loy 2016te 1 07-Mec-A4/May 2016 P 2/5 PART A: Choose any two (2) problems from p
ID: 1867355 • Letter: L
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loy 2016te 1 07-Mec-A4/May 2016 P 2/5 PART A: Choose any two (2) problems from part A. 0% a) List the two principal functions of cutting fluids at low cutting speeds and (b) discuss at least two List the two principal functions of cutting fluids at high cutting speeds and (b) discuss at least two i In a lathe turning operation, chatter sets in during machining a particular part (a) What will be its mechanisms by which they fulfill these functions. mechanisms by which they fulfill these functions. iecthe sn os woue manifestation (list at least two) and (b) indicate the steps you would take to identify the cause of chatter jeA surface turned with a tool of 1-mm nose radius has unacceptably high roughness. To improve the finish, suggest a change to the (a) process and (b) tool, and indicate the unintentional consequences of such changes (assume that no tool pickup affects roughness)Explanation / Answer
a) The primary function of cutting fluid at low cutting velocity is to lubricate cutting process, make chip removal easy and increase tool life.
b) The primary function of cutting fluid at high cutting velocity is to cool the workpiece, increase tool life, surface finish and prevent workpiece from thermal deformation.
At high cutting velocity the temperature of tool and workpiece goes up, so to reduce thermal deformation of the workpiece and tool cutting fluid is used. Thus increases tool life.
c) Chatter is a process induced vibration. It results in easiness on the workpiece. A regular chatter marks are seen on turned surfaces.
To avoid chatter
Make lathe, tool and workpiece as rigid as possible
and choose tools that include vibration damping facilities
d) To get better surface finish reduce nose radius of tool by grinding and decrease feed rate. Thus is beacause surface roughness is proportional to cube root of feed and inversilly to nose radius.
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