclusions, microstructure, hardness, cracks.

pp. 25-30

SOLUTIONS FOR HYDRAULIC BALANCING OF THE POSITIONING AND FEED KINEMATIC CHAINS IN PORTAL MILLING MACHINES

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Dan PRODAN, Emilia BALAN, Anca BUCURESTEANU, George CONSTANTIN

¹⁾ Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

²⁾ Assoc. Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

³⁾ Assoc. Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

⁴⁾ Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

Abstract: The authors of this paper introduce hydraulic balancing systems for vertically moving heavy loads. The proposed system is suitable for heavy duty machine tools with crossrail that can be positioned depending on the size of the working piece. The positioning of the crossrail is relatively rare. Both crossrail and rail heads have big weights that can exceed 10-15 t. The entire weight of the assembly, friction and inertial forces are taken over by the positioning kinematic chain. In order to reduce the overall size and price of the kinematic chain elements, the solution is the crossrail balancing. The hydraulic balancing is made by means of two hydraulic cylinders symmetrically positioned. One shows the principle hydraulic diagrams, methodology of calculation and results of some simulations. For the crossrail balancing, a separate hydraulic unit for each of the two cylinders will be available. Experimental achievements are shown for a portal milling machine of FLP 2000 type. The specific feature of this system for crossrail balancing is that it uses the regular hydraulic equipment and having low prices. The hydraulic units for such balancing can successfully replace the complex and expensive units used for feed kinematic chains, in the case of CNC heavy duty machine tools. As well, the authors present a balancing hydraulic system for feed kinematic chains which is acting on crossrail heads of the heavy gantry machine tools, usually used for axes Z.

Key words: heavy machine tools portal type (gantry), positioning kinematic chain, feed kinematic chain, crossrail, crossrail heads, hydraulic balancing

pp. 31-40

GENERAL ALGORITHM FOR COMPONENT DESIGN-OPTIMIZATION FOR

MANUFACTURING EQUIPMENT CONSTRUCTION

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Alexandru BABĂ, Tatiana GEORGESCU, Aurel COSTEA

¹⁾ Lecturer, PhD, eng., Manufacturing and Industrial Management Department, University of Piteşti, Piteşti, Romania

²⁾ Assist. Prof., PhD Student, Eng., Manufacturing and Industrial Management Department, University of Piteşti, Piteşti, Romania

³⁾ Assoc. Prof. - Scientific Researcher II, PhD, Eng., Manufacturing and Industrial Management Department, University of Piteşti, Piteşti, Romania

Abstract: The modernization of manufacturing processes involves by all means the development and evolution of the technological processing, assembly and control equipment by developing new solutions in the field of blank and tool orientation and clamping, training, support, guidance, stiffening and transfer devices.Multi-criteria optimization of the technological system is determined by the complexity and dynamic character of its components, laying emphasis on its ability to adapt quickly and efficiently to the variety of the production tasks.

In our research we have developed and used mathematical models and optimization algorithms to design new structures and components for device, equipment and machine-tool construction and modernization. The systematic analysis of the optimization problems involved in the technological process and equipment is required by the need to highlight the multitude of factors and their interdependence with a view to establishing rational solutions in the field of manufacturing engineering. The optimization methods presented in this paper, from the optimization of blank surface orientation and clamping, the optimization of orientation and clamping device construction, the optimization of new structure development to the method of automatic generation of the manufacturing equipment structures are important steps in the complex optimization of the technological processes. As a systematic and objective approach of this paper, we have defined a general graph to describe the structures of the manufacturing equipment and an associated mathematical model used to optimize them.

Key words: parametric modelling, gear pump, constructive variants, FEM analysis.

pp. 41-46

IMPLEMENTATION OF HIGH CUTTING SPEED TECHNOLOGIES IN MACHINE TOOLS FOR INCREASING PRODUCT QUALITY

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Dorel ANANIA, Andra PENA, Cristina MOHORA

¹Lecturer, PhD, Machines and Manufacturing Systems Department, University Politehnica of Bucharest, Romania

¹Prof., PhD, Machines and Manufacturing Systems Department, University Politehnica of Bucharest, Romania

Abstract: In this paper some researches made for using high speed cutting technologies for machining parts on milling center are presented. The goal of this first study was to compare the roughing machining time for the same part by changing the cutting parameters based on the type of the tool trajectories. For cutting parameters calculation in classic theory, it is not taken into account the tool trajectories over the part surfaces. Another goal was to check the machine behavior for specific machining cutting conditions with high depth of cut and high cutting speed using an end mill tool for roughing procedure. The comparison was made between classic roughing with parallel trajectories and an innovative tool path programs implemented in Cimatron CAM software. The technique used is useful for machining small parts with cavities where high feed cutting tools cannot be used.nt.

Key words: high speed machining, machine tool, VoluMill, metal cutting.

pp. 47-52

MATERIALS AND TECHNOLOGIES USED IN PRESENT DENTAL IMPLANTS MANUFACTURING

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Sorin Mihai CROITORU , Ion N. MIHAILESCU, Ion Alexandru POPOVICI

¹⁾ Assoc.Prof. PhD, Machines and Manufacturing Systems Dept., POLITEHNICA University of Bucharest, ROMANIA

²⁾ Prof. PhD, Head of “Laser-Surface-Plasma Interactions” Laboratory, National Institute for Lasers, Plasma and Radiation Physics, Magurele, ROMANIA

³⁾ Lecturer PhD, Dentistry Faculty, University of Medicine and Pharmacy of Bucharest, ROMANIA

Abstract: Starting from 2008 the authors collaborated in several research projects, having the full support of the Romanian manufacturer of dental implants, Tehnomed Impex Co S.A. The aim of the research projects was to improve dental implants in order to better osseointegration. Studied materials used for base structure of the implants were both materials for medical purposes acquired from industrial manufacturers and new designed materials for human implants. Materials used for superficial layers of dental implants were studied in vivo, respecting ethical issues, but the research has to be continued. Manufacturing technologies for implants were classic metal cutting and sandblasting, while the technology used for superficial layers was Pulsed Laser Deposition. The paper presents a brief review of these materials and technologies, also presenting research results in some cases..

Key words: dental implants, titanium, zirconium, hydroxyapatite, βTCP, sandblasting, PLD

pp. 53-58

CONTRIBUTIONS TO POSITIONING ACCURACY DURING LINEAR MOTION OF CNC MACHINE TOOL TABLE

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Marius-Daniel PARASCHIV, Claudiu-Florinel BÎŞU, Miron ZAPCIU

¹⁾ Assist. Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

²⁾ Assoc. Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

³⁾ Prof., PhD, Machines and Production Systems Department, University “Politehnica” of Bucharest, Bucharest, Romania

Abstract: New evolution of machine tools involves various elements of artificial intelligence for workpiece in the best conditions of precision and quality. High geometrical precision is the main factor in achieving performance criteria. This requires certain onjectives: establishing a methodology for measuring positioning errors and ways to decrease them; establishing a methodology regarding the causes and prevention of errors; utilisation of a software error compensation and modifying CNC program using a CAM application; verification of the software efficiency by machining a workpiece without errors compensation, and machining a second one with processing paths improved. After performing these virtual operations, the workpiece was machined in order to verify the dimensional and form accuracy. Thus, it was used a software application, which we called it “Optimization of the numerical control”, which based on measurements of precision positioning,was used to optimize the coordinates of path processing, so that to increase the geometrical and dimensional accuracy of the workpiece. This program was checked by machining a test workpiece, resulting an important reduction of the finished piece dimensional errors. Thus, the main contribution, of this paper is that using the proposed approach the precision of CNC machine tools can be improved without the intervention upon the structural elements of the machine tool.

Key words: machine tool, geometric precision, error map, CNC program, error compensation software.

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