Production Technique for Diamond Segments
Diamond segment is the working part of a diamond saw blade. Segment is made of diamond powder and metal bond, diamond as a superhard material, serving as cutting and grinding, and metal bond is a bonding agent to hold diamond, a metal bond could be an elemental powder or a metal alloy powder, diamond ratio and metal bond in different combination is named formula. As per different application, formula and diamond powder will be different accordingly.
Choice of Diamond Segment production technique
1.Diamond Grit Size
If diamond power in single grit size and in coarse grit, its segment is supposed to be with high sharpness and good cutting efficiency, at the same time, bending strength of diamond segment is be lower; if diamond grit is fine grit or mixed fine and coarse grits, segment will be more wear resistance but cutting efficiency will be lower. Overall, 50/60# diamond grit is a maximum choice in diamond segment production.
With diamond density increases, diamond segment sharpness and cutting efficiency will decrease to some extent, segment lifespan will increase thereby, however, if too high density, segment will go dull and not able to cut. And if using lower diamond density and coarse grit diamond, cutting efficiency will be increased. It will be a smart choice to use different density on different parts or layers of diamond segment (usually in a 3 or more multi layer segments, a lower density diamond layer will be used on the middle layer or layers), it helps create a groove in the middle when segment is working and to avoid saw blade vibration or slide cut, and therefore increase stone cutting precision;
Diamond strength is an important index for segment cutting performance. If diamond with too much strength, diamond crystal is not easy to break, and resulted in grounded or polished diamond and therefore cutting sharpness decrease and lower cutting efficiency; however, if diamond strength too low, it will be easy to break after impact, and so it can not serve its cutting mission. As per experiences, it is suggested 130N to 140N diamond strength for diamond segments.
Performance of a cutting segment is not only decided by diamond powder but also greatly depends on diamond and metal bond or matrix. For marble and other soft stones, cooper based (Cu+) metal bond is more in use since soft stone cutting segments require less on segment mechanical properties, however, Cu+ metal bond is with lower sintering temperature, and less strength and hardness but higher elasticity, bonding strength with diamond is somehow lower. An introduction of tungsten carbide (WC) and Cobalt power, together with Cu, Sn, Zn and other lower melting point and softer metal materials into metal bond, this helps a lot to increase bonding strength, hardness and bonding quality.
5. Sintering Technique
With sintering temperature increased, metal bond compact degree will increase and so bending strength as well. And with the thermal insulation time extends, bending strength of empty matrix and diamond blocking will first increase and then decrease, therefore a sintering temperature of 800 ℃ and with a thermal insulation time at 120 seconds will help make better segment.