Volume 9, Issue 4, 2014/Journal Proceedings in Manufacturing Systems

Abstract: One of the most used processes of the severe plastic deformation is the cold deformation process in the conventional ECAP die. Since it is a process with low productivity it is mainly used in laboratories for SPD testing. Starting from the severe plastic deformation process in conventional ECAP die, a new method was realized that allows the realization of this process in better conditions, with low friction. The work piece is 10´10 mm square section. The mobile part of the die is in contact with three of the four surfaces of the work piece. Only one surface of the work piece is in direct contact with the fixed part of the ECAP die that leads to reduced friction forces during plastic deformation. The objective of this paper is to perform a thorough analysis based on numerical simulation methods of the SPD process in the ECAP die with low friction applied on a work piece of aluminum alloy ENAW 6082. At the same time, it is aimed the way in which the plastic deformations are produced and the solution obtained analytically is compared with that obtained numerically. Also, the influence of the die geometrical configuration on effective strain, effective stresses (Von Mises), applied force, and influence of the friction coefficient on the applied force for the same geometrical configuration of the die were pursued.

Key words: numerical simulation, low friction ECAP die, SPD, aluminum alloy ENAW 6082.

pp. 199-204

3D SURFACE MODELLING ASPECTS FOR 3D PRINTING
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Aurel ARION¹, Tiberiu DOBRESCU^2,*, Nicoleta-Elisabeta PASCU³

¹⁾ Assistant, Engineering Graphics and Industrial Design Dpt., University “Politehnica” of Bucharest, Bucharest, Romania

²⁾ Professor, PhD, Machine and Manufacturing Systems Dpt., University “Politehnica” of Bucharest, Bucharest, Romania

³⁾ Lecturer, PhD, Engineering Graphics and Industrial Design Dpt., University “Politehnica” of Bucharest, Bucharest, Romania

Abstract: The "Rapid Prototyping" term does not include all recent applications of this technology but represents the principles of additive manufacturing process. Additive manufacturing is a process through which a solid object of any shape is created, starting from a 3D virtual model, by adding successive layers of material in a horizontal plane. The article is divided into six parts describing: the 3D printing process, geometric modeling of the objects relating to the 3D surface type, equipments, materials used in 3D printing, conversion of files and experimental results. A study on 3D printable geometrical surfaces through the material extrusion process is included in the present article. The 3D surfaces were modeled using different modeling applications, design software and an application for digital animation software. The five types of 3D surfaces are: NURBS surface, POLY surface, SUBDIVS surface, SOLID object and MASH surface. The objects have been printed on a 3D “Ultimaker –2” printer. Polylactic Acid filament was used to print the objects. The article also refers to 3D design and printing constraints generated by the machine work load limitations and the extruded material.

Key words: 3D printing, FDM, modeling, extrusion, geometry.

pp. 205-214

OPTIMIZATION APPROACH FOR MULTI-LAYOUT CONTINUOUS CASTED BILLET STORAGE AND INSPECTION WAREHOUSE
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Tudor-George ALEXANDRU^1,*, Doru ULMEANU², Georgia-Cezara AVRAM³

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

²⁾ MSc-Eng., Tenaris Silcotub S.A., Călărași, Romania

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

Abstract: In the present work, we propose an interactive approach for multi-layout electric steelwork shops expedition areas where casted round billets are stored in order to be cooled, inspected and loaded into means of transportation to be sent to the beneficiary. Even though this study was made referencing an electric steelwork shop in southern-Romania, the approach is universally available for multi-layout continuous casting billet warehouses where billets are handled using yard cranes or overhead bridge cranes. From an analytical standpoint, we use Arena Simulation to model the discrete event logistic system where entity flow through the system is described using a Poisson distribution and processes cycle time is described using a Normal (Gaussian) distribution. First of all, our study focuses on the optimal crane configuration or maximal number of billets to be handled to ensure a balance between the crane's cycle and process waiting time. From this end, having as input data the current steel mix and the demands for the length of the cut bars, a proper storage location logistics is explained based on the crane's travelling time and the number of cycles required to unload different configurations of billets. Finally, for proper production scheduling based on expedition priorities, a dimensional analysis model is presented where two total crane travelling distance formulas are derived. Using this model, complete cycle time can be predicted for any storage location. This approach made an overall improvement potential of 10% of the shipped output capacity for our reference case study.

Key words: Discrete event logistic system, normal distribution, Poisson distribution, process analyzer, storage location logistics, complete cycle time prediction.

pp. 215-220

VIRTUAL COMMISSIONING AS A FINAL STEP IN DIGITAL VALIDATION OF THE ROBOTIC MANUFACTURING SYSTEMS
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Adrian DUMITRAȘCU^1,*, Laurențiu NAE², Nicolae PREDINCEA³

¹⁾ PhD Student, Eng., PLM Consultant, ADA Computers, Bucharest, Romania

²⁾ PhD, Eng., Sales Director, ADA Computers, Bucharest, Romania

³⁾ PhD, Eng., Prof., Machines and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

Abstract: The Virtual Commissioning (VC) concept is the final phase in develop and simulate the robotic manufacturing systems which, together with all other benefits, allows companies to have a more efficient handling of the complexity in robotic assembly systems, a great decrease of the plant start-up time, and a resulting shortening of the product’s time to market. This paper presents the VC concept and all the resources and technology involved in development of a robotic manufacturing system and an environment setup proposition. The complete workflow of the virtual validation of the system is presented, and the implementation requirements and specifications are discussed.

Key words: Virtual commissioning, simulation, robot, process simulate, digital manufacturing.

pp. 221-226

GEOMETRIC ERRORS ANALYSIS IN MACHINING ON CNC MACHINE TOOLS

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Constantin SANDU^1,*, Adrian GHIONEA², Costin SANDU³, Ionuţ GHIONEA⁴

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

²⁾ Prof., PhD, Machines and Manufacturing Systems Department, University Politehnica of Bucharest, Romania

³⁾ Eng., Freedom Innovations, Irvine, Orange Country, California State, USA

⁴⁾ Lecturer, PhD, Machine Manufacturing Technology Department, University Politehnica of Bucharest, Romania

Abstract: In this paper the geometric volumetric accuracy of the machine tools is defined. A NC milling machine with three axes X, Y, Z is considered and a methodology is proposed for evaluating the geometric accuracy, important in the precise processing of parts. The application is based on the structure of a vertical milling machine, configured on computer. The deviations from the evaluation are useful in correcting the part NC program to control the machine tool. The geometric analysis of the machine tool is performed using components and assemblies that provide displacements in the three motion directions. For displacements, besides the deviations in the movement direction, spatial deviations exist. In each displacement direction, three deviations are defined for linear positioning d_x, d_y, d_z and the roll, pitch and yaw errors, e_x, e_y,e_z. Finally, based on the determined values, it is presented how these deviations are applied to implement corrections in part NC program.

Key words: linear displacement, pitch, roll, geometric errors, volumetric accuracy, NC program, computer program.

pp. 227-232

BALANCING OF PRODUCTION LINE USING DISCRETE EVENT SIMULATION MODEL

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Elena-Iuliana GINGU (BOTEANU)^1,*, Miron ZAPCIU², Mihai SINDILE³

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

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

³⁾ PhD Student, Machines and Manufacturing Systems Department, University “Politehnica” of Bucharest, Romania

Abstract: The paper is a central theme of research in the field of industrial engineering, which has as main objective the optimization of the flows in a flexible manufacturing system by configuring workstations required and the dynamic control of the rhythm and the manufacturing stocks based on modeling discrete event systems. The work presented in this paper is based on a real problem, with the purpose of optimizing and balancing a manufacturing line. In this article aspects of the whole production process are presented, which can be improved by using currently available equipment and software. Thus, a simulation using Delmia Quest software was introduced. Therefore, the topic of this paper is centred on material flow simulation and optimization. The objective of the simulation model was to determine bottleneck locations and to offer an alternative for improving the manufacturing line.

Key words: simulation, productivity, Delmia Quest, bottleneck, optimization.

pp. 233-238

METHOD AND INSTALLATION FOR RECYCLING PLASTIC WASTE AND TONER DUST IN THE PRODUCTION OF ASPHALT MIXTURES
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Simona Gheorghiţa ŞAŞCÎM (DUMITRESCU)^1,*, Costel Emil COTEŢ², Cicerone Laurenţiu POPA³, Gina STOICA⁴

¹) PhD Student, Machines and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

²) Associate Prof., PhD, Machines and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

³) Lecturer, PhD, Machines and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

⁴) Associate Prof., PhD, Machine Elements and Tribology, University "Politehnica" of Bucharest, Romania

Abstract: The waste management represents a significant issue worldwide that can be turned into an excellent opportunity for using the waste as raw materials in the processing industry, partially replacing the raw materials originated from natural resources. Plastic materials are products obtained almost entirely of petrol, and become a critical material in the modern world, being used for producing consumer goods in engineering or in constructions. It is strong, but this resilience makes it dangerous for the environment and thus, for people. Toner is used throughout campus in photocopiers and laser printers. The waste toner powder recycling presented a problem due to its complicated composition. This paper proposes changing of some current installations for producing asphalt mixtures and adapting it to the proposed technology for recycling the plastic waste and toner dust during the production processes of the asphalt mixtures.

Key words: waste plastic, Asphalt mixture, waste toner dust, road construction, recycling.

pp. 239-246

CAD-CAE IMPLEMENTATION IN CARGO SECURING SYSTEMS TESTING
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Ioan-Tiberiu GIURGIU^1,*, Petru ROȘCA², Iuliana-Florina PANĂ³

¹⁾ PhD student, Faculty of Engineering and Management of Technological Systems, University “Politehnica” of Bucharest, Romania

²⁾ Dipl. Engineer, Military Equipement and Technologies Research Agency, Clinceni, Romania

³⁾ PhD student, Military Equipement and Technologies Research Agency, Clinceni, Romania

Abstract: The paper presents a comparative analysis between numerical simulations performed in ANSYS software and the results obtained in real dynamic tests in order to observe the behavior of a cargo securing system. After a statistical analysis it can be noticed that the number of road casualties is higher when discussing about heavy goods vehicle (HGV) comparative to passenger vehicles. And one of the main reasons for accidents in traffic is the rollover effect caused by the incorrect securing of the load disposed on a truck platform. The subject of the analysis is a 6 ´ 6 military truck, adapted to carry onto its chassis a special platform, secured with atypical connections due to the complexity of the entire assembly. Both theoretical and practical information regarding the testing procedures are presented. The obtained results are also analyzed and the described methods could be useful for vehicle testing engineers in order to predict the possible failures during real testing.

Key words: cargo securing, FEM, braking, simulation, testing procedures, vehicle stability.

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