For machining my cavity I tried the facemill 4 round tips instead of HSS or carbide end mills due to the fact that i had to create a big pocket so a facemill will 50mm dia looked the right choice.

I know that facemill are not best for pocketing so I created a bore throughout my cavity so that my facemill's all for tips are not in contact while taking the depth of cut. So i generated a programme which would take the depth in the empth bore in the centre of the workpiece in the empthy bore and then only one side of the mill comes in contact woth the workpiece.
However this was unsucessful even when i took a depth of 0.3, the mill made enormous noise and the surface of the workpiece had deep lines on it. my spindle was at 800 and feed was also 800 mm/min,

waiting for ideas.