Papers by Keyword: Diamond Segment

Abstract: An attempt was taken to simulate the bending strength of diamond impregnated segments in three point bending tests by using a discrete element method (DEM). The influences of main bond matrix components (Fe and Cu), the porosity in the matrix, the coefficient of friction among the matrix particles, and the connection strength between abrasive particles and matrix particles on the bending strength were investigated through simulation. It is found that the bending strength increases with the proportion of Fe but decreases with the increase of porosity. An increase in both the friction coefficient of the matrix particles and the bonding strength between the diamond grains and metal matrix particles can also lead to the increase of bending strength.

Abstract: An experimental study was undertaken to compare the mechanisms of two different processes to dress metal-bonded diamond segments. In one case, a piece of vitrified SiC wheel was used as workpiece and sawn by diamond segments attached to a sawblade. In another process, a diamond segment was used as workpiece and ground by an Al2O3 wheel. Spindle power was measured in sawing and horizontal force was monitored in grinding, in which case the latter was then used to get the consumed power in grinding. Specific energies were then calculated from the measured or converted power. For sawing of SiC wheel with the diamond sawblade, the maximum specific energy was found to be only 0.5 J/mm3, whereas the specific energy was up to 25 J/mm3 in the grinding of the diamond segment.

Abstract: The performances of metal-bond of diamond cutting tools were investigated by changing the cobalt and bronze ratio conversely as the matrix material. Diamond tools were fabricated by cold pressing and sintering under pressure at the temperature up to 750 °C. Investigation of the microhardness behavior of the segments was showed that increasing the cobalt ratio causes the increase of the hardness of the matrix material. This caused to decrease of the wear rate of the matrix. Because the matrix wears more slowly than the diamonds, the space between the cutting edges and the matrix is constantly reduced. The swarf cannot be carried away properly, and the segment will continuously lose its ability to cut with higher cobalt contents.

Abstract: Diamond segments were fabricated by cold pressing and sintering under pressure at the temperature up to 750 °C. It was obtained from this study that if we increase the cobalt ratio, the hardness of the matrix increases and the wear rate of the segments decreases. But the optimum matrix composition with less wear rate must ensures that the acceptable matrix toughness. Because the harder matrix wears more slowly than the diamonds, the space between the cutting edges and the matrix is constantly reduced. Because the swarf cannot be carried away properly, and the segment will continuously lose its ability to cut. From this point of view, the cobalt ratio in matrix composition for this formulation should not be higher than the 60 wt.% in order to have a good cutting ability.