Manufacturing and
Materials Processing
Journal of
Article
Influence of Process Parameters and Initial Surface on Magnetic
Abrasive Finishing of Flat Surfaces on CNC Machine Tools
Andrii Zelinko
1,
*, Florian Welzel
1
, Dirk Biermann
2
and Viktor Maiboroda
3
Citation: Zelinko, A.; Welzel, F.;
Biermann, D.; Maiboroda, V.
Influence of Process Parameters and
Initial Surface on Magnetic Abrasive
Finishing of Flat Surfaces on CNC
Machine Tools. J. Manuf. Mater.
Process. 2021, 5, 108. https://doi.org/
10.3390/jmmp5040108
Academic Editors: Arkadiusz Gola,
Izabela Nielsen and Patrik Grznár
Received: 14 September 2021
Accepted: 11 October 2021
Published: 14 October 2021
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4.0/).
1
GFE—Gesellschaft für Fertigungstechnik und Entwicklung Schmalkalden e.V., Näherstiller Str. 10,
98574 Schmalkalden, Germany; f.welzel@gfe-net.de
2
Institute of Machining Technology, TU Dortmund University, Baroper Strasse 303,
44227 Dortmund, Germany; dirk.biermann@tu-dortmund.de
3
Institute of Mechanical Engineering, National Technical University of Ukraine “KPI”, Peremohy Ave. 37,
03056 Kyiv, Ukraine; maiborodavs@mail.ru
* Correspondence: a.zelinko@gfe-net.de; Tel.: +49-3683-6900-18
Abstract:
Magnetic abrasive finishing (MAF) shows a high potential for use on computerized
numerical control (CNC) machine tools as a standard tool to polish workpieces directly after the
milling process. This paper presents a new MAF tool with a single, large permanent magnet
and a novel top cover structure for finishing the plain ferromagnetic workpieces. The top cover
structure of the MAF tool, combined with an optimized working gap, ensures the effect of mechanical
powder compaction, which leads to a significant increase in process capability and surface roughness
reduction. The influence of the process parameters such as feed rate, equivalent cutting speed,
working gap (including for three grain sizes) and the gap to the magnet was investigated. In addition,
the influence of the initial surface after face milling, end milling, ball end milling and grinding on the
surface quality after MAF was investigated. Furthermore, three typical surfaces after milling and
MAF were analyzed. By magnetic abrasive finishing, a significant surface quality improvement of
the initial milled surfaces to roughness values up to Ra = 0.02
µ
m and Rz = 0.12
µ
m in one processing
step could be achieved.
Keywords:
magnetic abrasive finishing; surface finishing; CNC machine tools; ferromagnetic work-
piece
1. Introduction
Magnetic abrasive finishing (MAF) is characterized by a high complexity of the process,
powder motion kinematic, mechanical and magnetic interaction of forces and numerous
influencing factors. To these factors belong process kinematics (finishing of flat or freeform
surface, wave or tube, etc.), process parameters (cutting speed, feed rate, working gap and
magnetic flux density), workpiece properties (mechanical and magnetic properties, initial
surface), MAF tool (quantity, dimension, arrangement of permanent- or electromagnets),
magnetic abrasive powder (type, manufacturing method, grain size, ferromagnetic and
abrasive percentage) and cooling lubricant (type, chemical reactions).
Various studies investigate the process parameters [
1
–
7
] and describe for example the
influence of the working gap, the abrasive weight percentage and rotational speed on the
normal finishing force and torque, while MAF of the paramagnetic disk workpiece that
was clamped between two MAF tools [
1
]. Further work describes the influence of abrasive
grain size as well as feed rate in addition to abovementioned process parameters on the
percentage change in surface roughness Ra, during the equal MAF process of paramagnetic
stainless steel and copper alloy [
2
]. The working gap has the highest influence on the
surface roughness improvement and normal finishing force by MAF [
1
,
2
]. The voltage
supplied to the electromagnet also has a significant impact on the surface roughness
improvement as well as on the normal and tangential cutting force, while MAF of SS316L
J. Manuf. Mater. Process. 2021, 5, 108. https://doi.org/10.3390/jmmp5040108 https://www.mdpi.com/journal/jmmp
