My CNC's new belts are causing intense vibrations

I put in fresh drive belts last shift. Now, during heavy cuts, the machine shakes so much the parts are coming out rough. Any tips to fix this?

4 comments

4 Comments

lee_thompson1mo ago

Hey there, I had that exact problem on my Bridgeport after a belt change. In my case, the tension was way too high on the new belts. I loosened them just a bit until they had a little flex, and the vibrations stopped completely. Also, give the pulley alignment a good look with a straight edge.

aaron8541mo ago

Seriously, Lee is spot on about the tension. An overtightened belt doesn't just pull hard, it actually starts to sing or vibrate at a certain pitch when the spindle spins up. You want just enough tension so it doesn't slip under a normal cut. I'd add that you should check the tension at a few spots around the pulley, sometimes it feels even but isn't. Oliver mentioned it too, it's a super common mistake to crank them down like a head bolt. Just go easy, a quarter turn can make a huge difference, and for sure don't go past the point where the shaking stops or you'll get slip instead.

oliver_nguyen151mo ago

Yo, I heard about this exact thing on a forum last week. @lee_thompson has the right idea, definitely check if you cranked the tension too tight.

ivan7741mo ago

Wow, I botched a belt job once and the shaking scared my cat, did you align the pulleys?