What problems can affect endmills machining results?

The wear of solid carbide end mills is mainly concentrated in cutting edge wear, peripheral edge wear, boundary wear, bottom edge wear and rake face wear.

Edge Wear and Boundary Wear

The size of edge wear and boundary wear play a decisive role in cutting tools life.

1. The reason for boundary wear: due to the oxidation of the heating part of the cutting edge and the boundary part of the air.

2. Causes of blade wear: The cutter must bear the cutting load in two directions of the peripheral edge and the bottom edge at the same time.

3. The reason for the wear of the bottom edge: the outer circumference of the tool decreases toward the center, and the bottom edge part has a core digging angle. Reducing the outer peripheral rake angle (radial edge angle) will reduce the cutting sharpness. However, the depth of rake face wear is less than that of boundary wear and edge wear. Therefore, the impact on tool life is small.

Failure Modes and Solutions

Next, let’s focus on how to solve these failures and make your processing more successfully.

First, the significant peripheral edge wear is caused by excessively high cutting speeds, low feed rates or up-cut milling.

There is following solutions for your reference.

1. Properly reduce the cutting speed.

2. Properly increase the feed speed.

3. Confirm whether it can be changed to climb milling.

Second, the chipping is caused by excessive cutting speed, high feed rate, low end mill tip rigidity and insufficient collet setup.


1. Reduce the cutting speed.

2. Reduce the feed rate.

3. Use more rigid endmills.

4. Tighten the clamp.

Third, the reason for sticking is due to the chemical reaction of cutting heat to soften the workpiece or the low cutting speed.

Using cutting fluid, increasing the supply of cutting fluid, changing the coating material and increasing the cutting speed all can solve this problem properly.

In addition, the reasons why breakage is due to high feed rate, low end mill rigidity, excessive overhang, or excessive depth of cut.

The methods to prevent breakage have reduce the feed rate, use a rigid end mill, adjust the overhang to the minimum value within the allowable range, and reduce the depth of cut.

What's more, why there is poor surface roughness is that the tool vibrates too much or feed speed is high, or the cycle feed is large or chip removal is poor.

You need to reduce tool vibration, feed rate and the cyclic feed, use blowing method and increase the supply of cutting fluid.

Last but not least, there is sometimes poor straightness of the processed surface happened. It is caused by excessive depth of cut, too high feed rate, large helix angle.  Treatment method can be reducing the depth of cut, reducing the feed rate or use an end mill with a smaller helix angle.

Hope through these troubleshooting methods, your cnc machining can have better effects.

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