1. For large positive back rake angle, tool will be
a) Weaker
b) Stronger
c) Smoother
d) Harder
Explanation: With the increase in positive back rake angle, lip angle decreases and tool tip become thin.
2. For large negative back rake angle, tool will be
a) Weaker
b) Stronger
c) Smoother
d) Harder
Explanation: With an increase in negative back rake angle, lip angle increases and tool tip become thick and hence the strength of tool will increase.
3. Which of the following will give better chip flow?
a) Positive back rake angle tool
b) Negative back rake angle tool
c) Zero back rake angle tool
d) None of the mentioned
Explanation: With positive back rake angle, lip angle decreases and space for chip flow increases and hence it will give better chip flow.
4. Which of the following will give large friction during chip flow?
a) Positive back rake angle tool
b) Negative back rake angle tool
c) Zero back rake angle tool
d) None of the mentioned
Explanation: With negative back rake angle, lip angle increases and space for chip flow decreases due to which it offers large resistance to chip flow.
5. Negative back rake angle is given for machining of:
a) Brittle and hard material
b) Soft material
c) Ductile material
d) Soft and ductile material
Explanation: Brittle material has smaller amount of chip flow and are very strong. As negative back angle tool are very strong, hence these are used for machining of brittle and hard material
6. Which of the following will give maximum chip flow during machining?
a) Hard material
b) Ductile material
c) Brittle material
d) All of the mentioned
Explanation: Brittle material breaks very easily due to which they have maximum chip flow.
7. With an increase in rake angle of tool, tool life will
a) Increase
b) Decrease
c) Remains constant.
d) First increase then decrease
Explanation: With an increase in rake angle chip flow rate increases and hence the heat generated is carried away with chips at faster rate due to which tool life increases. For large back rake angle, tool become very thin and its life decrease.
8. For machining of carbide material which of the following tool will be preferred?
a) Large positive rake angle tools
b) Large negative rake angle tools
c) Zero rake angle tools
d) Small point angle tools
Explanation: Carbide materials are very hard hence strong tool is required for their machining. Tools with large negative back rake angle are stronger.
9. With an increase in side cutting edge angle keeping width of cut constant, depth of cut will
a) Increase
b) Decrease
c) First increase then decrease
d) Remains constant
Explanation: Depth of cut is directly proportional to cos of side cutting edge angle, hence it decreases with increase in side cutting edge angle.
10. What is the optimum value of side cutting edge in degrees for maximum tool life?
a) 20
b) 22
c) 25
d) 30
Explanation: At 30 degree chip removal rate and strength of tool are optimum and hence tool life will be maximum.