Development Of Twisted Pair Resin Bonded Diamond Wire Saw

KDP crystal is a kind of nonlinear optical material with good comprehensive performance.The large-size and high-quality KDP crystal is widely used in the field of high-power laser,which puts higher requirements on the processing of KDP crystal.In the process of slicing a large-sized crystal,as the sawing depth increases,it is difficult for the cutting fluid to flow into the sawing area,causing the temperature of the sawing area to rise,and the chips and falling off during the sawing process.It is difficult to discharge the abrasive grains,which is easy to damage the crystal and wire surface,affecting the surface quality of the wafer and the service life of the wire.The resin bonded diamond wire saw has good flexibility and high sawing quality.The spiral structure of the twisted pair fixed abrasive wire saw can improve the inflow of the cutting fluid.In this paper,the two resin bonded diamond wire saw are twisted together to make a twisted pair resin bonded diamond wire saw.The chip flute is increased,the sawing efficiency is improved,and the damage of the wafer surface by the falling abrasive grains and chips is reduced,which meets the requirements of large-size,high-quality KDP crystal chip processing.The main research work of this paper is summarized as follows:The main production parameters of the twisted pair resin bonded diamond wire saw were determined,and the chip pocket volume,the effective number of abrasive grains involved in sawing and the tension were calculated.The main production parameters of the twisted pair resin bonded diamond wire saw are:diameter D,pitch h,helix angle α,chip pocket volume Vcp,abrasive grain density Ns,tension 2F.By establishing the chip pocket model of the twisted pair wire saw,the formula for calculating the volume of the chip pocket is determined.The influence law of the pitch and the diameter of the single wire on the chip pocket is obtained.By establishing the sawing model of the twisted pair wire saw,the formula for calculating the effective number of abrasive grains involved in sawing is determined.The influence law of pitch and the abrasive grain content on the effective number of abrasive grains involved in sawing are obtained.Through the analysis of the bending stress and the tensile stress of the twisted wire,combined with the strength calculation,the calculation method of the maximum tension of the twisted pair wire saw is determined.The material was selected,resin bonded single-wire saw was fabricated,.and twisted pair resin bonded diamond wire saw was developed.The SWPB piano wire with a diameter of 0.16mm is selected as the matrix,the diamond abrasive grain size is 20μm-30μm,and the resin binder is phenolic modified epoxy resin.Three sets of resin bonded diamond single-wire saw with abrasive content of 450mg/ml,550mg/ml and 650mg/ml were prepared.The quality and diameter of the single wire saw,the exposed height and density of the abrasive grain were evaluated.On the basis of the resin bonded single-wire saw,three sets of single wire saw were respectively twisted into 9 sets of twisted pair wire saw with pitch of 4mm,6mm and 7.5mm.The quality of the twisted pair wire saw was evaluated from the appearance,diameter and pitch.The orthogonal test of KDP crystal sawing process was designed,and the fabrication parameters of the twisted pair resin bonded diamond wire saw were optimized by orthogonal test.The self-made 9 sets of twisted pair resin bonded diamond wire saw was used to carry out the experiment of sawing KDP crystal.The pitch and abrasive content were used as the analysis factors,and the 2 factor 3 level orthogonal test was used to analyze the pitch and grinding.Determine the best overall performance pitch and abrasive content in the study area.Compared with the sawing performance of the single-wire saw,it is found that the sawing efficiency is significantly improved,the kerf width is reduced,and the machined surface roughness is substantially the same as that of the single-wire saw.