Research On Resin Bonded Diamond Wire Saw

Resin bonded diamond wire saw is mainly used for cutting hard brittle materials. With a large demand for substrate of LED chip, sapphire is widely used in the substrate industry beca use of its excellent properties. With the rapid development of solar cells and integrated circuit s, the demands of silicon wafer are more and more, and the size and the requirement of surfac e quality the silicon wafers and sapphire are more strict. silicon wafer with bigger size and hig her the surface quality requirements has more stringent requirements of cutting tool. Diamond wire saw, as cutting tools of silicon wafers and sapphire, has a increasing market demand.Resin bond diamond wire saw is a line cutting tools which is obtained by using the resin bond diamond abrasive consolidated on a saw wire substrate, and then cured by heat or light.Nowadays, problems in the actual production are that there are no good performances of toughness and heat resistance of resin binding agent which was used to produce resin bond diamond wire saw.In this study, two kinds of modifiers, o-cresol and diethylene glycol, are selected to improve the toughness and heat resistance of phenolic resin. By measuring their properties,phenolic resin of best performances is identified. And the matrix of diamond wire saw was determined by comparing tensile propertie of two species saw wire substrate. The size of the abrasive diamond was depended on the diameter of saw wire substrate and the thickness of the combined layer.The researches of this project as follows:(1) The selection of the substrate of resin bonded diamond wire saw: the tensile tests of316 L stainless steel wire and piano wire was made, and the diameters of them are 0.12 mm,0.15 mm, respectively. Compared the tensile strength of them, and the 316 L stainless steel wire was selected with a tensile strength of 2800 MPa.(2) The selection of the abrasives of resin bonded diamond wire saw: as the abrasive of resin bonded diamond wire saw, the number of Grain Size of diamond is 400 mesh.,treatment of the surface of the substrate was carried on.(3) O-cresol modified phenol resin: o-cresol can improve significantly the heat resistance of the phenolic resin. Experiments show that when the content of cresol is 10%, it has best performance. At this time, the viscosity and solids content of o-cresol modified phenolic resin are 1296 m Pa·s and 76.2%, respectively. The bending strength is 40.24 MPa, and the impact strength is 2.7KJ / m2; Shore hardness is 85.4HD, and shear bond strength is 19.56MPa; and its Friction coefficient is 0.239. Its initial decomposition temperature is 314℃, and when theweight maintenance rate are 10% and 20%, corresponding to the temperature is 468℃and529℃, respectively. when the temperature is 600℃, the weight maintenance rate of phenolic resin is up to 50.27%.(4) O-cresol/diethylene glycol-modified phenolic resin: diethylene glycol can significantly improve the impact toughness of and the shear bond strength the phenolic resin.Experiments show that when the content of cresol is 10%, and diethylene glycol is 15%; it has the best performance and is suitable for the preparation of diamond wire saw. The viscosity and solids content are 10500mPa·s and 74.06%, respectively. The bending strength is50.91 Mpa and the impact strength is 6.3KJ / m2; Shore hardness is 80.2HD, and shear bond strength is 32.81MPa; and its Friction coefficient is 0.216. When the temperature is 600℃,the weight maintenance rate of phenolic resin is up to 39.8%.(5) By comparison three resins, pure phenolic resin, o-cresol modified phenolic resin and o-cresol /diethylene glycol modified phenolic resin: the heat resistance of O-cresol modified phenolic resin is best. And when the temperature is 600℃, the weight maintenance rate of phenolic resin is up to 50.27%. While its toughness and bond strength is so low that it does not apply to the preparation for diamond wire saws. Though the heat resistance of o-cresol/diethylene glycol-modified phenolic resin is lower than o-cresol modified phenolic resin, its Toughness and bond strength is best. Integrated various properties, it was obtained that when O-cresol content of 10wt%, and diethylene glycol is 15%; modified phenolic resin has the best performance and is suitable for the preparation of diamond wire saw.(6) The coating of resin bonded diamond wire saw: O-cresol/diethylene glycol-modified phenolic resin is fabricated and appropriate coated tools are selected. The SEM images of the wire saw folded before and after were discussed. According to the experiences of this experiment, problems of the resin bonded diamond we probably met in the practical production were answered.