Causes and countermeasures of machining vibration problems

In CNC milling, vibration may occur due to the limitations of cutting tools, tool holders, machine tools, workpieces or fixtures, which will have a certain adverse effect on machining accuracy, surface quality and machining efficiency. To reduce cutting vibration, relevant factors need to be considered. The following is a comprehensive summary for your reference .

Fixture with poor rigidity:

• Assess the direction of cutting forces and provide adequate support or improve fixtures.

• Reduce cutting forces by reducing the depth of cut ap.

• A milling cutter with coarse pitch and uneven pitch for sharper cutting edges.

• A geometry with a small nose radius and small parallel lands.

• Choose fine-grained uncoated blades or thinly coated blades.

• Avoid machining where the workpiece is not adequately supported to resist cutting forces.

Workpieces with poor axial rigidity :

• Consider using a shoulder milling cutter with a positive geometry (90° entering angle)

• Select an insert with an L-groove.

• Reduced axial cutting forces - smaller cutting depth, smaller nose radius and parallel margin.

• Choose a sparse-pitch milling cutter with uneven pitch.

• Check tool wear.

• Check tool holder runout.

• Improved tool clamping.

Unstable table feed :

• Tighten the machine feed mechanism: For CNC machine tools, adjust the feed screw.

• For conventional machine tools, adjust the locking screw or replace the ball screw.

Cutting data :

• Reduce cutting speed ( vc )

• Increase feed (fz)

• Change cutting depth ap.