Abstract: Process planning is a group of instrumental actions to the achievement of the output of an operation’s system in accordance with a specified measure of effectiveness. It consists of devising, selecting and specifying processes, machine tools and other equipment to convert raw material into finished and assembled products. This paper presents an approach developed for supporting management at the earliest stage of manufacturing; in another words this approach which is called QCLPP (Quality, Cost, Lead time based Process Planning) is a toolkit for process planner to estimate manufacturing cost as well as manufacturing cycle time and product quality; using both QFD and FMEA tools to enhance life-cycle quality of ownership, this approach is also based on DFP to estimate the manufacturing cycle-time (time that elapses from work order release to completion) of a new product that will be made in a manufacturing system that makes other products as well. To estimate manufacturing cost and the cost of risks related to a process plan, ABC and CbFMEA are deployed in this approach. For each resource combination, the output data is gathered in a selection table that helps for detailed process planning in order to achieve higher level of efficiency. A software program has been developed; it aims at supporting process planner to achieve goals fixed by the company based on this approach. A case study is presented in order to illustrate the approach and prototype system in this paper.

Key words: ABC, DFP, QFD, FMEA, Lead-time, CAD/CAM, Manufacturing Cost.

pp. 15-24

DEVELOPMENT OF ASSEMBLY/DISASSEMBLY

PROCESS SIMULATION PLATFORM

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Robert IACOB, Diana POPESCU, Nicoleta CARUTASU

1, 2, 3) PhD, Lecturer, Machines and Production Systems Department, University “Politehnica” of Bucharest, Romania

Abstract: Nowadays, the design of a product cannot be made without considering the Assembly/Disassembly (A/D) process simulation required for reducing the time and cost of the different assembly stages: mounting operations for manufacturing, mounting and dismounting operations for replacing/repairing components/subassemblies, automated disassembly for product recycling at the end of its life. In this context, the current paper proposes a software platform for the complete analysis and simulation of the A/D process named VIPAD – Virtual Platform for A/D Simulation. The solution developed is based on a set of two new concepts: connection interface and mobility operator, which are used to detect the interfaces between components, to identify the fasteners from an assembly, respectively to calculate the components mobility, hence generating the valid disassembly trajectories of a component relative to its neighboring ones. The mobility of components is computed through a kinematical model able to represent all the valid movements of an element from an assembly: translation, rotation and helical movements. Thus, the proposed software solution will help designers to simplify their work in generating valid A/D plans by providing complete simulations starting from the 3D CAD model of the assembly product. A further consequence of the present work is the ability to generate models with semantic data attached. This supplementary information will improve the integration of the assembly models in immersive environments by taking into account the haptic and visualization data needed.

Key words: assembly/disassembly, design, simulation, connection interface, mobility operator.

pp. 25-28

CAI MODEL AND DIGITAL FACTORY

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Vidosav MAJSTOROVIĆ, Bojan ERČEVIĆ, Marko ERČEVIĆ, Igor ZUKAN

¹⁾ Prof., PhD, Mechanical Engineering Faculty, Belgrade, Serbia

²⁾ M.Sc., ”IVA 28”, Obrenovac, Serbia

³⁾ M.Sc., ”IVA 28”, Obrenovac, Serbia

⁴⁾ M.Sc., Mechanical Engineering Faculty, Belgrade, Serbia

Abstract: In on-line digital factory, all engineering activities are integrated and simulated before the real production process.``IVA 28`` is really good example of digital factory in our industry. This paper presents research, development and implementation of CAI-model, as a basic concept of the digital quality, in the concrete factory ``IVA 28`` from Obrenovac. Also, this paper presents computer integrated inspection and measurement in the final control of product quality. The slider is specific part that was measured on DEA measuring machine, and PC DMIS is used as software.

Key words: CAI, metrology, quality, PC DMIS, Digital.

pp. 29-34

CIRCULAR PATH FOR CNC MACHINE TOOLS

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Doina MARIN, Nicolae PREDINCEA

¹⁾ Scientific researcher, PhD, Robotics Department, Institute of Solid Mechanics of the Romanian Academy, Bucharest, Romania

²⁾ Prof., PhD, Machine and Manufacturing Systems Department, Polytechnic University of Bucharest, Romania

Abstract: Machine tools are built from many components and each component contributes motion error to the final tool tip position. There are multiple error origins including geometric, static and dynamic loading, thermal, mismatching between servo-loop parameters, interpolation etc. In the same time, the control of machine tools affects the accuracy of the work-piece. Therefore, in order to achieve high performances of feed drive system is required to analyses simultaneously both mechanical and control systems. To achieve high quality and productivity during continuous contouring, it is important to know how two axes work together. For this reason, to investigate the influence of the interactions on the system performance, circular tests are conducted. Results of the process make it possible to understand accurate dynamic behavior of a feed drive system.

Key words: feed drive system, contour errors, trajectory measurement, position control loop.

pp. 35-40

ADJUSTMENT OF VERTICAL LATHES ROTATIONAL

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Dan PRODAN1, Emilia BALAN, Anca BUCURESTEANU

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

Abstract: This paper presents some adjustment variants of vertical lathes main kinematic chain that have been used for more than 40 years and are still being used. These are presented comparatively by mentioning some values of adjustment ranges and torque couple necessary for the main kinematic chain. Initially, the gearboxes were built with sliding gears and couplings and they were used to decrease the rotational speeds in order to achieve the desired cutting speed. The rotational speeds decrease led indirectly to the amplification of the available torque. At the present moment, the vertical lathes CNC use modern gearboxes with planetary systems and frequency electronic converters which provide the decrease of rotational speeds and a proper amplification of torque output. At the same time, the number of steps of the gearboxes is reduced. The appearance of power transmissions with toothed belts had an important role in vertical lathes modernization. These improvements of the adjustment of main kinematic chain are necessary today, especially after numerical controls coming out, when the vertical lathes allow, besides turning, the machining of complex surfaces resulted from milling and grinding operations. In the end of the paper, there is presented an example of dynamic mathematical model for fixing the features of power and torque specific to vertical lathes CNC.

Key words: vertical lathes, gearbox, adjustment of rotational speeds, adjustment range, toothed belt power transmission.

pp. 41-46

CAD-CAE METHODOLOGY APPLIED TO ANALYSIS OF A GEAR PUMP

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Ionuţ GHIONEA, Adrian GHIONEA, George CONSTANTIN

¹⁾ PhD, Lecturer, Machine Building Technology Department, University “Politehnica” of Bucharest, Romania

^{2, 3)} PhD, Prof., Machines and Manufacturing Systems Department, University “Politehnica” of Bucharest, Romania

Abstract: The use of modern CAD and FEM techniques in the conception, simulation and manufacturing processes of industrial products has a large application in the mechanical, automotive and aerospace industry domains. This paper presents important aspects of a practical methodology applied to design a gear pump using the CATIA software parametric abilities followed by a FEM analysis of its assembly to identify the most stressed components. In the parametric design of the gear pump some of its constructive and functional data, among them, the flow being the main parameter, were taken into account.

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

pp. 47-52

THE ARCHITECTURE AND THE APPLICATIONS VISION OF THE EMBEDDED SYSTEMS AND BUSINESS INTELLIGENCE IN MODERN ENTERPRISE DEVELOPMENT STRATEGY

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Marius GURAN

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

Abstract: : Embedded systems (ES), as specialised devices for data processing and communication, are used in larger systems or machines, to control and add computing and communication capabilities to products, equipping them with new, very useful and exciting functions. In this way, they also add new value to traditional or existing goods. In this paper is defined the orientation in the area of embedded computer structures, nano-scale electronics, and software, that provide intelligence to products, processes, and services, and also are considered the applications vision for embedded systems and business intelligence. In this context are presented applications drivers for industrial systems, technology domains and challenges in assuming terms such as Business Intelligence (BI), Enterprise Resource Planning (ERP), Cloud Computing, and Software as a Service (SaaS), that are now part of the general vocabulary used when talking about modern enterprise.

Key words: embedded systems, intelligent systems and products, industrial embedded systems, applications in cloud computing, business intelligence.

pp. 53-58

STRESS STATES IN PLANE AND RIBBED CIRCULAR PLATES

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Carmen POPA, Radu IATAN, Ciprian MANESCU

¹⁾ Lecturer, PhD, eng., Department of Food Engineering, University Valahia, Targoviste, Romania

²⁾ Prof., PhD, eng., eng., University “Politehnica”, Bucharest, Romania

³⁾ Assist., PhD, eng., Inventiv SRL, Ploiesti, Romania

Abstract: Circular or annular plates and mostly ribbed structures have multiple utilizations in numerous engineering domains: processing equipments, naval, metallurgy, civil constructions industries. The engineering ability, implemented in practice, introduced to reduce the consuming of materials, but also the energy consuming, alternative solutions: materials for replacement or rigidifying using ribs. The topic of this paper takes into discussion the particular case of the structures with constructive orthotropy. In this paper is presented the analysis of stresses states for a plane and for a ribbed plate, to observe the advantage of the rigidifying. The presence of the ribs leads to reduce the consuming of metallic material. The plates, of the same dimensions, are solicited at 0.3 MPa pressure. For comparison, we used the analytical, finite elements and experimental methods for the plane plate and for the ribbed plate, we used the finite elements and experimental methods. In the technical literature, for the ribbed plate there is an analytical method for calculating of the deformation and stresses states, only some approximations for particular cases. Finally, as we infer from the comparison of the results, we observe the advantage of the rigidity of the plate. In this case the value of the stresses lower about three times. Closed values are obtained using the variants of calculus: analytical, finite elements and experimental. However, we note that at the embedded plates the maximum of stresses is located on the contour.

Key words: plane circular plate, circular plate with ribs, stresses states, numerical method, experimental method, analytical method.

pp. 59-64

PREDICTION OF CUTTING FORCE IN DRILLING UD-GFRP USING MATHEMATICAL MODEL

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Andra PENA^1,*, Claudiu BÎŞU²

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

²⁾ Lecturer PhD, Machines and Manufacturing Systems Department, University “Politehnica” of Bucharest, Romania

Abstract: Currently there is a strong trend to replace the metallic materials with composite materials, particularly polymer composites because of their superior properties, properties that can be designed and refined to meet specific requirements. Implementation of polymer matrix composite materials, especially those reinforced with glass fiber, is determined, including the obvious availability of raw materials used, and by the diversity of materials used for the matrix and reinforcing elements and the possibilities of combining their quantitatively and structurally. Glass fiber reinforced plastics (GFRPs) composite is considered to be an alternative to heavy exotic materials. Currently it is estimated that the reinforcement of polymeric materials with glass fiber has a 90% share in the global composites industry. Compared to metal alloys, composite materials have a better ratio mass -stiffness - resistance and reduced susceptibility to fatigue and corrosion. According to the need for accurate machining of composites has increased enormously. During machining, the obtaining cutting force is an important aspect. The present investigation deals with the study and development of a cutting force prediction model for the machining of unidirectional glass fiber reinforced plastics (UD-GFRP) composite using regression modeling. The process parameters considered include cutting speed, feed rate and depth of cut.

Key words: UD-GFRP, drilling, cutting forces, cutting tool, regression model.

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