Аннотация:
Cutting of solid construction materials during repair and restoration
work is carried out with diamond discs and CBN discs on a metal bond with
speeds up to 80 m/s. The cutting process is accompanied by significant heat
generation, as a result of which the cutting disc heats up intensively. When heated
to a temperature of 500–600 °C, the strength characteristics of the disk are
halved, which can lead to rupture and seizure of the disk and loss of the diamond
layer. Disk heating temperature should not exceed 600 °C. The operating time of
the diamond cutting disc is the time during which it is heated during continuous
operation to a temperature of 600 °C. The cooling media used in cutting are
intensively discarded by the air flows of the boundary layer of air that circulate
near the rotating circle. Knowing the speed and dimensional characteristics of
these flows, we can develop a rational cooling system. The purpose of the study is
to determine the conditions of transportation of cooling media, ensuring their
guaranteed entry into the cutting zone to create the maximum cooling effect. This
work defines the speeds of flowing air in the near-wall area and in the area
tangential to the disk with the help of mathematical modeling. The thickness of
the air layer, which rotates at a speed of up to 0.5 circle speed was determined,
taking this value as the “boundary layer thickness”. The change in air pressure in
the cutting zone between the cutting grains was determined, too. It is established
that air pressure can vary from 0.5–1.7 MPa. In this regard, the cooling medium
supplied under the circle, inevitably displaced from the cutting zone. In order for
the cooling medium to penetrate into the cutting zone, it must be fed under a
pressure that exceeds the air pressure in the cutting zone.
