Mill Tool Life Troubleshooting - Endmill & Shellmill

The Tool is Dull

It is normal for tools to wear over time. In a stable machining process the tool wear is predictable. This will allow you to use the Tool Life Management systems that come standard in your Haas control. The tool life information can be input in to the Haas control so that your operator will be alerted to replace the tool before the dull tool negativity effects your machining process. 

Refer to the Tool Life Management section for details on how to use these systems. 

The RPM & Feedrate are Not Optimal

If the RPM and feedrate are not set correctly excessive heat will be produced, this heat will damage the tool and cause premature wear, furthermore it may lead to chatter or surface finish issues.  

Make sure that your feedrate and RPM are correct for the tooling and the workpiece material. Refer to your tooling manufacturer's documentation for the best cut parameters to use.

A cutting speed (Vc) that is too high has the most detrimental effect on your tool life. 

Cutting Speed Too High

  • Rapid flank wear
  • Poor finish
  • Rapid crater wear
  • Plastic deformation

Cutting Speed Too Low

  • Built-up edge
  • Dulling of edge
  • Uneconomical
  • Poor surface finish


The feed rate (fn) has a moderate effect on the tools life.

Feed Rate Too Light

  • Stringing chips
  • Rapid flank wear
  • Built-up edge
  • Uneconomical

Feed Rate Too Heavy

  • Loss of chip control
  • Poor surface finish
  • Crater wear
  • Plastic deformation
  • High power consumption
  • Chip welding
  • Chip hammering

Cut Size Too Large

If the cut is too deep or too wide, the cutting forces can cause the tool to break or wear prematurely.
Make sure that your depth-of-cut and radial engagement are correct for the tooling, and for the workpiece material. Refer to the tooling manufacturer's documentation for the best cut parameters to use.

The depth-of-cut (ap) has a minor effect on the tool life.

Too small

  • Loss of chip control
  • Vibration
  • Excessive heat
  • Uneconomical

Too deep

  • High power consumption
  • Tool breakage
  • Increased cutting forces

Coolant Issues

Incorrectly aimed coolant nozzles or obstructions in the stream can prevent coolant from reaching the cutting area. Adjust your coolant nozzles to deliver coolant to the cutting area.

Be sure to use the recommended coolant mixture concentration in your applications. If your concentration is too lean, the reduced lubricity can negatively affect your tool life and surface finish.
There are many different coolants for different applications and materials. Contact your coolant dealer for advice.

Refer to the Machine Tool Coolant Series page for videos and articles about maintaining your coolant system.

Excessive Endmill Runout - Mill

Excessive runout causes an inconstant load on the tool as it rotates. This can lead to premature tool wear and issues with accuracy and surface finish.

Tool runout should not exceed 0.0003" (0.076 mm). To check the tool runout, place a dial indicator on the tool, and then rotate the spindle by hand. 

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.