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Journal PROCEEDINGS IN MANUFACTURING SYSTEMS |
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ISSN 2343–7472 ISSN-L 2067-9238 |
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Journal PROCEEDINGS IN MANUFACTURING SYSTEMS
□ Volume 13, Issue 2, 2018 ·.........
Joško VALENTINČIČ, Luka SEVŠEK, Miha
PRIJATELJ, Izidor SABOTIN, Marko JERMAN, Andrej LEBAR, Towards production of microfeatures
on a custom-made stereolitographic DLP printer Tool
electrode wear at obtaining external cylindrical surfaces by electrical
discharge machining ·......... Mihail
BORDEANU, Gabriel FRUMUŞANU, Nicolae OANCEA, Graphical modeling of gear tooth
generating process with rack-shaped tool, aiming constant area of detached
chips ·......... Vidosav
MAJSTOROVIĆ, Srdjan ŽIVKOVIĆ, ·......... Aurelian
ZAPCIU, George CONSTANTIN, Diana POPESCU, ........... Elastomer overmolding over
rigid 3D-printed parts for rapid prototypes ·......... Andrei
Mario IVAN, Radu Constantin PARPALĂ, Cezara Georgia COMAN, ........... Analysis of robotic
machining operations using a radially compliant end-effector pp. 51-55 Towards production of
microfeatures on a custom-made stereolitographic DLP printer Joško VALENTINČIČ1, Luka SEVŠEK2, Miha
PRIJATELJ3, Izidor SABOTIN4, Marko JERMAN5, Andrej LEBAR6 1) PhD., Assoc. Prof., Head of department, Faculty of Mechanical
Engineering, University of Ljubljana, Slovenia 2) PhD., Assistant, Faculty of Mechanical Engineering, University of
Ljubljana, Slovenia 3) M.Sc., Faculty of Mechanical Engineering, University of Ljubljana,
Slovenia 4) PhD., Assistant, Faculty of Mechanical Engineering, University of
Ljubljana, Slovenia 5) PhD., Researcher, Prof., Faculty of Mechanical Engineering,
University of Ljubljana, Slovenia 6) PhD., Assist. Prof., Faculty of Mechanical Engineering and Faculty of
Health Sciences, University of Ljubljana, Slovenia Abstract: Stereolithographic digital light processing (DLP)
printing is a liquid-based additive manufacturing process, where 3D parts are
made by curing a photosensitive polymer kept in vat. In this paper, the
in-house DLP printer is presented. It uses two spindles for coarse and fine
positioning in z-axis. A printer resolution is determined by printing
inclined channels of different depths. At this development level the
resolution is below 100 µm and it is to be further improved. Suitable process
parameters are determined, a micromixer is manufactured
and compared to the micromixer produced by casting. Better machining results
are obtained by printing, but casting is more suitable for large scale
production. Key words:
Additive manufacturing, DLP stereolithography, micromixer. pp. 57-62 Tool electrode wear at obtaining external
cylindrical surfaces by electrical discharge machining Laurențiu
SLĂTINEANU1, Ciprian MIRCESCU2, Margareta COTEȚĂ3,
Oana DODUN4,*, Gheorghe NAGÎȚ5, Adriana MUNTEANU6 1) Professor,
PhD, Department of Machine Manufacturing Technology, "Gheorghe
Asachi" Technical University of Iaşi, Romania 2) PhD student,
Department of Machine Manufacturing Technology, "Gheorghe Asachi"
Technical University of Iaşi, Romania 3) Lecturer,
PhD, Department of Machine Manufacturing Technology, "Gheorghe
Asachi" Technical University of Iaşi, Romania 4) Professor,
PhD, Department of Machine Manufacturing Technology, "Gheorghe
Asachi" Technical University of Iaşi, Romania 5) Professor,
PhD, Department of Machine Manufacturing Technology, "Gheorghe
Asachi" Technical University of Iaşi, Romania 6) Associate
Professor, PhD, Department of Machine Tools, "Gheorghe Asachi"
Technical University of Iaşi, Romania Abstract:
The electrical discharge machining is a method that could be applied
to obtain cylindrical external surfaces, inclusively by using tube type tool
electrodes. To diminish the shape errors due to the presence of the metallic
electroconductive particles detached from the two electrodes in the work
zone, a machining scheme based on the achieving of the vertical work movement
by the workpiece from up to down was preferred. An experimental research in
accordance with the requirements of a full factorial experiment with three
independent variables at two variation levels was performed. As independent
variables, the pulse on time, pulse off time and peak current were
considered, while as process output parameters the tool electrode massic and
linear wear were determined. Empirical mathematical models were established
and they highlighted the stronger influence exerted by the peak current
intensity. The correlation coefficient was calculated also for the values
obtained by the two distinct ways of evaluating the tool electrode wear. Key words: ram
electrical discharge machining, machining scheme, tool electrode wear, massic
wear, linear wear, empirical mathematical model, correlation coefficient. pp. 63-68 Graphical modeling of gear tooth generating process
with rack-shaped tool aiming constant area of detached chips Mihail
BORDEANU1, Gabriel FRUMUŞANU2,*, Nicolae OANCEA3 1) PhD Student, Manufacturing Engineering Department,
"Dunărea de Jos" University of Galaţi, Romania 2), 3) Prof., PhD, Manufacturing Engineering Department,
"Dunărea de Jos" University of Galaţi, Romania Abstract:
The process of machining with rack shaped tool the cylindrical
involute gears is commonly performed on MAAG machine tools, having wide
applications in practice. Despite this process is fundamentally rigorous, at the
same time it is characterized by a large variation of detached chip area,
which negatively influences the toothing process productivity. This paper
addresses the case of gear teeth generating with a multi-tooth rack-shaped
tool, approached on the base of CATIA graphical modeling. It is proposed a
modification of the rolling process, taking part between the centrodes
attached to both workpiece and tool, such as the sum of the chips areas that
are simultaneously detached by tool teeth at each stroke becomes
quasi-constant. Thereby, a variation law for workpiece circular feed is
determined, without altering the rolling condition, which would have as
consequence the unwanted modification of generated teeth profile. This type
of feed variation law can be implemented on NC machine tools of newest
generation, provided with the possibility of driving the rolling kinematical
chain with non-uniform, adjustable speed. Key words: gear tooth
machining, rack shaped tool, uniform area of detached chip, circular feed variation
law, graphical modeling. pp. 69-74 Cyber-physical manufacturing metrology
model (CPM3) approach in modeling milling and geometric inspection
of turbine blades Vidosav MAJSTOROVIĆ1,*, Srdjan
ŽIVKOVIĆ2 1) PhD, Prof., Mechanical Engineering
Faculty, Laboratory for Production Metrology and TQM, University of Belgrade,
Serbia 2) PhD, Experimental Aerodynamics
Division, Prototype Production Department, Military Technical Institute
Belgrade, Serbia Abstract: One of the key elements of digital manufacturing is
a simulation i.e. virtual modelling of all processes that belong to the
manufacturing value chain. This paper aims at estimating the surface deviation
error in the free form surfaces machining error and estimate the effect on
quality of the measuring process. A set of virtual experiments was designed
by applying the central composite design approach of response surface
methodology. The first set of virtual experiments determined the optimum tool
path strategy. The second set of virtual experiment optimization inspection
parameter to achieve maximum measuring accuracy and minimum measuring time.
Fully developed methodology was applied to mold turbine blade. Key
words: virtual
optimization, sculptured surface, manufacturing, inspection, digital
manufacturing, response surface methodology, mathematical modelling. pp. 75-80 Elastomer overmolding over rigid
3D-printed parts for rapid prototypes Aurelian ZAPCIU1,*, George CONSTANTIN2,
Diana POPESCU3 1) PhD Student, Machines and
Manufacturing Systems Department, University "Politehnica" of
Bucharest 2) Prof., PhD, Eng., Machines and
Manufacturing Systems Department, University "Politehnica" of
Bucharest 3) Prof., PhD, Eng., Machines and
Manufacturing Systems Department, University "Politehnica" of
Bucharest Abstract: Product designers and engineers can benefit from the
rapid production of prototypes with characteristics that closely resemble
those of finished products. In the
case of plastic objects which include rubber-like surfaces, existing manufacturing
options are either expensive or are impractical, limiting their use of rapid
prototypes. This paper presents a method of fabricating rapid prototypes by
combining rigid and soft materials through an overmolding process, thus
providing a fast and cheap way to obtain feedback regarding form-and-feel
characteristics during the design process. Functional objects can be also
produced using the proposed method, enhancing part design freedom. Elastomers
are injected or cast into molds attached to 3D-printed rigid parts in order
to form functional soft surfaces. Several solutions of binding elastomer to
parts fabricated using Fused Filament Deposition (FDM) are presented,
including multiple ways to produce the bonding of materials. Chemical bonding
and mechanical bonding using specifically designed geometries or exploiting
the interior structure of 3D-printed parts are proposed. Objects made from
rigid plastics overmolded with elastomers are produced for exemplification. A
time and cost analysis is also included as reference and for comparison with
other manufacturing methods. Keywords:
3D
Printing, prototyping, form and feel, elastomer, overmolding. pp. 81-91 Analysis of robotic machining
operations using a radially compliant end-effector Andrei Mario IVAN1,*, Radu Constantin
PARPALĂ2, Cezara Georgia COMAN3 1) 2) 3) Lect. PhD. eng., MSP department,
Politehnica Univeristy of Bucharest, Romania Abstract: This paper presents a comparative analysis conducted
by the authors in the field of robotic machining. The scope of the analysis
was to compare light machining operations performed on various materials
using an articulated-arm industrial robot equipped with a radially compliant
end-effector. Thus, the experimental procedures were conducted on aluminium,
wood and plastic. The approached machining operations were milling,
chamfering and surface finishing. The goal of the research was to determine
the values of the machining forces and to evaluate the influence of the
end-effector compliance on machining results. The approach chosen for the
experimental procedures was having the workpiece clamped on a dynamometer by
using modular fixturing components. The equipment used for experimental
purposes consisted of a six DOF articulated arm Kawasaki FS10E industrial
robot with 10 kg. payload and a Kistler 9257B dynamometer for measuring the
machining forces on three orthogonal directions corresponding to X, Y and Z
axes of the part coordinate system. The robot was equipped with an ATI RC-340
radially compliant deburring tool. The robot programming method used during
the experimental procedure was point to point block teaching using the teach
pendant. The results were observed both visually and through the results
shown by the Kistler dynamometer interface. Key
words: robotic
milling, machining forces, chamfering, surface finishing, dynamometer, force
measurement. Electronic mail: orgcom@icmas.eu |
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