Taylor Formula for Tool Life – Relationship between Cutting Speed and Tool Life with Graph
Taylor tool life equationIt is observed that the higher cutting speed shorter the tool life. This relationship between cutting speed and tool life is given by Taylor formula. This formula gives fairly good results. Tylor equation is restricted to very narrow range of cutting process parameter because this equation does not take all affecting parameter into consideration.
VTn = C
V = Cutting speed in meter per/ minute
T = Tool life in minutes
n = an index related to cutting tool material
For high speed steel tools, n= 0.1 to 0.5
For tungsten carbide tools, n= 0.2 to 0.4
For ceramic tools, n= 0.4 to 0.6
C = a constant. It is numerically equal to the cutting speed that gives tool life of one minute (C = V*1n = V)
Tool life testing - Cutting speed Vs Tool life plottingIn order to plot the relation between tool life and cutting speed, the tool is operated to failure at different cutting speed. The obtained result is then plotted. The obtained graph will be a parabolic decrease in tool life with an increase in cutting speed. This relationship also plotted on a log-log graph, then it plots as straight line as shown in the figure.
At lower cutting speed a slight increase speed results in a large change in tool life. At higher cutting speed the tool life is almost the same. For the same tool life, the high cutting speed gives better cutting properties and productivity.
🔗Types of tool wear - Flank wear, Crater wear, Corner wear
What are the factors which influence the cutting speed permitted by the tool?The following factors will influence the cutting speed
- Cutting tool life
- Types of the machining process
- Material of tool and material of workpiece
- Tool geometry, size of the tool shank.
- Rate of feed and depth of cut.
- Types of cutting fluid used
- Maximum permissible amount of wear