Page 13 - Fall 2024 EDM Today

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Rsm infl uences, among other
factors, the extraction force
from the mold: the bigger, the
smaller the friction. This means,
for some applications, longer
lifetime of the mold, less
maintenance, and less deforma-
tion of sensitive plastic parts.
(See Fig. 6)
Fig. 6: Rsm
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Rsm also impacts the hydro-
phobic properties of a surface,
meaning its ability to repel water.
By adjusting the pulses of the
EDM generator, it is possible to
alter the Rsm while maintaining
the same Ra. (See Fig. 7)

Now, our one dimensional ruler
could be expanded and look as
shown in Fig. 8.
Fig. 7: Friction coeffi cient and hydrophobic angle vs Rsm
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EDM Today Magazine We just mentioned an important aspect of EDM: it has the capability, together
with other technologies like laser, to generate functional surfaces. Surface
structuring fi nds diverse applications, such as surface preparation for aero-
space industry bonding, creating light trapping with deep black surfaces, or
facilitating osseointegration in medical implant procedures. Innovative appli-
cations are superhydrophobic surfaces, used in various applications, including
self-cleaning materials, anti-icing coatings, and water-resistant textiles. (Lotus
leaf pattern or alike.) To characterize such a surface, a 3D standard is needed,
since functional surfaces are a mix of nano-, micro- and mini geometries.

this process, scanning surfaces to fi nd matches. EDM Today Magazine
EDM Today Magazine HOW TO MEASURE A 3D SURFACE EDM Today Magazine

3D surface metrology, as defi ned by the ISO 25178 standard, employs an optical
non-contact method. The surface data is categorized into primary, texture, and
Fig 8: A two dimensional ruler
waviness parameters.
Returning to the initial concept that measuring is
comparing, a future approach to surface characterization
could involve optical comparison with a large database of
surfaces. Artifi cial intelligence could play a crucial role in

A research project by the University of Applied Sciences
of Southern Switzerland has already demonstrated
This approach allows for verifi cation of the fi nal EDM Today Magazine
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promising results in this area. [1]
A camera was installed on a die sinking machine
(see Fig. 9) to capture images of numerous eroded
surfaces. These surfaces were measured, and their
roughness values were recorded in a database, forming
the training set. Utilizing artifi cial intelligence, the system
could identify any eroded surface by simply taking a
picture, and looking up in the database until it found a
match, eliminating the need for a measuring instrument.
workpiece (b), and integrated GUI (c)
roughness against the desired specifi cations, and if Fig 9: EDM die sinking machine with imaging sensor (a),
discrepancies are found, corrections can be made
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without unclamping the workpiece.

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EDM Today, Fall 2024 Issue