Apr 18, 2023 Leave a message

Causes And Countermeasures Of CNC Machining Vibration Problems

 

In CNC milling, vibration may be generated 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.

Fixtures with poor rigidity:
1) Assess the direction of the cutting force, provide adequate support or improve the fixture
2) Reduce cutting force by reducing depth of cut ap
3) Select coarse and unequal pitch milling cutters with sharper cutting edges
4) Choose a geometry with a small nose radius and a small parallel margin
5) Choose between fine grain uncoated blades or thinly coated blades
6) Avoid machining when the workpiece is not supported enough to resist cutting forces

Workpieces with poor axial rigidity
1) Consider using a square shoulder milling cutter with a positive geometry (90° entering angle)
2) Choose an insert with an L-groove
3) Reduced axial cutting force - smaller depth of cut, smaller nose radius and parallel margins
4) Choose unequal tooth pitch coarse tooth milling cutter
5) Check tool wear
6) Check the runout of the handle
7) Improve the tool clamping situation

Tool overhang too long
1) Minimize the overhang
2) Use unequal pitch coarse-tooth milling cutter
3) Balanced 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 milling is used in finishing
8) Using oversized milling cutters and adapters with Coromant Capto® interfaces
9) For solid carbide end mills and replaceable head mills, try a cutter with fewer teeth and/or a higher helix angle

Milling square shoulders with a less rigid spindle
1) Choose a milling cutter with the smallest diameter possible
2) Choose light-cutting milling cutters and inserts with sharp cutting edges
3) Try up milling
4) Check the amount of spindle deformation to see if it is within the acceptable range of the machine tool

Unstable Table Feed
1) Try up milling
2) Fasten the feed mechanism of the machine tool: For CNC machine tools, adjust the feed screw
3) For traditional machine tools, adjust the locking screw or replace the ball screw

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

poor stability
1) shorten the overhang
2) Improve stability

vibrate in corners
1) Large programmed fillets at lower feedrates

 

 

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