Lesson 70 of Industrial Engineering ONLINE Course.
Lesson 71. Selecting a Machine for the Operation
Recommended Textbook (Process and Operation Planning, Gideon Halevi, 2003)
Chapter 9. How to Select Cutting Speed
1 Introduction
Cutting speed and time taken to do the machining are related as formula for turning machine time = (L/nf) and n (spindle rpm) is determined by the cutting speed and diameter of the work. L is the length of cut and additional travel and f is feed per revolution.
2 Source for Selecting Cutting speed
2.1 Machining data handbooks
2.2 Machinability ratings
2.3 Technical books
2.4 Tool manufacturers
2.5 Machinability computerized systems
Sources for initial selection of cutting speed and other cutting parameters are machining data handbooks, machinability ratings given to materials, other technical books and articles, recommendation of cutting tool manufacturers and distributors. Now, even databases having machinability details and recommendations are available. Industrial engineers have to be on the look out for possible improvement in the productivity through further increase in cutting parameters and must be ready to experimental with possibilities and use the best cutting conditions. Continuous improvement is each feature that contributes to productivity improvement has to be periodically monitored and examined to identify opportunities for improvement.
Industrial engineers have to encourage sales representatives to meet them and inform them of technical developments in the operations they employ in their organization.
3. Cutting Speed Optimization
3.1 Taylor equation
The cost data and Taylor tool life equation are used to find optimal tool life.
3.2 How effective is cutting speed optimization?
In the end, cutting speed decision is economic subject to technological constraint.
3.2.1 Tool life definition
ISO standard 3865 defines the values of tool wear.
3.2.2 Lot size effect
The cutting speed can be modified slightly so that if it is possible the tool life is equal to the batch size.
3.2.3 Economic cutting speed for machining a part
If possible the number of parts after which a tool has to be changed is made the same for all operations.
4 Data for the Extended Taylor Equation
Table 1 in the chapter of the book gives coefficients for various parameters of the extended Taylor equation for 37 groups of materials. (Industrial engineers have acquire the book of Gideon Halevi for their company library. Actually, IE departments must have a library of their own).
Updated on 26 July 2020
20 July 2020.
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