What are the commercial applications of zero rake angle ??

Answer 1

Perhaps you could clarify the context. You may mean the angle of a cutting tool relative to the workpiece in machining. Machinists use negative rake, zero rake, and positive rake. Different rakes are used for different situations and desired outcomes. Different choices lead to different surface finishes and chip styles. The combinations are many--it's best to look at a machining reference book in order to choose which option is best for your desired outcome.