According to the production process, diamond wire can be divided into electroplated diamond wire cutting and resin diamond wire. Diamond cutting wire is made by coating diamond on steel wire through a certain method. Through the diamond cutting machine, the diamond cutting wire can form a relative grinding movement with the object to achieve the purpose of cutting.
Diamond wire is made by consolidating high-hardness and high-wear-resistant diamond micropowder on the steel wire matrix by composite electroplating method to make a consolidated abrasive diamond saw wire. During the cutting process, 90% of the tensile strength comes from the steel wire, so the steel wire is crucial to the diamond wire.
During the free abrasive wire saw cutting process, the grinding liquid is sprayed directly onto the steel wire and silicon crystal by the nozzle, and the steel wire of the wire mesh drives the free abrasive to cut the silicon crystal. Unlike free abrasive, diamond wire differentially consolidates diamond to the steel wire, and the steel wire reciprocates to cut the silicon crystal. Traditional mortar uses the rapid movement of the steel wire to bring the abrasive liquid into the cut of the workpiece to produce a cutting action. During the cutting process, silicon carbide is washed away, and only continuous rolling grinding can be performed, which reduces cutting efficiency. The hardness of silicon carbide is 9.5 (Mohs), while the hardness of diamond is 10 (Mohs). The wire speed of diamond wire cutting is basically 15m/s, and the normal cutting mortar wire speed is basically 9-11.5m/s. If diamond wire is to make another breakthrough, it should be harder, with better self-sharpening (polycrystalline diamond), more stable consolidation method, and faster wire speed.
Diamond cutting wire has three major advantages over traditional processes:
1) Diamond wire cutting has less leakage, long life, fast cutting speed, high cutting efficiency, and improved production capacity;
2) Controlled quality, low single-wafer cost, the damage layer caused by diamond wire cutting is smaller than that of mortar wire cutting, which is conducive to cutting thinner silicon wafers;
3) Environmental protection, diamond wire uses water-based grinding fluid (mainly water), which is conducive to improving the working environment and simplifying post-processing procedures such as cleaning.
