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Causes and Countermeasures of CNC 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 certain adverse effects on machining accuracy, surface quality, and machining efficiency. To reduce cutting vibration, related factors need to be considered. The following is a comprehensive summary for your reference.(ALUMINUMMOD CASE)

    Poorly rigid fixtures

    1) Evaluate the direction of the cutting force, provide adequate support or improve the fixture.
    2) Reduce the cutting force by reducing the depth of cut ap.
    3) Choose sparse and unequal pitch milling cutters with sharper cutting edges.
    4) Select a geometry with a small nose radius and a small parallel land.
    5) Choose fine grain uncoated blade or thin coated blade.
    6) Avoid machining when the workpiece is not supported enough to resist the cutting force.

    Workpieces with poor axial rigidity

    1) Consider using a shoulder cutter with a positive rake geometry (90° entering angle).
    2) Choose inserts with L geometry.
    3) Reduced axial cutting forces – smaller depth of cut, smaller nose radius and parallel land.
    4) Select unequal pitch sparse milling cutter.
    5) Check tool wear.
    6) Check the runout of the tool holder.
    7) Improve tool clamping.

    Tool overhang is too long

    1) Minimize overhang.
    2) Use unequal pitch sparse milling cutter.
    3) Balance radial and axial cutting forces – 45° entering angle, large nose radius or round insert milling cutter.
    4) Increase the feed per tooth.
    5) Use light cutting insert geometry.
    6) Reduce the axial depth of cut af.
    7) Up-cut milling is used in finishing.
    8) Use oversize cutters and adaptors with Coromant Capto® interface.
    9) For solid carbide end mills and interchangeable head mills, try a cutter with fewer teeth and/or a larger helix angle.

    Milling square shoulders with a poorly rigid spindle

    1) Choose the smallest possible diameter milling cutter.
    2) Choose light-cutting cutters and inserts with sharp cutting edges.
    3) Try up milling.
    4) Check the spindle deflection to see if it is within the acceptable range of the machine tool.(THUMB KNOB)

    Unstable table feed

    1) Try up milling.
    2) Fasten the machine tool feed mechanism: For CNC machine tools, adjust the feed screw.
    3) For conventional machines, adjust the locking screw or replace the ball screw.

    cutting parameters

    1) Reduce the cutting speed (vc).
    2) Increase the feed (fz).
    3) Change the depth of cut ap.

    poor stability

    1) Shorten the overhang
    2) Improve stability

    Vibration in corners

    1) Use large programmed fillets at lower feed rates

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