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68 UEC Int’l Mini-Conference No.54

Effect of tube dimension and material
on formability in eccentric tube

processing by expansion drawing

Phone Myint Aung, Shohei Kajikawa
Department of Mechanical Engineering and Intelligence Systems
University of Electro-Communications Tokyo, Japan

1.Introduction 4.Results

Tube drawing is widely used in manufacturing high-precision
tubular products for industries such as automotive, aerospace,
and energy.
Traditional tube drawing produces uniform tubes, but certain
applications require intentional dimensional asymmetry or
eccentricity.
Eccentric tube expansion drawing uses an eccentric plug to
deliberately shift material distribution, producing tubes with
variable wall thickness or inner contours.
Understanding how tube dimensions and material properties Fig.1 Thickness variation of a tube cross section
affect formability is crucial for optimizing process parameters and
ensuring product quality.
2.Objective

To investigate how different tube dimensions (diameter, wall
thickness) and materials influence:
Drawing forces
Wall thickness distribution
Dimensional precision
Occurrence of defects during eccentric tube expansion drawing

3.Methodology Fig.2 Thickness of a tube across the length ( 0 to 120mm)
Experimental Design
Tested tubes of various metals (e.g., carbon steel, aluminium alloy,
copper alloys).
Varied initial diameters, wall thicknesses, material, and plug
eccentricity.
Process Execution
Tubes drawn through eccentric plugs under controlled speed and
lubrication.
Forces and stroke measured in real-time.
Analysis
Measured tube dimensions post-drawing.
Fig.3 Thickness deviation ratio vs eccentricity
Evaluated wall thickness variation and eccentricity.
Performed FEM analysis using Elfen software. 5. Conclusion and future plan
So far, this research has illustrated the tube drawing process and
how the thickness of a tube varies based on the eccentricity of
the tube as shown in fig.2
This research has also demonstrated how the eccentricity affects
on the tubes with different thickness.
In the future work, different materials and different finite element
analysis methods will be used to better understand the
characteristics of tube formation.
[1] Zhang, S., Kawaguchi, H., Kuboki, T., Akasaka, I.,Terashita, Y ., Akiyama, M. and Kajikawa, S., 2022, Effect of Plug Angle on Formability in Tube Drawing
Refrences with Diameter Expansion, Journal of Japan Society for Technology of Plasticity Vol 68, No.748 (2022), pp. 174-179.
[2] Zhang, S., Kuboki, T., Akiyama, M., Kajikawa, S, Influence of mechanical properties of tube on forming limits and deformation characteristics in an
expansion drawing process, Journal of Manufacturing Science and Engineering 146 (7), 071005