Why Is My CNC Machine Vibrating? Let's Sort It Out

These feel similar but they're not the same, and the fix is different. 

Vibration is a low-frequency shake through the frame — you'll feel it underfoot. Chatter is faster and leaves wave patterns on your finished surface. 

Both are fixable. But you need to know which one you're dealing with. 

 

We see these every week across the UK: 

• Worn spindle bearings — gets worse at higher RPM, often with a low rumble. Classic sign the bearings are on their way out. 

• Tooling out of balance — a tool not running true wobbles at speed. Your surface finish knows before your ears do. 

• Loose workholding — aluminium or PVC not properly clamped will flex against the cutter. Check the clamps before you blame the machine. 

• Ball screw wear — tiny play in the axis drive shows up as vibration during cutting moves. Easy to miss, gets worse fast. 

• Machine not level — seriously, check the feet. A rocking machine sends vibration everywhere. 

• Feeds and speeds too aggressive — pushing aluminium too hard drives it into resonance. Back the feed rate off and see if it stops. 

 

Run the spindle at different speeds with no tool loaded and just listen. 

Noise peaks at a certain RPM? That's resonance or bearing wear. Consistent at all speeds? More likely mechanical looseness. 

Then do a quick walk-around — loose guards, swarf in the wrong place, anything visually off. Nine times out of ten, the answer's staring you in the face. 

 

Workholding fine. Tooling fine. Machine level. Still vibrating? 

Stop guessing. Spindle bearings and ball screws aren't things to get wrong twice. We deal with exactly this every week — machining centres, autosaws, bandsaws — all across the UK.