Chatter (vibration)

?Likely causes

• Long tool overhangAgreed by 2+ makers^{[1][2][3][4][5][6]}
• Insufficient rigidity of workpiece or tool mounting (weak clamping, thin-walled part with poor support)Agreed by 2+ makers^{[1][2][3][7][8][5]}
• Play or insufficient rigidity in the machine or spindleAgreed by 2+ makers^[3][9][5][2]
• Cutting conditions (speed, feed, depth of cut) are not suitableAgreed by 2+ makers^{[8][9][10][5][6]}
• Cutting speed is too highAgreed by 2+ makers^[5][6][11]
• Feed or depth of cut is too small, so cutting force is unstableAgreed by 2+ makers^[1][5][6]
• Rotation speed coincides with the natural frequency of the machine and tool system, causing resonanceOne maker^[5][6]
• Insert geometry with high thrust force (radial force), such as a large corner radius or small lead angleAgreed by 2+ makers^[1][3]
• Too many teeth cutting at the same time (regenerative chatter)Agreed by 2+ makers^[7][5][6]
• Dull cutting edge (negative geometry, large honing, progressing flank wear) causes high cutting forceAgreed by 2+ makers^[1][3][5]
• Rake angle or clearance angle is too large, so the edge is weakOne maker^[5][6]

✓Fixes

Cutting conditions

• Change the rotation speed to move out of the resonance rangeAgreed by 2+ makers^[5][6][4][8]
• Reduce the depth of cutAgreed by 2+ makers^{[2][3][9][5][6]}
• If the feed is too small, increase the feed per toothAgreed by 2+ makers^[2][5][6][4]
• Reduce the cutting speedAgreed by 2+ makers^{[5][6][9][10]}
• For end mill finishing, try up millingAgreed by 2+ makers^[2][4]

Tool

• Use a tool with fewer teeth, or an unequal pitch or unequal lead toolAgreed by 2+ makers^{[2][8][7][5][12]}
• In turning, reduce thrust force by using a smaller corner radius and a 90° lead angle (smaller side cutting edge angle)Agreed by 2+ makers^[1][3]
• Use a sharp positive geometry with small honingAgreed by 2+ makers^{[1][2][3][12]}
• Use a larger tool diameter or shank diameter, a carbide tool, or a tool with a large core thicknessAgreed by 2+ makers^[5][8][10]
• Replace the worn cutting edgeOne maker^[1][2]

Setup

• Shorten the tool overhang (use a thicker boring bar and a longer gripping length)Agreed by 2+ makers^{[1][2][3][4][8][5][6]}
• Increase workpiece clamping rigidity and add supportAgreed by 2+ makers^{[2][3][7][8][5]}
• Check runout, and replace or retighten the chuck or colletAgreed by 2+ makers^[2][4][5]
• Use a holder with high gripping rigidity, such as a shrink-fit holderOne maker^[5][6]
• For long internal bores, use an anti-vibration bar or a carbide barOne maker^[1]

▦Notes by material

• Titanium alloy: Young's modulus is about half that of steel, so it deflects easily, and chatter and loss of accuracy tend to occur on thin parts^[13]

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