What causes "chatter" in your CNC router?

It shows up when you inspect your CNC router (you do have a regularly scheduled maintenance routine, don’t you?). It’s not welcome; and it’s hard to find the real cause of it.

It gets loud and obnoxious. It ruins your work quality and, it’s just not wise to let it persist once you’re aware of it.

What is it?

Chatter. That unwelcome vibration that reduces the quality of your work.

What causes it? What do you do about it?

Here are our thoughts:

1. First, Check How Much You’re Routing

If you’re routing a large part, that can certainly lead to the chatter you’re experiencing. In fact, it’s often the primary cause.

Slow your router down, take less off, and do more passes. It’s the best place to start first. If that doesn’t remove your chatter, then move on to check number two:

2. Loose Bearings

Yep, sometimes your bearings will rattle loose. Check them all and tighten as needed. If applicable replace them all together.

3. Try Adjusting Your Feeds and Speeds

Remember, the faster you cut, the higher your surface finish ends up. There’s a tradeoff. You’re going to have to figure out what works best for you and your customer’s interests.

Double-check you’re using the appropriate feed and speed rates for the material you’re cutting. You don’t always have to slow down. Sometimes, speeding up actually reduces chatter.

4. How Do You Hold Down Your Work Material?

A common rookie mistake is to hold down your work material incorrectly while you attempt to cut. Justification pins, horizontal cams, vacuum pods, and t-rack systems can be used to help you secure your material.

Finally, how you hold down your work piece depends on the type of CNC router and what you need to work on. You may have to test various methods before you find the one that works for a majority of your cutting.

5. Other Odds’N’Ends to Check

Your whole CNC router may be vibrating, leading to the chatter you have. It could be that you left your leveling screws loose, or maybe you did the same with other components on your CNC router.

Check your router’s belts too since they need to have the right tension. They may also have other defects, like missing chunks that can lead to chatter.

If you’ve checked off on this whole list you should be able to find the reason for your chatter. Once you’ve eliminated the chatter, you’ll be able to get back on track to making high-quality cuts.