When wear land reaches a certain level as a function of diameter and type of end mill (for values see table to right).
When the chips change to a blue color.
When dimensional accuracy is not acheived.
When large burs appear on the edge of the workpiece.
When smoke and an unusual noise appear.
When motor amperemeter levels increase.
|Maximum Permited Land Wear before Resharpening|
Feed per Tooth:
IPT= IPM ÷ Z ÷ RPM
RPM = SFM x 3.82 ÷ D
IPM= IPT x Z x RPM
SFM= D x 0.26 x RPM
Inch (Feed) per Revolution:
IPR (FR) = IPM ÷ RPM
Metal Removal Cubic Inches per Minute:
MR= IPM x RDC x ADC