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KOMISJA BUDOWY MASZYN PAN – ODDZIAŁ W POZNANIU
Vol. 28 nr 1
Archiwum Technologii Maszyn i Automatyzacji
2008
PETER ŠUGÁR∗, JANA ŠUGÁROVÁ∗∗, LADISLAV MOROVIČ∗∗∗
THE SHAPE ACCURACY ANALYSIS OF MACHINE PARTS
PRODUCED BY METAL SPINNING
Metal spinning is old method reshaping materials, derived from the ancient Egyptian art of
potting on a wheel. Today, it is high-tech computerized manufacturing technology, which produces axisymmetric hollow parts with advantageous surface layer properties. Different spinning
methods result in different qualitative parameters of spun parts.
The paper presents the partial results of the experimental study, focused on the analysis of the
shape accuracy of parts (samples) produced by multi-pass metal spinning. For the experimental
study thin sheets with 1 mm thickness were used. The shape accuracy of the parts was analysed by
the optical 3D measuring machine based on the principle of triangulation (3D coordinates for each
camera pixel are calculated with high precision and a polygon mesh of the object’s surface is
generated). The 3D digitilizing with the mobile GOM ATOS I 350 system was used. For the
visualization of shape deviations of real forming parts compared to nominal shape was realised
using color plots.
Key words: spinning, shape, accuracy
1. INTRODUCTION
Forming is a manufacturing process, which plays the dominant role in the
nowadays competitive industry. One of the relatively old, but now high-tech
computerized forming technology is metal spinning, which produces axisymmetric hollow parts with advantageous surface layer properties (conventional spinning, shear spinning or tube spinning). The process can produce a wide variety
of shapes, providing unlimited opportunities for part designers as well as for new
applications.
Spinning, compared with deep drawing, involves lower forming forces and
less power. As a result, equipment is cost-effective engineered and process is
very flexible. Other benefits are: increased level of automation, high mechanical
∗
Assoc. Prof. PhD. MSc. Department of Manufacturing Technology and Material Science,
Technical University in Zvolen.
PhD. MSc.
∗∗∗
PhD. MSc. – Institute of Manufacturing Technologies, Slovak University of Technology in
Bratislava.
∗∗
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P. Šugár, J. Šugárová, L. Morovič
strength and hardness of part material, cost reduction by high material yield and
favorable cycle time. These benefits apply to production of one-offs and prototypes as well as to small to medium runs. Nowadays the process is getting increasing importance in many fields of industrial applications, as for example in
the manufacturing of process equipment such as centrifuges, funnels, tanks,
medical and gastronomy equipments as well as drive technologies. It also has the
possibility of producing parts that could not be deep drawn [3].
Benefits available for users of the spinning technology include: high
flexibility, increase level of automation, very low risk of crack propagation, high
mechanical strenght and hardness of spun parts, cost reduction through high
material yield, variety of operations possible in one setup and favorable cycle
time.
Principle of the conventional metal spinning proces shows Fig. 1.
Fig. 1. Principle of the metal spinning process: 1 – mandrel, 2 – follow block, 3 – blank, 4 – spinning
tool, 5 – tailstock centre
Rys. 1. Zasada procesu wyoblania – drykowania metali: 1 – wzornik (model), 2 – tarcza dociskowa,
3 – półwyrób (blacha), 4 – rolka do wyoblania, 5 – kieł mocujący
The experimental investigation of spinning parameters on the shape accuracy
of part formed by conventional (multi-pass) spinning technology was realised at
the Department of Manufacturing technology and Material Science, Faculty of
Environmental and Manufacturing Technology, Technical University in Zvolen
[1], [4], [5], [6]. The methodology and results of the spun parts shape accuracy
measure by optical 3D measuring machine, are presented in the paper.
The shape accuracy analysis of machine parts produced by metal spinning
139
2. SHAPE ACCURACY MEASUREMENT
METHODOLOGY OF EXPERIMENTS
A spherical shape of radius 107,5 mm blending via a 25 mm radius into a 168
mm diameter cylinder was used for these experiments (Fig. 2 and Table 1). Part
was made from thin steel sheet STN 41 1375.21 (EN 30-69) and STN 41 7240
(EN 10088/1-3-95), thickness s = 1 mm. The manual spinning lathe was used.
Variable parameters were spindle revolution (n = 315, 490 a 890 min–1) and
number of passes of spinning tool (spinning without sizing p = 3 and with sizing
p = 4).
Table 1
Mandrel’s dimensions
Rozmiary wzornika
D
h1
h2
r1
r2
168 ± 0,3
100
60
107,5
25
Fig. 2. Mandrel
Rys. 2. Wzornik (model)
The experimental samples were analysed from the shape accuracy point of
view. 3D digitalization of the metal spinning part shape was realized by the system of optical scanning GOM ATOS I 350 (Advanced Topometric Sensor), consisting of two CCD cameras (they are located in the way that objective lens form
an angle of 29 degrees) and projector (Fig. 3). The evaluation of computer models was realized by using of software GOM ATOS v. 6.0.2-5, which allows dimensional and shape deviations analysis of scanned forms in relation to nominal
data [2].
The basic aim of the experimental works was to consider the possibilities of
the 3D optical scanning application to handle the shape accuracy analysis of the
manufactured parts. The results of these works were processed in the visualization form of the part shape deviation and in the form of graphical surface deviation plots in a 3D presentation.
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P. Šugár, J. Šugárová, L. Morovič
Fig. 3. GOM ATOS I 350 optical measuring system
Rys. 3. GOM ATOS I 350 optyczny system pomiarowy
The Fig. 4 and Fig. 5 present the result of shape accuracy measurement of
parts made from material STN 41 7240 (EN 100088/1-3-95), thickness of sheet
was 1 mm, spindle revolution n = 890 min–1, number of passes p = 3 (multi-pass
spinning without sizing).
The comparison of surface deviations to the reference data for spinning with
and without sizing, for material STN 41 1375.21 (EN 30-69), are summarized in
Table 2.
Material: STN 41 7240, EN 10088/1-3-95
s = 1mm, n = 890 min-1, p = 3
Profil of spun part
Nominal profil
z
x
Fig. 4. Vizualization of real and nominal profile of spun part
Rys. 4. Wizualizacja rzeczywistego i nominalnego profilu elementu wyprodukowanego metodą
wyoblania
The shape accuracy analysis of machine parts produced by metal spinning
Material: STN 41 7240, EN 10088/1-3-95
s = 1mm, n = 890 min-1, p = 3
y
z
x
141
Real shape of spun
part
Nominal shape of spun part
Fig. 5. Vizualization of real and nominal 3D shape of spun part
Rys. 5. Trójwymiarowa wizualizacja rzeczywistego i nominalnego kształtu elementu wyprodukowanego metodą wyoblania
Table 2
Comparison of surface deviations for spinning with and without sizing
(material STN 41 1375.21 (EN 30-69), n = 890 min-1)
Porównywanie odchyłek kształtu elementu wyprodukowanego metodą wyoblania z następującym
potem kalibrowaniem oraz bez kalibrowania
Position of measure
[mm]
Surface deviation [mm]
Number of passes p = 3
(spinning without sizing)
Number of passes p = 4
(spinning with sizing)
Point 1 (–86,7; 6,4; –60,1)
+ 2,97
+ 1,81
Point 2 (–79,7; 2,9; –34,9)
+ 0,53
+ 0,30
Point 3 (–68,9; 4,9; –24,3)
+ 0,62
+ 0,53
Point 4 (–51,2; 6,4; –12,5)
+ 0,58
+ 0,25
Point 5 (–1,7; 11,7; –0,62)
+ 0,03
+ 0,00
3. CONCLUSIONS
Presented methodology and results are partial task of the research aimed at
complex evaluation of qualitative parameters of parts manufactured by the metal
spinning. The results of the shape accuracy analysis, obtained by 3D optical
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P. Šugár, J. Šugárová, L. Morovič
scanning method, show the factuality of the monitoring of selected process parameters impact (e.g. springback error) on the final shape accuracy.
Graphical outputs show a high degree of shape deviation in the places, which
are the furthest from the symmetry axis. In this case, the resulted state was
caused by the material properties and by the fact, that the manufacturing of the
parts was manual. By the using of a spinning roller operated by a hydraulic feeding mechanism, there is not expected such a wide difference between real and
nominal shape of the manufactured part.
REFERENCES
[1] Gašparová, J., Šugárová, J., Kalincová, D. Study of microstructure and formed part wall
thickness changes after metal spinning. In Development of Mechanical Engineering as a Tool
for Enterprise Logistic Progress. Poznan : ZPW M-DRUK, 2006, s. 187-192.
[2] GOM ATOS v. 5 – User Manual. Braunschweig, 2005.
[3] Palten H., Palten, D. Metal spinning – From Ancient Art to High-Tech Industry. In Metal
forming, 36, 2002, No. 9, pp. 30 – 34.
[4] Šugár, P., Šugárová, J. Analýza silového pôsobenia tlačného nástroja pri operácii ohýbania
materiálu za rotácie. In ITC 2007. Zlín : UTB Zlín, 2007. s. 123-127.
[5] Šugárová, J. Technologická dedičnosť materiálu tenkostenných rotačných súčiastok. In
Trendy lesníckej, drevárskej a environmentálnej techniky a jej aplikácii vo výrobnom
procese. Zvolen : TU Zvolen, 2001. s. 101-106.
[6] Šugárová, J., Šugár, P. Research study of strain distribution throughout the part after metal
spinning operations. In DAAAM 2002, Vienna : VUT Vienna, 2002. p. 545-546.
ACKNOWLEDGMENT
The results presented in the paper are based on investigation of research project “Expert
system for technological parameters optimization of metal spinning process“ – project No.
1/4097/07, funded by the Slovak Ministry of Education.
Praca wpłynęła do Redakcji 2.04.2008
Recenzent: dr hab. inż. Jan Materniak
ANALIZA DOKŁADNOŚCI KSZTAŁTU ELEMENTÓW
PRODUKOWANYCH PRZEZ WYOBLANIE
S t r e s z c z e n i e
Wyoblanie – drykowanie – jest starą metodą kształtowania materiału, wywodzącą się z metody kół garncarskich, znanej już w starożytnym Egipcie. W chwili obecnej jest to najnowsze, zaawansowane technicznie rozwiązanie (high-tech) oparte na technice komputerowej technologii
produkcji osiowosymetrycznych, wydrążonych (pustych w środku) elementów z cienkich blach
The shape accuracy analysis of machine parts produced by metal spinning
143
o określonych właściwościach warstw powierzchniowych. Jakość produkowanych elementów
zależy przede wszystkim od przyjętego procesu wyoblania.
W artykule zaprezentowano cząstkowe wyniki badań eksperymentalnych dotyczących analizy
dokładności kształtu elementów (próbek) produkowanych zgodnie z konwencjonalnym wyoblaniem metali z wielokrotnym przejściem narzędzia. Do celów badań eksperymentalnych stosowano
blachę o grubości 1 mm. Dokładność kształtowania była analizowana za pomocą trójwymiarowego optycznego systemu pomiarowego, pracującego na zasadzie triangulacji (każdemu zarejestrowanemu punktowi przyporządkowuje się z dużą dokładnością trójwymiarowe współrzędne,
a następnie tworzona jest sieć poligonowa powierzchni). W celu digitalizacji zastosowano trójwymiarowy mobilny system optyczny GOM ATOS I 350. Do wizualizacji odchyłek kształtowania
wykorzystano kolorowe pola.
Słowa kluczowe: wyoblanie, kształt, dokładność