Improvement of wire marks on the surface of Si3N4 ceramics cut by diamond wire saw

Abstract

The presence of wavy wire marks on the cut surface of silicon nitride (Si3N4) ceramics reduces the mechanical properties of the slices and increases the workload of subsequent grinding and polishing processes. To improve the wire marks, a workpiece reciprocating movement-assisted diamond wire sawing (RMA-DWS) technology is proposed in this paper. While diamond wire sawing the Si3N4 ceramics, the workpiece is moved back and forth in the direction of the saw wire movement to assist in sawing. Single factor and orthogonal experiments were carried out to analyze the characteristics of the surface created by this sawing technology. The effects of workpiece reciprocating movement distance, workpiece reciprocating movement speed, saw wire speed and feed speed on the sawn surface morphology, surface roughness Ra and wire marks PV value, as well as the primary and secondary relationships of the effects, were investigated. And the optimal parameter combinations were explored. The results show that within the range of process parameters studied in this paper, the surface morphology of Si3N4 ceramics slices shows a comprehensive effect of material ductility and brittleness removal, the RMA-DWS technology can improve wire marks on the slice surface. Surface wire marks PV value can be reduced by increasing the workpiece reciprocating movement distance and saw wire speed, reducing the feed speed, while increasing the reciprocating movement speed of the workpiece, the PV value shows a trend of first decreasing and then increasing. The variation amplitude of surface roughness Ra value is not significant, and the variation trend is roughly similar to the change trend of PV value. It was determined that the experiment with the process parameters combination of 0.1 m/min feed speed, 90 mm workpiece reciprocating distance, 15 mm/s workpiece reciprocating speed and 1400 m/min saw wire speed yielded the optimal result, significantly improving the wire marks of the sliced surface. The results of this paper provide ideas for the development of sawing wire marks improvement technology.