These questions are for MFMT 201, in addition to some of those shown on the MFRG 317 sheets.

1. What is meant by 'machinability' and what factors affect the machinability of a workpiece?

2. Show with the aid of a sketch the location of the two zones where heat is generated in a single point orthogonal cutting process. State the common assumption about where the heat goes to and the effect of speed on this.

3. Explain with the aid of sketches the different effects that occur when machining low alloy low carbon steel with a single point high speed steel cutting tool at different cutting speeds.

4. What are the advantages and disadvantages of the following materials when used as cutting tools:
High speed steel (HSS), carbides, ceramics and cubic boron nitride?

5. A HSS tool when cutting a plain carbon steel at a speed of 45.766 m/min has a life of 15 minutes. If C = 60 for this combination of tool material and workpiece, determine 'n' and the tool life at a cutting speed of 35 m/min.
If this tool was cutting a chip 3 mm wide with an undeformed chip thickness of 1.5 mm, what machine power is required assuming the specific cutting energy, E₁ = 1.5 W.s/mm³ and the machine tool has an efficiency of 70%
(n = 0.1, 219 minutes, click here for solution and 5 kW).

6. A carbide cutting tool has a life of 1 minute when cutting at a speed of 1000 m/minute. If the tool life is 10 minutes at a cutting speed of 500 m/minute, what is the Taylor tool life exponent 'n'.
(n = 0.301).

7. Describe a process for drilling long (100 mm) small diameter (2 mm) holes in a heat resisting nickel alloy turbine blade.

8. Describe with the aid of a sketch what is meant by a forming limit diagram and explain how such a diagram is obtained.

9. In sheet metal forming, what is anisotropy and explain its significance.

10. Describe the characteristics and relative merits of hot and cold working.

11. Describe an experiment to determine the constants K and n in the expression for the cold working flow stress of a metal and describe how the results are processed.

12. Summarise the key differences between fusion welding and brazing. Why is MIG welding very popular for a wide range of applications?

David J Grieve, 17th March 2009.