Ripples Along the Entire Length of a Cut

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. 

Unbalanced Tool

Tools must be balanced to G2.5 or better for applications that exceed 10,0000 RPM. At high spindle speeds, the vibration caused by an out-of-balance tool causes vibration that will damage the spindle and cause surface finish issues. Balanced tooling is not required at spindle speeds below 10,000, but it is recommended to prevent surface finish issues. 

Corrective Actions:

Balance the tool holder with the cutting tool in it. If you cannot balance the tool assembly, replace it with one that you can balance.


The Tool or Tool Holder May be Too Long for the Application.

Longer tools are less stable than shorter tools. Always use the shortest tool possible, and remember that a 10% reduction in the length-to-diameter ratio results in a 25% increase in tool stiffness.

If the cut chatters and reducing the tool length is practical, reduce the tool length to use the shortest tool and tool holder possible for your application.

Unless absolutely necessary, the tool's stick-out from the holder should not be more than 3 times longer than its diameter.

In some cases it may be necessary to use an extended tool, machining a deep pocket for instance. In these scenarios you must reduce the load on the tool by reducing the depth-of-cut, width-of-cut, RPM or feedrate to maintain a stable cut. 

A Machine Accessory Causes Vibration

Machine accessories such as the tool changer, chip conveyor, or chip auger can cause vibration during the cut.

Make sure that the chip conveyor or auger is turned off during finish cuts. Command M33 to do this in a program.

The side-mount tool changer pre-stages the next tool to reduce cycle time. If the carousel is in motion, the resultant vibration can affect a finish cut.

  • Program a Tnn without M06 to pre-stage a tool before the finish cut starts.
  • Put an optional stop (M01) in the program, after the finish cut blocks and before the next tool change. This prevents look-ahead from staging the next tool while the finish cut runs.

Incorrect Servo Gain Parameters

The servo P, I, and D gain parameters for an axis motor may be set incorrectly. If the servo loop is not tuned correctly, vibration and servo noise can lead to surface finish issues.

The P, I, and D gains are tuned during the assembly process and should not be changed from their original values.  


Vibration from External Sources

Vibration from other machines, shop equipment, heavy machinery, passing trains, etc. can cause finish problems.

Corrective Actions:

Stop other machines, forklifts, overhead cranes, etc. during cutting. This may be helpful if the machine’s foundation is inadequate.

Inadequate Foundation

The machine must sit on a solid and stable foundation. Refer to Pre-Installation Information for a full description of the foundation requirements.

If the foundation is badly cracked, move the machine to a location with a solid foundation, or repair the foundation.

The machine should sit on one continuous slab of reinforced concrete. If the machine straddles more than one slab, you may need to move the machine to a single, continuous slab.

Example of a Machine Set Across Multiple Concrete Slabs



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.