Cutting performance of laser assisted diamond turning of calciumfluoride with different crystal orientations
Charan Bodlapati, Di Kang, Jayesh Navare, R. J. Turnbull, Yuxiang Zhong, Hossein Shahinian
Abstract
Single point diamond turning of single crystal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">C</mml:mi> <mml:mi mathvariant="normal">a</mml:mi> <mml:mi mathvariant="normal">F</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> using the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mtext>µ</mml:mtext> </mml:math> -LAM process is studied. We focus on how crystal orientation of the workpiece can influence tool wear and efficiency of the cutting process. Cutting experiments were performed on single crystal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">C</mml:mi> <mml:mi mathvariant="normal">a</mml:mi> <mml:mi mathvariant="normal">F</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>100</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>111</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> , and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>211</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> crystal orientations. The tool failed at the smallest cutting distance for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>111</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> crystal orientation, whereas tool failure on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>100</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> orientation occurred at the longest cutting length. Tool life for cutting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>211</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>111</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> crystal orientations was found to be 92% and 67%, respectively, of that of tool life during cutting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo fence="false" stretchy="false">⟨</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>100</mml:mn> </mml:mrow> <mml:mo fence="false" stretchy="false">⟩</mml:mo> </mml:math> orientation. To explain the results obtained, an anisotropic model based on Schmid’s law was used. It is shown that an inverse correlation between the resistance to plastic deformation and maximum cutting distance without inducing any brittle fracture can be established.