To determine whether the end mill needs to be replaced, the following criteria can be used:
First, the degree of wear
The life of end milling cutter is determined based on some form of tool wear reaching a predetermined value. The commonly used criteria include the width of the wear band of the back cutter face (VB) and some depth of the wear of the front cutter face (KT). When the rear tool surface is evenly worn, the average value on all tool teeth reaches 0.3mm. In the case of local wear, the maximum value on any tool tooth reaches 0.5mm, and the tool can be replaced.
Falling edge is also an important basis for determining whether the end mill needs to be replaced. When the edge breakage occurs, it can be treated according to local wear, with VB3=0.5mm as the tool life end point. Severe edge breakage and delamination can also be used occasionally as a criterion, but destructive damage caused by human factors cannot be used as a criterion for the end of tool life.
Second, processing quality
When the end mill is worn to a certain extent, the processing quality will be significantly reduced, which is manifested by the increase of workpiece surface roughness and the reduction of dimensional accuracy. At this time, even if the tool has not reached the wear limit, it should be considered to replace the new tool to ensure the processing quality.
Third, cutting performance
With the increase of end mill wear, its cutting performance will gradually decline, which is manifested as the increase of cutting force, the increase of cutting temperature, and the decrease of cutting speed. When the cutting performance can not meet the processing requirements, the tool should be replaced in time.
Fourth, use experience
According to actual experience, when the end mill appears cutting instability, vibration, noise increase and other phenomena, it is often a serious performance of tool wear. At this point, the tool should be stopped and checked, and replaced if necessary.
In summary, to determine whether the end mill needs to be replaced, factors such as wear degree, processing quality, cutting performance and use experience should be considered comprehensively. In actual operation, the tool should be checked and maintained regularly to ensure that the tool is in good condition to improve processing efficiency and product quality.
