**4. Wear mechanism formed in the process of cutting with diamond frame saw**

Generally rock cutting mechanism is explained by the formation of indentation with plastic deformation and breaking mechanism of rock. When cutting depth of diamond is deep enough to produce visible cracks on a rock, breakages occur and chips are formed as a result of this. As can be seen schematically in Figure 12, there is a plastic deformation under the channel that is produced by the tangential movement of abrasive grain along the surface and there are two main crack systems named radial and lateral that are produced from this zone. Radial cracks are formed with wedge wear type when high normal force is used and when this force is removed, these cracks can continue to spread because of permanent tensile stress at the edge of crack. Lateral cracks start to be formed when he force is removed and can continue to spread with the effect of permanent tension (Konstanty, 2002).

**Figure 12.** Schematic view of plastic deformation zone formed during cutting (Konstanty, 2002)

In the cutting process with diamond segmented blades are moved with reciprocating motion at a sinusoidal speed that is about 2 m/s. Konstanty (2002) made some researches on the cutting mechanism with diamond blade saw and defined the cutting zone during this cutting. Schematic view of cutting zone determined by Konstanty (2002) is shown in figure 13. Here, in order to make the definition, it is accepted that diamond grains in diamond zones are placed with the same protrusion height and cutting zone is the same all along the segment. But diamond grains on diamond segments have different protrusion heights**.** This complicates the process of defining cutting process. As can be seen in the cutting zone in figure 3.20, a pressure is produced on matrix as rock fragments accumulated in the front and behind the diamond grains can not be removed. Magnitude of pressure resulting from the wedging of rock fragments cause wear in the contact zone that is the weakest point between diamond and matrix.

Theories on Rock Cutting, Grinding and Polishing Mechanisms 199

As can be seen in Figure 14, the main deformation of natural stone in low cutting depth is explained as plastic deformation. In parallel with the increase in cutting depth, while lateral cracks increase, plastic deformation of natural stone decreases and as a result, chip is formed. Some small lateral cracks on the surface can have a flaky structure on the base of cutting channel like a shell. Lateral cracks on different directions leave the semicircular channel behind the diamond the cuts on the surface. Plastic deformation zone stays on the base of cutting channel. Divergence on the cutting zone resulting from the increase of shearing cracks on the surface along the breaking zone seems like a continuous chip

Cutting with diamond blade saw is the continuous cutting movement of many segments on the surface of rock. Cutting with diamond segment can be defined as the cutting of a diamond cutter that cuts from many points in different cutting depths. As diamonds make chips and cuts, cracks are formed and they join and as a result of this, natural stone is

broken. This situation is given in Figure 15 as stated by Wang and Clausen (2002).

**Figure 15.** Cutting process of marble with diamond segments (Wang and Clausen, 2002)

shape of cutter and aspects of rock (Konstanty, 2002; Wang and Clausen, 2002).

**5. Wear mechanism formed during cutting with diamond wire system** 

The principle behind diamond wire cutting involves pulling a spinning, continuous loop of wire mounted with diamond bonded steel beads through the stone to provide the cutting

Natural stone cutting mechanism with diamond blade saw system is explained as plastic deformation (breaking zone) and brittle breaking of rock. Formation of chip can be used in the explanation of cutting with frame saw system as s baseline. Plastic deformation and breaking of rock is affected from cutting conditions such as cutting depth, cooling operation,

formation (Wang and Clausen, 2002).

**Figure 13.** Schematic demonstration of cutting zone in the frame sawing system (Konstanty, 2002)

In the process of cutting with diamond blade saw, cutting of diamond segments is similar with cutting of many diamond grains. Cutting principal of diamond grain in segments are shown in Figure 14.

**Figure 14.** Cutting mechanism of marble with diamond grain (Wang and Clausen, 2002)

As can be seen in Figure 14, the main deformation of natural stone in low cutting depth is explained as plastic deformation. In parallel with the increase in cutting depth, while lateral cracks increase, plastic deformation of natural stone decreases and as a result, chip is formed. Some small lateral cracks on the surface can have a flaky structure on the base of cutting channel like a shell. Lateral cracks on different directions leave the semicircular channel behind the diamond the cuts on the surface. Plastic deformation zone stays on the base of cutting channel. Divergence on the cutting zone resulting from the increase of shearing cracks on the surface along the breaking zone seems like a continuous chip formation (Wang and Clausen, 2002).

198 Tribology in Engineering

diamond and matrix.

shown in Figure 14.

In the cutting process with diamond segmented blades are moved with reciprocating motion at a sinusoidal speed that is about 2 m/s. Konstanty (2002) made some researches on the cutting mechanism with diamond blade saw and defined the cutting zone during this cutting. Schematic view of cutting zone determined by Konstanty (2002) is shown in figure 13. Here, in order to make the definition, it is accepted that diamond grains in diamond zones are placed with the same protrusion height and cutting zone is the same all along the segment. But diamond grains on diamond segments have different protrusion heights**.** This complicates the process of defining cutting process. As can be seen in the cutting zone in figure 3.20, a pressure is produced on matrix as rock fragments accumulated in the front and behind the diamond grains can not be removed. Magnitude of pressure resulting from the wedging of rock fragments cause wear in the contact zone that is the weakest point between

**Figure 13.** Schematic demonstration of cutting zone in the frame sawing system (Konstanty, 2002)

**Figure 14.** Cutting mechanism of marble with diamond grain (Wang and Clausen, 2002)

In the process of cutting with diamond blade saw, cutting of diamond segments is similar with cutting of many diamond grains. Cutting principal of diamond grain in segments are Cutting with diamond blade saw is the continuous cutting movement of many segments on the surface of rock. Cutting with diamond segment can be defined as the cutting of a diamond cutter that cuts from many points in different cutting depths. As diamonds make chips and cuts, cracks are formed and they join and as a result of this, natural stone is broken. This situation is given in Figure 15 as stated by Wang and Clausen (2002).

**Figure 15.** Cutting process of marble with diamond segments (Wang and Clausen, 2002)

Natural stone cutting mechanism with diamond blade saw system is explained as plastic deformation (breaking zone) and brittle breaking of rock. Formation of chip can be used in the explanation of cutting with frame saw system as s baseline. Plastic deformation and breaking of rock is affected from cutting conditions such as cutting depth, cooling operation, shape of cutter and aspects of rock (Konstanty, 2002; Wang and Clausen, 2002).
