pp.
3-8
View full text
PATH PLANNING FOR INSPECTION
PRISMATIC PARTS ON CMM AS A PART OF CYBER – PHYSICAL MANUFACTURING METROLOGY
MODEL
Vidosav MAJSTOROVIC1,*,
Slavenko STOJADINOVIC2, Numan DURAKBASA3
1) Professor, PhD, University of Belgrade, Faculty of Mechanical
Engineering, Department for Production Engineering, Belgrade, Serbia
2) PhD Student, Assistant Prof., University of Belgrade, Faculty of
Mechanical Engineering, Department for Production Engineering, Belgrade,
Serbia
3) Professor, PhD,Vienna University of Technology, Faculty of Mechanical
and Industrial Engineering, Department for Interchangeable Manufacturing and Industrial Metrology,
Vienna, Austria
Abstract: Cyber-Physical
System (CPS) are systems of collaborating computational entities which are in
intensive connection with the surrounding physical world and its on-going
processes, providing and using, at the same time, data-accessing and
data-processing services available on the internet. The essence of this research
is development Intelligent Model for Inspection Planning (IMIP) on CMM as
support of Cyber-Physical Manufacturing Metrology Model and its metrology
integration into coordinate measuring machine (CMM) inspection process
planning for prismatic parts. Presented model is advanced feature-based
inspection approach, whose advantage is in reduction the total measurement
time by reducing the time needed for the preparation of the measurements and
allowed opportunities for its optimization using one of the methods such as
swarm theory. Needed geometrical information for feature description is taken
from files IGES and STL. Output from the
IMIP is point-to-point measuring path without collision between measurement
probe and prismatic part. Distribution of measurement points for basic
geometrical features is performed on the base modifies Hamersley principle.
The results of the inspection of both PPs show that all tolerances are within
the specified limits. This confirms the efficiency of the proposed
feature-based model in IMIP of PPs. The model is especially suitable for use
in case of measuring path planning for geometrically complex PPs with large
numbers of tolerances.
Key words: Cyber-Physical
Manufacturing, Digital Quality, Path Planning, Prismatic Parts, CMM.
OPTIMIZATION OF
PROCESS PARAMETERS OF SURFACE GRINDING OPERATION USING TAGUCHI BASED GREY
RELATION ANALYSIS
Prashant J. Patil1,*,
Chandrakant R. Patil2
1) Eng,
Principal, Abhinav Education Society’s COET(P) Pune, India
2) Prof.
in Mech. Dept, Ram Meghe College of
Engg. and Management, Amravati, India
Abstract: Heat produced during the
grinding process is always critical in terms of workpiece quality. Effective
cooling and lubrication is necessary to control temperature levels.
Traditional cooling system has negative impact in terms of cost of recycling
and health hazard to machine operator. Most successful fluid reduction method
employed in grinding is minimum quantity lubrication (MQL). This study aims
for multi objective optimization of MQL grinding process parameters using
Grey relational analysis. Water based Al2O3 and CuO
nanofluids of various concentrations are used as lubricant for MQL system.
Experiments were performed using L27 orthogonal array on instrumented surface
grinding machine as per Taguchi’s method. The
process parameters that considered for optimization are feed rate, depth of
cut, type of lubricant, grinding wheel speed, coolant flow rate, and
nanoparticle size. Grinding performance is measured in terms of cutting force
and temperature of grinding zone. Analysis of variance (ANOVA) has been used
to identify most significant factor of the process.
Key words: CuO, Al2O3 nanofluids, MQL surface grinding,
tangential force, effective
thermal conductivity.
HEAT TRANSFER SIMULATION FOR
THERMAL MANAGEMENT OF ELECTRONIC COMPONENTS
Tudor-George ALEXANDRU1*,
Theodor-Adrian MANTEA2, Cristina PUPǍZǍ3,
Ştefan VELICU4
1) Eng., Machines and Manufacturing Systems Department, University
"Politehnica" of Bucharest, Romania
2) PhD Student, Machines and Manufacturing Systems Department,
University "Politehnica" of Bucharest, Romania
3, 4) Prof., PhD, Machines and Manufacturing Systems Department, University
"Politehnica" of Bucharest, Romania
Abstract:
The present research addresses electronics design issues with emphasis on the
heat transfer simulations. The first part comprises a brief introduction to
the electronics design workflow. The problem of the heat transfer is
discussed at all engineering levels. Due to the complexity of this problem,
multiphysics aspects remain in a close relationship with the thermal
management systems. Such issues place the heat transfer simulation as a
central design problem. Further decisions like economic, environmental,
ergonomic or performance aspects remain sensitive to the solution of the heat
transfer analyses. In the second part of the work, the heat transfer problem
statement is described. Engineering knowledge achievements and their
relationship with a PLM platform are schematically discussed. The most common
heat transfer solvers are presented and the simulation peculiarities for the
electronic components are emphasized. All this concepts are validated in the
third part of the work, where two case studies are presented. First, an
example of natural convection transfer for a heat sink was performed, in
order to define theoretical aspects regarding the heat sink evaluation and to
demonstrate how non-linear solvers based on the Finite Element Method can
assess the transient temperature behavior. The second study was an
experimental forced-convection steady-state cooling setup, simulated using
Computational Fluid Dynamics. Numerical and experimental results for this
simulation proved a good match. Concluding remarks were highlighted at the
end of the paper.
Key words: electronics, design, cooling, heat transfer, knowledge, FEM, CFD.
ELIMINATING THE BACKLASH OF
CIRCULAR FEED DRIVES OF CNC VERTICAL LATHES
Dan PRODAN1,*, Mișu
PETRE2, George CONSTANTIN3, Anca BUCUREȘTEANU4
1, 3, 4) Prof., PhD, Eng., Machines and Manufacturing
Systems Department, University “Politehnica” of Bucharest, Romania
2) Eng., Head of Design Department, Titan Heavy Machine Tools,
Bucharest, Romania
Abstract: Most
circular feed and/or positioning kinematic chains used in CNC machine tools
consist of: AC motor with speed adjustment through frequency, mechanical
gearbox and a final pinion-wheel mechanism type. All the above mechanisms
have functional backlashes that cumulated affect the positioning and
processing accuracy. The paper presents some specific issues regarding the
design, construction and operation of vertical lathes having such kinematic
chains. Different variants of anti-backlash devices used by companies
specialized in the production of vertical lathes are presented. Some
hydro-mechanical solutions using two pinions for the final gear mechanism are
presented in which the hydraulic unit is supplying the necessary torque that
force one pinion to work on one flanks of the wheel teeth and the other one
on opposite flanks. Some solutions with parallel pinion axes and also with
coaxial axes of pinions are presented. The article presents some patents used
in the field of cancelling backlash in final gears of feed drives of machine
tools. Also, the papers brings in discussion the solution with eliminating
backlash by using two pinions separately driven through two drives driven by
own electric motors working in the Master/Slave regime. The machines and solution of cancelling
100% of the backlash are belonging to the group of vertical lathes with
tables having diameters between 1250 mm and 20000 mm.
Key words: vertical lathe, backlash, anti-backlash designs, hydro-mechanical
systems, electrical systems.
A VISCOELASTIC MODEL
FOR SKIN OF STUMP IN TRANSTIBIAL PROSTHESIS
Robert FILEP1,
Dragos AROTĂRIȚEI2,*, Marius TURNEA3, Mihai
ILEA4, Mariana ROTARIU5, Cristian BUDACU6
1) PhD Student, OrtoProfil, Tg. Mures, Romania
2) Prof., PhD, University of Medicine and Pharmacy "Grigore T.
Popa", Iasi, Romania
3) Lecturer, PhD, University of Medicine and Pharmacy "Grigore T.
Popa", Iasi, Romania
4) Lecturer, PhD, University of Medicine and Pharmacy "Grigore T.
Popa", Iasi, Romania
5) Assistant Prof., PhD, University of Medicine and Pharmacy
"Grigore T. Popa", Iasi, Romania
6) Assistant Prof., PhD, University of Medicine and Pharmacy
"Grigore T. Popa", Iasi, Romania
Abstract: The
displacement of different parts during gait cycle as force and pressure
effect can contribute to developing and increasing of lesions. In present paper we investigate the
viscoelastic model for prosthetic skin using a rheological model, the Maxwell
slip model. We propose a Maxwell model for hysteretic
behavior of skin (force vs. displacement) at the interface of stump-socket in
transtibial prosthetic case. Various methods for parameter optimization in
the Maxwell model are discussed and a novel method is proposed: genetic
algorithm with multiple separated chromosomes in order to find the minimal
number of elasto-elements with maximum performance of model. The Force and
displacements are measured using Finite element model (FEM ) and simulations.
The experimental results of simulation take into account two different form
of hysteresis for two different locations on stump.
Key words: Hysteresis, Maxwell model, genetic algorithms, stump-liner and stump
socket interface, transtibial prosthesis, finite element model.
pp. 41-46
View
full text
MODERNIZATION OF COOLING
UNITS FOR TOOLS AND WORKPIECES IN MACHINE TOOLS
Anca BUCUREȘTEANU1,*,
Dan PRODAN1, Emilia BĂLAN2, Adrian MOTOMANCEA3
1) Prof., PhD, Eng., Machines and Production Systems Department,
Politehnica University, Bucharest, Romania
2) Assoc. Prof., PhD, Eng., Machines and Production Systems Department,
Politehnica University, Bucharest, Romania
3) Assoc. Prof., PhD, Eng., Mechanics Department, Politehnica
University, Bucharest, Romania
Abstract: This
paper presents some specific issues of the design and manufacturing of
cooling units for tools and workpieces in machine tools during the cutting
process. Besides the general theoretical aspects, adaptable to most of the
existing machine tools, the paper lays particular emphasis on the aspects
specific to modern machine tools (CNC ones), on which the machining
operations are performed with high speed cutting, in the case of serial or
mass production. Also this paper presents some of the simulations made in the
design phase of the unit. Using these
simulations one can check the behaviour of the unit before it being made,
avoiding choosing unapproved parts. The unit designed and manufactured is
intended for a milling machining centre with horizontal spindle, type MAXIM
11 and allows the cooling of the tool and workpiece by programmed control on
the outside of the tool but, where appropriate, through the inside of the
tool. The unit also allows the cooling with air or the blowing of the
tool-holder taper during the automatic changing of this one from the
tool-magazine. Now the unit manufactured for milling machining centre with
horizontal spindle of MAXIM 11 type is functional and did not raise operating
or maintenance problems for more than two years. Cooling on the outside of the tool is done with the machine working
at a maximum pressure of 10 bar. Cooling onside the inside of the tool is
done with the machine working at a pressure of 70‒75 bar, but during
commissioning it has also been tested at 90 bar.
Key words: machine tools, cooling unit, water emulsions, design, outside tool
cooling, inside tool cooling.
pp. 47-52
View
full text
INNOVATIVE EQUIPMENT FOR
IMPROVED COAL EXTRACTION TECHNOLOGY IN THICK SEAMS
Nicolae ILIAȘ1,
Iosif ANDRAȘ2,*, Sorin Mihai RADU3, Iosif GRUNEANȚU4, Aurelian SERAFINCEANU5
1, 3, 4, 5) Prof., PhD, University of Petroșani, Dept. Mechanical, Industrial and Transportation
Engineering, Petroșani, Romania
2) PhD., Eng, GEROM INTERNATIONAL S.A., Petroșani, Romania
Abstract: The
paper deals with a series of innovative solutions of equipment devised in
order to improve the efficiency of mechanized coal faces in thick seams which
avoids the inconveniences related to the effect of the increased face height
on the on shearer, armored face conveyor(AFC) and shield supports, by a new
concept of mechanized extraction complex. The presented system encompasses
some innovative constructive changes on the shearer, on the face conveyor and
shields, such as a new positioning of the shearer’s body and the drums
symmetrically related to its longitudinal axis, a new concept of AFC,
allowing the reduction of height and offering accessibility to chains
and flight bars and a new construction
of shield allowing the increase of operating height with a shortest canopy,
and offering a better kinematics in a wider range of working heights. The
proposed system is only a concept, the
refining of it being suitable for the construction of a new generation
of mechanized longwall faces with increased working height, with
relevant advantages in terms of
productivity.
Key words: mining equipment, coal extraction, mechanized longwall face, shearer,
AFC, support shield.