The machining accuracy and surface roughness of mono-crystalline silicon regarding wire lag and wire stiffness of endless diamond wire

The endless diamond wire is a special application of diamond wire cutting. The loss of wire machining accuracy will cause the fluctuate and unflat surface, which will cause drum shape error with large dimension in the middle of silicon ingot and small dimension on the head and tail of silicon ingot. In this paper, based on the phenomenon of drum shape error processed by a single wire, the factors affecting the machining accuracy, including the stiffness of wire web, tension, and fluctuation of wire were studied. The reason for the influence of machining accuracy during the endless diamond wire sawing process was mainly determined by the position of diamond wire. In view of the wire-lag effect of diamond wire, the definition and evaluation method of the stiffness of the endless diamond wire web were proposed. It was found that the formation of wire bow, especially the lateral wire bow induced by the lateral force, was the main reason causing the machining accuracy. In view of the evaluation of machining accuracy, the flatness evaluation method could be used instead of the current method of extreme deviation analysis, which could provide more comprehensive evaluation of the sawing accuracy.