When to replace belts?

Hi all!

Some quick questions about the belts: How long will they last? How often should they be replaced? What signs, if any, are there to tell of fatigue and impending failure? What would happen if they break during printing, will it break other parts of the printer?

I’ve been printing quite much recently, and while I like to think I know how to spot other parts that may need semi-regular replacement with a 24/7-printing schedule (I’d say the nozzle along with the isolator (mostly because it becomes brittle with extensive temperature changes and breaks easily while exchanging nozzles), the buildtak surface, the radial fan and the end caps), I can’t help to think the belts should go next, but I have currently no way of telling. Please help! Many thanks in advance!

Personally i didn’t had to change the belt.
I’ve got the vertex since release and print very regularly and i didn’t need to replace them.

Just in case, i’ve bougth one of each. It is better to have them here than to wait for delivery…

Yeah, I’m thinking like you @Zorro_X, but I would buy two of each. If either belt fails, especially during a print, the other one will surely fail very soon after, if not at the same time. But also, there’s the issue of belts being a perishable…

@VEL337, that sounds nice and may not be an impending issue for me after all, but I don’t believe any belt will last forever. There are signs of small filings, debris or particles from the belts accumulating on top of the motors, so soon enough, enough material from the belts will flake off. By comparison, my first (used) car had about 150 000 km in it before the cam belt gave up. Have you “simulated” what happens if one belt gives way? Will something smash up or get bent? Is it safe to drive into the wall, so to speak?

The belts on my K8200 have to work a lot harder (much heavier print bed) and after a few years, they are still like new. They may not literally last forever, but then nothing will. If one breaks, depending on which one, either one axis will stop moving completely, or one axis will begin to skew. Neither should be catastrophic at all.

As for your car analogy; lets do some math. Lets assume you achieved an average speed of 60 Kmh, that means the engine ran for ~2500 hours. Lets also assume on average, it revved around 2500 rpm and the belt is 2 meter long. It thus travelled a total of 2500 rpm x 60 min/hour x 2500 hours x2m = 750 000 000 meter. Of course, its more sturdy than the timing belt on your printer, but that should give some perspective. These things are tough.