**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 action (Figure 16). Through the combination of the spinning wire and the constant pulling force on the wire, a path is cut through the stone. In marble quarrying through diamond wire cutting, the initial step for making a vertical cut is to drill two holes, one vertical and one horizontal, which intersect at a 90° angle. The diamond wire is then threaded through these holes, mounted around the drive wheel, and the two ends are clamped together to form a continuous loop. The drive wheel may be set at any angle, from vertical to horizontal, required to facilitate cutting.

Theories on Rock Cutting, Grinding and Polishing Mechanisms 201

**Figure 17.** Schematic presentation of cutting the natural stone with diamond bead (Bortolussi et al.,

This mechanism includes abrading and polishing mechanisms on grinding heads that are

Although some of grinding mills are used in the literature, there are some significant differences between the grinding mechanisms of grinding mills. Abrading that is made with the help of abrasive grains on the surface of grinding heads is in fact quite similar with the abrading on sandpaper. Abrasive grains on the abrading product makes cutting, rubbing or ploughing as of their position. According to the application of abrading operation, complication of the mechanism is somewhere in between the mechanisms that are produced

If grinding heads is turning around vertical axis on material surface, grains on it will make cutting, breaking through or friction during abrading. If there is the linear movement besides turning, the situation will be more complicated. Abrasive grain will be able to make

In figure 18, the model that is developed by Lawn and Swain (1975) about crack movement on material surface and material removal. At the first contact point between grinding and surface, because of the applied loads high stress occurs. If the tip of the abrasive grain is perfectly sharp (namely, if radius of curvature is 0) stresses at this point will be infinite. These dense stresses relax with permanent changes in the shape and changes in density.

When applied loads reach a critical value, the middle crack shown with M start to increase because of tensile stress occur on vertical plane. In parallel with the decrease of load, middle fracture filling and when it reduced more, lateral cracks shown with L occur. These cracks are formed as there are residue elastic stresses after relaxation in contact points. Crack reaches surface with the removal of complete load and it cause wear with the breaking of

According to Chandrasekar and Farris (1997), a few mechanisms are dominant in removing material from brittle surfaces. These are brittle break that is formed according to crack

**6. Wear mechanism formed during surface polishing applications** 

used for leveling and polishing of surfaces of different materials.

in sandpaper and grinding mill applications.

material from surface.

these three moves during operation in different times.

1994)

The diamond wire is comprised of a steel cable on which small beads bonded with diamond abrasive are mounted at regular intervals with spacing material placed between the beads. The beads provide the actual cutting action in this operation. They are bonded with diamond by one of the two methods: electroplating or impregnated metal powder bonding.

**Figure 16.** Situation of the diamond wire during the cutting operation (Ozcelik et al., 2002)

In the process of cutting with diamond wire system (Figure 17), diamond grains, sintered with metal powder as bead form, contact material surface similar with the circular saw and make grinding, cutting or abrading processes according to contact angle.

During cutting natural stone with diamond wire, contact angle between diamond grains and rock surface vary according to the path of steel rope (on which diamond beads are lined) in the rock rather than the diamond grains on bead.

horizontal, required to facilitate cutting.

action (Figure 16). Through the combination of the spinning wire and the constant pulling force on the wire, a path is cut through the stone. In marble quarrying through diamond wire cutting, the initial step for making a vertical cut is to drill two holes, one vertical and one horizontal, which intersect at a 90° angle. The diamond wire is then threaded through these holes, mounted around the drive wheel, and the two ends are clamped together to form a continuous loop. The drive wheel may be set at any angle, from vertical to

The diamond wire is comprised of a steel cable on which small beads bonded with diamond abrasive are mounted at regular intervals with spacing material placed between the beads. The beads provide the actual cutting action in this operation. They are bonded with diamond by one of the two methods: electroplating or impregnated metal powder bonding.

**Figure 16.** Situation of the diamond wire during the cutting operation (Ozcelik et al., 2002)

make grinding, cutting or abrading processes according to contact angle.

lined) in the rock rather than the diamond grains on bead.

In the process of cutting with diamond wire system (Figure 17), diamond grains, sintered with metal powder as bead form, contact material surface similar with the circular saw and

During cutting natural stone with diamond wire, contact angle between diamond grains and rock surface vary according to the path of steel rope (on which diamond beads are

**Figure 17.** Schematic presentation of cutting the natural stone with diamond bead (Bortolussi et al., 1994)
