Experimental Study On Force And Surface Quality Of Photoelectric Material With Fixed Abrasive Diamond Wire

With the development of optoelectronic industry,LED has been used widely.Sapphire and SiC,as the substrate of the LED,are widely used in semiconductor lighting,military,aviation and other fields.As the hard and brittle materials,the sapphire and SiC are difficult to saw.If the surface quality can't be guaranteed,it will reduce the quality and efficiency of follow-up processing.So to study the sawing process of sapphire and SiC is necessary.In this paper,the sawing forces and surface qualities of A plane sapphire,C plane sapphire,4H-SiC and 6H-SiC were studied by single-line reciprocating wire sawing.The effects of process parameters and sawing position on tangential force,sawing specific energy,surface roughness,surface three-dimensional morphology and micro-morphology,flatness were analyzed.Their forces and surface qualities were compared,and the sawing characteristics of different materials were analyzed.The main results of the paper are summarized as follows:1.The process of sawing two different materials all have experienced from the unstable sawing area to stabilize sawing area,and the unit length sawing force of unstable sawing area is significantly greater than the unit length sawing force of the stability of the cutting area.The surface roughness along the feed direction of the unstable sawing zone is also significantly higher than the surface roughness of the stable sawing area.In terms of morphology,the sawing surface of the unstable zone is markedly raised.2.The unit length sawing forces of two different materials all increase linearly with the increase of the feed speed,and decrease with the increase of the wire speed,but the degree of decrease is gradually weakened.3.The sawing position has a significant effect on the tangential force.The sawing force of SiC at different sawing depths has a good correspondence with the contact length of the wire saw and the workpiece.However,the correspondence of the sapphire is not obvious,and the sawing force decreases linearly with the increase of the sawing depth in the second half of the sawing.4.The tangential force and sawing specific energy of 6H-SiC are the largest,followed by 4H-SiC and A plane sapphire,and the sawing force and the sawing specific energy of C plane sapphire are minimal.The difference in sawing force and sawing specific energy is closely related to the elastic modulus and fracture toughness of the material.5.The surface roughnesses of two materials in the feed direction are greater than the surface roughnesses in the wire speed direction.The surface roughness in the feed direction is: Ra(C plane sapphire)> Ra(A plane sapphire)> Ra(6H-SiC)> Ra(4H-SiC).The effect of process parameters on the surface roughness of C-plane sapphires is obviously.6.The sawing surface morphology of two materials has obvious sawing ripple features,which are caused by the acceleration and deceleration of wire saws.It is found that the sawing surfaces are composed of crushing zone,plow area and smooth area,and a large number of crushing zones show that these four materials are still mainly brittle fracture.Compared to sapphire,the smooth surface of SiC is more visible.The effect of process parameters on the microstructure isn't obviously.7.The overall shapes of the wafers are raised at sawing in and out positions and down at the center position.And the process parameters have significant impact on the shapes of the wafers.