CUTTING OF BAKOR BY A SEGMENTED TOOL
WITH CLUSTERED DIAMONDS
A. V. Belyakov
and S. I. Tserman
Translated from Novye Ogneupory, No. 5, pp. 34 – 37, May, 2011.
Original article submitted March 29, 2011.
This article examines the processes that take place during the cutting of Bakor with a diamond tool in which
the diamond-bearing layer has a clustered structure. Such a structure ensures more uniform loading of the cut-
ting granules, which improves the cutting ability of the segments and increases the service life of the tool.
Keywords: refractories; Bakor; cutting; diamond tool; diamond cluster.
In ceramics production, machining with a diamond tool
is often done to obtain products with highly accurate dimen-
sions. Such machining is used in particular to impart very ac-
curate dimensions to fused refractories made of Bakor (the
with impurities), which are employed in
glassmaking furnaces. To perform this operation, it is neces-
sary to have an efficient diamond cutting tool and efficient
cutting regimes. The goal of the research described in this ar-
ticle was to improve the structure of the diamond-bearing
layer of a cutting tool for its use in cutting Bakor.
In regard to machining, ceramic materials can be divided
into two main groups: easy-to-machine ceramics, typical rep-
resentatives of which include various classes of fireclays;
hard-to-machine ceramics, which are hard, dense, strong ma-
terials. Fused Bakor is particularly representative of this
group. The specific features of the machining of brittle non-
metallic materials determine their set of physico-mechanical
properties, specifically: strength and microhardness, as well
as structure and texture.
The current thinking with respect to the cutting of ceram-
ics by diamond tools is that this operation is accompanied by
comminution of the tool and the formation of an abrasive
suspension in the liquid lubricant-coolant. The most efficient
cutting regime is the self-sharpening regime, in which abra-
sive particles in the slurry that is formed remove binder from
the spaces between the diamond granules and expose new
granules in the process. The diamonds retain their cutting
properties as this takes place. If the methodology used to
evaluate the machineability of natural materials [1, 2] is ap
plied to refractories made of Bakor — a material that is ex-
tremely difficult to machine - then it becomes possible to
construct a general formulation for the main requirements in
the design of the diamond-bearing layer of the tool and the
cutting operation itself:
– the diamond granules must be of high strength and be
present in a high concentration, which are the reasons for the
high hardness and mechanical strength of Bakor;
– cutting depth is increased to compensate for the lower
productivity and slower tool feed (cm
/min) caused by the
high hardness and mechanical strength of Bakor ;
– compositions with a low resistance to hydraulic abra-
sion by the slurry must be used as the metallic matrix for the
diamonds in the segments, this being necessary due to the
relatively low abrasiveness of the cutting products; the cut-
ting products should remove the matrix at a sufficiently high
rate in order to expose new diamond granules.
In keeping with these requirements, the cutting layer was
designed using high-strength grade-AS300 diamonds in ac-
cordance with GOST 9206 and GOST R 52370. The dia-
monds have a granularity of 400/315 and were used in a con-
centration equal to 42.5 . The metallic binder employed
for the diamonds was a very “soft” (easily worn) powder
composition based on tin bronze.
The segments were made on equipment produced by the
German company “Dr. Fritsch.” The segments were fabri-
cated by hot pressing of a diamond-bearing charge obtained
by granulation of the powdery diamond-metal mixture with
the use of a polymer binder. The hot-pressing operation was
carried out at 850°C with at a pressure of 25 MPa applied for
3 min. The mixing technology that was used resulted in a
random distribution of diamond granules in the matrix. The
Refractories and Industrial Ceramics Vol. 52, No. 3, September, 2011
1083-4877/11/05203-0195 © 2011 Springer Science+Business Media, Inc.
Russian University of Chemical Engineering, Moscow, Russia.
”Adel” Company Group, Zelenograd, Russia.