b$)$ Write down the part program for the part $($Fig$.$ B$)$ to be made on CNC milling machine. The channel of $8$ mm

diameter, $5$ mm deep along the rectangular path shown $($ABCDA$).$ A circular channel with radius of $20$ mm starting at

pt$.$ E ending at pt$.$ F with $4$ mm wide and $6$ mm deep. Take stock size as $120$ x $120$ x $15($mm$).$