Breaking Z belt help

After several (10-ish) successful carves on the X Carve, the Z axis GT2 belt snapped. I replaced it and about an hour into the very first carve, it snapped again. Thankfully I bought multiples. I am still new at this, so would any kind soul direct me to some possible solutions? I am assuming that it is alignment related, but am not 100% sure how to check.

Another probably-related issue is that when running the homing cycle, the Z axis sometimes makes a grinding noise when near the top and needs a little push to get it all the way.

Apologies if this is a foolish question. Thanks for the help!

Thanks very much. I will try loosening them a bit and see if that helps.

Check the v-wheels too. You should be able to just barely turn them by hand against the v-rail. If they are too tight it could increase the torque needed to move.

I’ve had the two bolts that hold the delrin nut back out a little causing slop in the z-axis. I tightened them lightly with a very tiny dab of super glue on the underside of the head. It’s enough to keep the screw from backing out, but not enough to keep you from removing it easily.

One of two things (probably).
Pulley alignment in the horizontal plane. Causes the belt to rub on the lip and wear/break.
Or you are tightening the motor too far back. (I doubt it’s that since I did that all the time and I only broke the belt on purpose once to see where it would happen.

A lot of very helpful suggestions here. Thanks everyone. I’m hoping to get out in my shop today after work and will try the things you suggest. I do have the belt really tight, thinking that that would help increase the grip of the belt’s teeth on the pulley. I’ll update with a solution ASAP.

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Tightness is not really the issue except when it will cause snapping or binding plus it’s turning a screw so no need for super tightness.

So it seems like I had 2 problems. The Z belt was very tight, not able to slip at all and the top 2 v-wheels on the carriage were very tight, so I loosened them up to allow them to be turned by hand. So far, so good. Thanks again, all!

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Nice! I think I may just use that idea. Mind sharing where you found those parts?