Tech Tip: Reducing Chatter & Vibration in End Milling

Axial contact points play a significant role in reducing vibration and chatter during machining processes.  Finding the correct axial cutting depth that corresponds to a specific number of contact points can help achieve stable cutting conditions. The contact points are established based on the ratio of the axial depth of cut and the pitch of the end mill helix.

• Select end mills with a larger core diameter for better stability.
• End mills with a small circular margin can improve dampening.
• Use the shortest possible overhang from the spindle nose to the tool tip.
• Where possible, use stub length end mills to reduce deflection.
• Ensure tool holders are balanced to minimize vibrations including when used with Hydroforce™
  
• Rework the fixture to hold the workpiece more securely.
• Reprogram the tool path to direct cutting forces into stiffer parts of the workpiece.
• Experiment with spindle speeds and adjust the feed rate accordingly.

Chatter often occurs when machining corners due to increased engagement and cutting forces. To mitigate this:

• Use circular interpolation to create a larger corner radius than specified in the part print.
• Remove remaining stock with a smaller end mill using circular interpolation.

• Ensure starting speeds and feeds are correct for the material and cut.
• Sometimes, increasing the feed or chipload per tooth can help.
• Make the workpiece as rigid and secure as possible.
• Minimize the distance between the workpiece and spindle.
• Select an end mill with more flutes for smoother cutting.
• Ensure the tool run-out is within acceptable limits.
• Verify that the cutting face, relief, fluting and helix angle are suitable for the material.
• If using conventional milling, try switching to climb milling.

By following these tips, you can significantly reduce chatter and improve the quality of your milling operations.

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