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George CONSTANTIN
Adrian GHIONEA
Series Editorial Team
Emilia BĂLAN
Sorin Mihai CROITORU
Costel Emil COTEŢ
Editorial Council
Traian AURITE, Alain GERARD, Csaba GYENGE, Florin IONESCU,
Constantin ISPAS, Branko KATALINIK, Stanislav LEGUTKO,
Aurel OPREAN, Eugen PAY, Daniel PLAY
Bucharest, 2011
University “Politehnica” of Bucharest
Machines and Production Systems Department
Splaiul Independenţei 313, sector 6
060032 Bucureşti, România
Tel: (+4021) 402 94 20
E-mail: orgcom@icmas.eu
http://www.icmas.eu
Editura Academiei Române
Calea 13 Septembrie nr. 13, sector 5
050711 Bucureşti, România
Tel.: (4021) 318 81 46, (4021) 318 81 06, Fax: (4021) 318 24 44
E-mail: edacad@ear.ro
http://www.ear.ro
Peer reviewers: Aurel OPREAN, Alain GERARD, Daniel PLAY
Editorial assistant: Irina FILIP
Computerized editing: George CONSTANTIN, Mariana ŞERBĂNESCU
Gheorghe AMZA, Romania
Traian AURITE, Romania
Laurean BOGDAN, Romania
Octavian BOLOGA, Romania
Iooan BONDREA, Romania
Gheorghe BRABIE, Romania
Daniel BRUN-PICARD, France
Olivier CAHUC, France
Gavrilă CALEFARIU, Romania
Ilie CATANĂ, Romania
George CONSTANTIN, Romania
Radu COTEŢIU, Romania
George DOBRE, Romania
George DRĂGHICI, Romania
Gabriel FUMUŞANU, Romania
Alain GERARD, France
Adrian GHIONEA, Romania
Marius GURAN, Romania
Csaba GYENGE, Romania
Florin IONESCU, Germany
Sorin IONESCU, Romania
Mihaiela ILIESCU, Romania
Kostadin KOSTADINOV, Bulgaria
Ivan KURIC, Slovakia
Stanislav LEGUTKO, Poland
Nicolae MARINESCU, Romania
Josef NOVAK-MARCINCIN, Slovak Republic
Constantin MINCIU, Romania
Sevasti MITZI, Grece
Vasile NĂSUI, Romania
Tadeusy NIESZPOREK, Poland
Nicolae OANCEA, Romania
Viorel PĂUNOIU, Romania
Daniel PLAY, France
Nicolae PREDINCEA, Romania
Dan PRODAN, Romania
Ştefan Dan PASTRAMĂ, Romania
Tomasz RYDZKOWSKI, Poland
Jean François RIGAL, France
Ion SIMIONESCU, Romania
Laurenţiu SLĂTINEANU, Romania
Ştefan STAICU, Romania
Constantin STĂNCESCU, Romania
Eugen STRĂJESCU, Romania
Ioan TĂNASE, Romania
Miron ZAPCIU, Romania
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Journal
PROCEEDINGS
IN MANUFACTURING SYSTEMS
□ Volume7, Issue 1, 2012
·
Alexandru
EPUREANU, Gabriel FRUMUŞANU, Ionuţ CONSTANTIN, Florin Bogdan MARIN,
Machine tools control system – the new generation
·
Corina
CONSTANTIN,
George CONSTANTIN,
Aspects
regarding modelling the chip geometry in end milling
·
Sebastian Marius ROŞU, Marian Marius POPESCU, George DRĂGOI,
The enterprise IPSEC VPN solutions
·
Laurenţiu SLĂTINEANU, Oana DODUN, Margareta COTEAŢĂ, António
GONÇALVES-COELHO,
Irina
BEŞLIU (GRIGORAŞ), Lorelei GHERMAN, Maricela POIENARU,
A preliminary study on the rotational
molding process
·
Gábor László PÁY, Eugen PAY,
Special internal worm gear pairs with helical worm
·
Dan PRODAN, Anca BUCUREȘTEANU, Emilia BĂLAN,
Technical and economic considerations
on the purchase
of
a CNC machine-tool
·
Iuliana PISCAN, Thierry JANSSENS, Farid AL-BENDER, Cristina
PUPĂZĂ,
Experimental investigation of
tangential contact stiffness and equivalent damping
·
Adrian GHIONEA, George CONSTANTIN, George DOBRE, Gabriel Ionuț
GHIONEA,
Geometric and generation
particularities of the tooth with hypocycloidal curved flanks
The use of profitability index in
economic evaluation of industrial investment projects
Machine tools control system – the new generation
Alexandru EPUREANU1, Gabriel FRUMUŞANU2, Ionuţ CONSTANTIN3, Florin Bogdan MARIN
1)
Prof., PhD, Department of Manufacturing, Robotics and Welding
Engineering, “Dunărea de Jos” University of Galaţi, Romania
2)
Prof., PhD, Department of Manufacturing, Robotics and Welding
Engineering, “Dunărea de Jos” University of Galaţi, Romania
3)
Assist. Prof., Department of Manufacturing, Robotics and Welding
Engineering, “Dunărea de Jos” University of
4)
PhD., “Dunărea de Jos” University of
ASPECTS REGARDING MODELLING THE CHIP GEOMETRY IN END MILLING
Corina
CONSTANTIN1,*,
George CONSTANTIN2
1)
PhD Student, Machine and
Production Systems Department,
University “Politehnica“ of Bucharest, Romania
2) PhD, Prof, Machine and Production Systems Department, University “Politehnica“ of Bucharest, Romania
Abstract: Due to the fact that the milling process still remaining a challenge for researchers, the paper deals with the concept of chip geometry model built on the basis of geometric definition of the cutting tool, namely the inserts. This model type is considered for its integration into a global model of the cutting process. This research tries to give new methods for defining the uncut chip area and length, namely CAD methods, replacing the analytical ones very complex for some cutting tools. The main purpose of the work is to obtain functions of two variables (cutting depth and feed per tooth) for the uncut chip area, uncut chip length and uncut chip thickness using multiple regression algorithms. The achievement of the relation is important in cutting force estimation and also in optimization of cutting parameters. These functions of two variables (ap and fz) approximate the actual average chip area, length and thickness values with relative errors less than 10 %. The cutting tool used is CoroMill R 365-080Q27-S15M with cutting tool inserts R365-1505ZNE-PM 4230 (Sandvik Coromant). The fit between data obtained though CAD methods and data calculated through the model is very good, the functions for uncut chip area, length and thickness being reliable.
Key words:milling, milling cutter, insert, cutting edge curve, uncut chip area, uncut chip length, uncut chip thickness.
THE
Sebastian Marius ROŞU1,
Marian Marius POPESCU2, George DRĂGOI3,*
Liviu Mihail MATEESCU4, Ioana Raluca GUICĂ5
1)
PhD, Special Telecommunications Service, Radio Communications
Department,
2)
PhD Student, Special Telecommunications Service, Information Technology
Department,
3)
Prof., PhD, Faculty of Engineering in Foreign Languages,
University “Politehnica” of
4)
Lecturer, Economics Department,
University “Politehnica” of
PhD Student, Faculty of
Engineering in Foreign Languages,
University “Politehnica” of
Abstract: Now, in the 21st century, all enterprise have a local area network, a virtual private network, an Intranet and Internet, servers and workstations for operations, administration and management working together for the same objective: profits. Internet Protocol Security is a framework of open standards for ensuring private communications over public networks. It has become the most common network layer security control, typically used to create a virtual private network. This work analyses the network architecture for an enterprise geographically dispersed.
Key words: virtual enterprise, virtual enterprise network, IPSec, virtual teams, network architecture.
A PRELIMINARY STUDY ON THE ROTATIONAL MOLDING PROCESS
Laurenţiu SLĂTINEANU1,*, Oana DODUN2,
Margareta
COTEAŢĂ3,
António GONÇALVES-COELHO4,
Irina BEŞLIU (GRIGORAŞ)5, Lorelei GHERMAN6, Maricela
POIENARU7
1)
Prof., Department of Machine Manufacturing Technology, “Gheorghe Asachi”
Technical University of Iaşi, Romania
2)
Assoc. Prof., Department of
Machine Manufacturing Technology, “Gheorghe Asachi” Technical University of
Iaşi, Romania
3)
Lecturer, Department of Machine
Manufacturing Technology, “Gheorghe Asachi” Technical University of Iaşi,
Romania
4)
Assoc. Prof., UNIDEMI, Dep.to de Engenharia Mecânica e Industrial,
Universidade Nova de Lisboa, Portugal
5)
Junior Assist., Department of Mechanics and Technologies, University “Ştefan
cel Mare” of Suceava, Romania
6)
Eng., M.S. student, Department of Machine Manufacturing Technology,
“Gheorghe Asachi” Technical University of Iaşi, Romania
7)
Student, Department of Machine
Manufacturing Technology, “Gheorghe Asachi” Technical University of Iaşi,
Romania
Abstract:
The rotational molding is a
manufacturing method that allows obtaining parts with hollow form by
rotating a mold around two perpendicular axes with the part material in the
liquid state. Although the manufacturing method was proposed more than one
century ago, there are yet aspects less investigated and the emergence of
new materials that can be processed by rotational molding also generate
interesting problems for the researchers. The paper presents some
theoretical considerations concerning the conditions for the liquid flow
during the rotational molding process. The coordinates of a point belonging
to the mold were derived, even for the case where the mold rotates around
two perpendicular axes. By knowing the relations specific to the point
motion, the motion speed can be expressed. The main forces acting on a small
volume of liquid material, i.e., gravitational, viscous, and centrifugal
forces, were taken into consideration. The resultant force ensures
conditions for the penetration of the liquid material in the narrow spaces
of the mold cavity. A systemic analysis was used to highlight the main input
and output factors specific to the process.
Key words: rotational molding, liquid flow, motion trajectory, forces, systemic analysis, input factors, output factors.
SPECIAL
INTERNAL WORM GEAR PAIRS WITH HELLICAL WORM
View full
text
Gábor László PÁY1,*, Eugen PAY2
1
Prof. Ph.D., University College of Nyíregyháza, Hungary
2
Prof. emer. Dr.h.c., Ph.D., North University of baia Mare, Romania
Abstract:
The internal worm gear pairs are special ones, which are composed by a
helical worm and an internal teeth worm wheel. In the case of internal
worm gear pairs, when the internal teeth worm wheel are manufactured by
a worm hob with same geometrical parameters like the helical worm the
manufacturing not represent a difficult problem, especial in case if the
axis of worm and worm wheel are non perpendicular. .The paper presents
some aspects on construction models; on using special
devices; the mathematical modeling in the case of non perpendicular axes
and some aspects of manufacturing.
Key words: internal worm gears, helical worm, special devices.
TECHNICAL
Dan PRODAN1,*,
Anca BUCUREŞTEANU2,
Emilia BĂLAN3
1)
Prof.,
2)
Assoc. Prof.,
3)
Assoc. Prof.,
Abstract:
This paper introduces some aspects to be
taken into consideration when a company has to acquire a machine tool.
Money is a
precious asset and you need to spend it wisely when you have to repair an
aging piece of equipment, when you need to remanufacture components within
the unit or when it is necessary to replace equipment. The choice of the
machine tool type to be purchased depends on a number of factors also
related to production requirements, not only to machine price, such as: cost
of devices, tools, control
devices,
machining, cost of the possible
training courses, cost of necessary arrangements (foundation, electrical
connections, air, water, etc.), possible guarding and fencing of the
auxiliary spaces intended.
It insists
in particular on the purchase of heavy and very heavy duty machine tools
from the category of universal and
Key words: 3R policy, costs, technical & economic study, heavy duty machine tools, remanufactured machine tools, machine tools as an investment.
EXPERIMENTAL INVESTIGATION OF TANGENTIAL CONTACT STIFFNESS AND EQUIVALENT DAMPING
Iuliana PISCAN1,*,
Thierry JANSSENS2,
Farid AL-BENDER3,
Cristina PUPĂZĂ4
1)
PhD. ing., Department of
Machines and Production Systems, POLITEHNICA University of Bucharest ,
2)
Dr. ir., post-doctoral researcher, Department of Mechanical Engineering,
KU Leuven, 3001 Heverlee, Belgium
3)
Professor Dr. ir., Department of Mechanical Engineering, KU Leuven, 3001
Heverlee, Belgium
4)Associate
Professor, Dr.-Ing.,
Department of Machines and Production Systems, POLITEHNICA
Abstract:
In
this paper, the phenomena of hysteretic behaviour of frictional contacts
observed during reciprocating experiments are discussed. The hysteretic
behaviour is determined theoretically based on the expression of
hysteresis virgin curve. On the basis of the experimental analysis, an
analytical method for determining the energy dissipation, equivalent
damping and tangential contact stiffness is proposed. For all material
contacts the same tendencies of the energy dissipation and equivalent
damping can be observed which are increasing with load and displacement
and, also for the contact stiffness which is increasing with increasing
load and weakening with the displacement.
Key words:
contact stiffness, damping, hysteresis, friction, energy dissipation.
GEOMETRIC AND GENERATION PARTICILARITIES OF THE TOOTH WITH HYPOCYCLOIDAL CURVED FLANKS
Adrian GHIONEA1,*,
George CONSTANTIN2, George DOBRE3, Gabriel Ionuț
GHIONEA4
1)
Prof., PhD, Eng., Machines and Production Systems Department, University
“Politehnica” of Bucharest, Bucharest, Romania
2)
Prof., PhD, Eng., Machines and Production Systems Department, University
“Politehnica” of Bucharest, Bucharest, Romania
3)
Prof., PhD, Eng., Machine Elements and Tribology, Department, University
“Politehnica” of Bucharest, Bucharest, Romania
4)
Lecturer, PhD. Eng., Machine Building Technology
Department, University “Politehnica” of Bucharest, Bucharest, Romania
Abstract:
The hypocycloidal flanks
of the cylindrical gear teeth have the flank lines defined by lengthened or
shortened hypocycloid and the involute profile. The curved and bulged flanks
have some advantages, among them being the increased strength in bending and
controlled positioning of the contact imprint. The tooth flank generation
has on the basis the application of the technological process of milling
using a cutting tool with multi-cutters by rolling with mobile line and
continuous division. The paper deals with basic aspects regarding
kinematics, construction, and running of the multiple cutters milling head
for processing teeth with involute profile and hypocycloid at flanks in
cylindrical gears. The two curves that define the flank, the involute and
hypocycloid, are kinematically and simultaneously generated by rolling. The
cutting tool is constituted as an accessory adaptable on the tooth
processing machine of FD-Cugir type. The generated teeth are curved and
bulged presenting some qualities such as controlled positioning of the
contact zone, increase of bending resistance and so on. The gears processed
by means of the milling head had errors corresponding to the precision steps
8 and 9. The calculation relations and numerical data in the paper contain
the basic parameters that define the construction and the adjustment of the
tool, generation motions and geometry of the processed teeth.
Key words: multiple cutter milling head, cylindrical gear, curved flanks, closed hypocycloid, involute profile, adjust parameters, tooth processing machine, motion parameters, main motion, real cutting speed.ist 5-8 keywords.
THE USE OF PROFITABILITY INDEX IN ECONOMIC EVALUATION OF INDUSTRIAL INVESTMENT PROJECTS
Marian Andrei GURAU1,*
1)
PhD student, Faculty of Engineering and Technological Systems Management,
University “Politehnica” of
Abstract:
The economic and financial evaluation of
industrial investment projects in developed countries with market economy is
based on the combined use of traditional and modern, rational methods,
characterized by the scientific and reliability, tested and validated by
long practice. In this article is presented the indicator of economic
evaluation of industrial projects, profitability index, the method of
calculation, as well as the advantages and disadvantages of using it through
a case study. The case study shows a clear problem solving investment in
case of the existence of several variants of industrial projects and their
related modeling in linear terms. The profitability index is a significant
indicator in assessing the economic and financial performance of a project
or a company both internally and in the diagnostic tests requested by
external partners.
Key words: method of profitability index, economic evaluation, industrial investment projects.
Electronic mail: orgcom@icmas.eu /