Experimental study on normal force of cutting sapphire with multi-wire swing reciprocating wire saw

Abstract

Multi-wire swing reciprocating sawing technology is the main machining method used to cut sapphire crystal bars into wafer substrates, while normal force is an important index that reflects the processing stability. In this paper, the normal force（\begin{document}$ {F}_{\mathrm{n}} $\end{document}）during multi-wire swing reciprocating wire saw cutting sapphire crystal bars was measured, and the change in normal force at different positions and cutting depths of the sapphire crystal bars was tracked. The influence of various process parameters on the stability of the machining process was tracked by using the rangeability of normal force（\begin{document}$ \mathrm{\Delta }{F}_{\mathrm{n}} $\end{document}）as the index. The experimental results show that \begin{document}$ {F}_{\mathrm{n}} $\end{document} is closely correlated with the reciprocating motion of the wire saw and the rocking motion of the workpiece, and Δ\begin{document}$ {F}_{\mathrm{n}} $\end{document} in the front of the sapphire crystal bar is significantly different from that in the middle and back. Process parameters such as the wire saw speed（Vs）, maximum swing angle (θmax), single piece wire consumption (Md), tensioning force (Fw), and total cutting time (T) have different effects on Δ\begin{document}$ {F}_{\mathrm{n}} $\end{document}. The fluctuation degree of Δ\begin{document}$ {F}_{\mathrm{n}} $\end{document} is closely related to the wear of the wire saw.

Keywords

• multi-wire swing reciprocating sawing technology
• sapphire
• normal force
• wear and tear
• machining stability