The number of defective produced by a six sigma process (in Parts per million) is

Grinding ratio is defined as

The binding material used in cemented carbide cutting tools is

The thickness of a plate is reduced from $$30$$ $$mm$$ to $$10$$ $$mm$$ by successive cold rolling passes using identical rolls of diameter $$600$$ $$mm.$$ Assume that there is no change in width. If the coefficient of friction between the rolls and the work piece is $$0.1,$$ the minimum number of passes required is