World Grain - November 2018 - 96

TECHNICAL PROFILE

TITANIUM-COATED

ROLLS

Longer life, less maintenance among the advantages for flour millers
by Daniele Rossini, Eloisa Martino and Marco Galli

T

he correct operation of an entire milling plant is
determined by many factors, including some related to the design, the performance of all the machines, as well as correct and timely maintenance. One
of those factors is the grinding rolls, which are used to
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Cremona, Italy-based Ocrim S.p.A. has studied and
designed the way to optimize and enhance the mill's
operation, linked to the performance of the roller mills,
to optimize both time and maintenance costs. This led
the company to focus on the grinding rolls, designing
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possible for the end user. For this market request, the
solution presented involved including titanium-coated
UROOVIRUWKHÀXWHGSDVVDJHVLQWKHJULQGLQJSURFHVVHQsuring a much longer life of the rolls currently used by
the milling industry.
Ocrim's Research and Development department, following this new engineering strategy, carefully studied
the results related to the titanium coating of the rolls in
order to share with its customers the important opportunities that this product can offer.

cutting and its compression. The diagrammatic study to
obtain the best possible yield from the plant is strongly
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the plant because it is in the best conditions to achieve
what is envisaged by the diagram, therefore it is crucial
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long as possible
The grinding rolls are all made of chilled-iron cast
alloy with different hardness, according to the requirements or the technological diagram. The duration of
the rolls is thus directly dependent on its hardness. The
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maintains its characteristics for longer when the roll
has high hardness values (e.g. 530 HB).
In this regard, Ocrim's Research and Development
department has conducted several research studies and
trials, achieving tangible results through the application of a special titanium coating for the corrugated
rolls. This coating causes a considerable increase in the
surface hardness values and consequently increases the
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RESEARCH TRIALS
The titanium coating of the rolls is carried out using cut,QÀRXUPLOOLQJZKHDWJUDLQVDUHFUXVKHGWRREWDLQÀRXU ting-edge technology, called Plasma Assisted Chemical
and semolina due to a combined action involving grain Vapor Deposition (PACVD), which ensures the best possible results. This sophisticated operation consists in creating a multilayer coating, for a total thickness of about
3 microns of titanium nitride (TiN) and titanium boride
(TiB). This ensures the combination of the best characteristics of the two materials: the high hardness of the TiB
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Given the low thickness of the coating, one cannot
talk about the hardness of the roll, but of the surface
hardness of the roll (microhardness), which reaches the
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hardness of the commonly used traditional rolls, which
can reach up to 560 HV (in the best cases).
Rolls with titanium coating. Images courtesy of Ocrim.

96

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