Mechanical Engineering - Production Engineering - Discussion

END CUTTING EDGE ANGLE:

End cutting edge angle prevents wear on tool and workpiece surface and is usually 5°15degrees.

Effect of end cutting angle:

Decreasing the end cutting edge angle increases cutting edge strength, but it also increases cutting edge temperature.

Decreasing the end cutting edge angle increases the back force and can result in chattering and vibration while machining.

Small end cutting edge angle in roughing and large angle in finishing are recommended end cutting edge angle.

As I have studied cutting edge angles do not have any effect on cutting forces, power and other factors so with the help of these factors it will be wrong to decide the tool life.

If one will consider the formula of roughness

Peak to valley roughness (h) = [f/{tan (SCEA)+cot(ECEA)}}.

Where,
f is feed.
SCEA is side cutting edge angle.
ECEA is end cutting edge angle.

So as EDEA will increase cotEDEA will decrease and in turns roughness will increase Thus tool life will decrease.

It is the angle which prevents interference as the tool enters the work materials. (Normally 15 - 30 degree).

At its increased value it will have more of its length in action for a given depth of cut.

At its increased value it produce thinner and wider chip that will distribute the cutting heat. (Increase tool life).

If you increase the rake angle the force developed will be less simultaneously power consumption less and tool life increase but this is limited up to 45 degrees. But with increase in rake angle the strength of the tool reduces. Experimentally with increase in 1 degree rake angle there is 8 to 10% reduction in forces.

The main function of end cutting edge angle is to prevent the trailing front cutting edge of the tool from rubbing against the work. The end cutting edge angle varies from 8 to 15 degree. A large end cutting edge angle decreases tool width which in turn weakens the too and decreases tool life.

So answer is "B".

If End cutting edge angle increases, simultaniously it decreases the lip angle or wedge angle of the tool.

So, due to other factors like stress concentration, heat dissipation will decrease the tool life.

If I am wrong then let me know.

Yeah, it should increase because when the cutting edge angle increases the resisting area of tool decreases hence the strength of tool decreases so less force and power required then tool wear reduces and the tool life increases.

Simple the angle between flank face and vertical line from the cutting edge will decrease so its thickness will reduce and hence it will resulting the weakness of tool.

According to Rs Khurmi,

If larger cutting edge angle increases it tool life.
If side cutting edge angle increases produces chipping and decreases tool life.

Larger end cutting edge angle increases tool life. And side cutting edge angle produces chipping and decreases tool life. So answer B is wrong.