special - Alu-web.de

SPECIAL
number of usable threads resulting
in lower transferable forces. When
using a circular milling process for
the production of holes, the displacement
of the wire is negligible due to
low process-related feed forces, even
if the wire is located in the middle of
the hole. Therefore, the tensile force
is increased by the reinforcement in
every case where circular milling is
used as a process for hole making.
When flow-drilling is used before
threading, integrating two reinforcing
elements into the lateral area of
the hole leads to an increase of the
transferable tensile force. In this case,
the maximum tensile force measured
considerably exceeds the test load of
F z = 17980 N given in the standards
for nuts made of the comparable alloy
AlMgSi1 [10].
Conclusions and outlook
Composite extrusion offers great opportunities
for lightweight applications.
In experimental investigations,
it was shown that it is possible to
achieve a higher volume of reinforcement
through the reduction of the
profile thickness and the embedding
of further reinforcing elements, but
the influence of the reinforcement on
the material flow increases with the
number of wires and the necessarily
more complex die design. In another
experiment, metallic flat tapes were
already embedded successfully into
aluminium profiles to improve the
mechanical properties. Other experimental
trials concentrate on embedding
ceramic elements with a higher
specific stiffness.
Flow-drilling and threading op-
ALUMINIUM · 4/2010
ALUMINIUM EXTRUSION INDUSTRY
erations are viable for the innovative
steel-wire reinforced aluminium profiles.
The influence of the process parameters
on the quality of the formed
collar is shown for the feed but has
to be further analysed. The position
of the hole relative to the reinforcing
element is a major influencing factor.
Threads can be manufactured in any
position by diverse threading operations
but the maximum transferable
forces determined by tensile tests differ
because of an unequal number of
usable threads. The combination of
flow-drilling and thread forming results
in the highest transferable tensile
forces due to the advantageous
grain flow within the workpiece and
the highest number of usable threads.
Threading of steel tape reinforced
profiles is to be further investigated.
Acknowledgement
This paper is based on investigations
of the Transregional Collaborative
Research Centre SFB/TR10, which is
kindly supported by the German Research
Foundation (DFG).
References
[1] Ames, R.; Theler, J.-J.: Verfahren und
Vorrichtung zum Herstellen von Verbundprofilen
beispielsweise Stromschienen.
Patent DE 2432541 C2, Aluminiumwalzwerke
Singen, Date of filing 4.7.1974
[2] Müller, K.: Strangpressen von Halbzeugen
aus metallischen Verbundwerkstoffen.
In: Strangpressen / Bauser, M.; Sauer, G.;
Siegert, K., 2. Edition, Aluminium Verlag,
Düsseldorf, 2001, pp. 464-483
[3] Schikorra, M.; Tekkaya, A. E.; Kleiner,
M.: Experimental investigation of embedding
high strength reinforcements in
extrusion profiles. Annals of the CIRP
Fig. 8: Maximum tensile forces transferred by threads produced via thread forming, tapping and thread milling
– Manufacturing Technology, Volume 57,
Issue 1, 2008, pp. 313-316
[4] Nakamura, T., Tanaka, S., Hiraiwa, M.,
Imaizumi, H., Tomizawa, Y., Osakada, K:
Friction-assisted extrusion of thin strips of
aluminium composite material from powder
metals. Annals of the CIRP, Volume 41,
Issue 1, pp. 281-284
[5] Klaus, A.; Schomäcker, M.; Kleiner, M.:
First Klaus, A.; Schomäcker, M.; Kleiner,
M.: First Advances in the Manufacture
of Composite Extrusions for Lightweight
Constructions. In: Light Metal Age Vol. 62
(2004), No. 8, pp. 12-21
[6] Tikal, F.; Holsten, S.; Schäfer, M.: Effiziente
Herstellung von Innengewinden
durch Kaltumformen – Werkstofffluss
beim Gewindefurchen, VDI-Z Integrierte
Produktion, 2006, Vol. 2, pp. 45-48
[7] N. N.: VDI 3334 Machining of internal
threads – General information, basic principles,
techniques, Beuth-Verlag Berlin
(Germany), 2009
[8] Heiler, R.: Fließlochformen und Gewindefurchen
auf NC-gesteuerten Werkzeugmaschinen,
Dissertation, VDI-Verlag
Düsseldorf (Germany), 1999, ISBN 3-18-
352602-6
[9] Warrington, C.; Kapoor, S.; DeVor, R.:
Experimental investigation of thread formation
in form tapping, Journal of Manufacturing
Science and Engineering, 2005,
Vol. 127, pp. 829-836
[10] N. N.: DIN EN 28839 Mechanical
properties of fasteners – bolts, screws and
nuts made of non-ferrous metals, Beuth-
Verlag Berlin (Germany), 1991
Authors
1 Dipl.-Ing. Timo Engbert, Prof. Dr.-Ing.
Dirk Biermann, Dr.-Ing. Dipl.-Inform.
Andreas Zabel: Institute of Machining
Technology (ISF), Technische Universität
Dortmund
2 Dipl.-Wirt.-Ing. Daniel Pietzka, Prof. Dr.-
Ing. A. Erman Tekkaya, Dipl.-Ing. Nooman
Ben Khalifa: Institute of Forming Technology
(IUL) and Lightweight Construction,
Technische Universität Dortmund
41