(i) What is High-Efficiency range or High-Economic range (Hi-E) in machining?
(ii) Why is it called so?
(iii) The results of machining steel with two grades of tool materials are given below:
|
Tool
|
Taylor’s
Exponent
|
Cutting speed for one minute too life, m min
|
|
A
|
0.20
|
100
|
|
B
|
0.25
|
120
|
What are the standard tool life equations for these two materials?
(iv) For a 180 minute tool life, which tool is recommended and why?
(v) If the tool grinding and changing time is 15 minutes, which cutting speed for the tool ‘A’ has to be chosen from the two available speeds, 45 m/min, 50 m/min ?