Stepper motors clicking while printing

Hi all -

I am working on getting my first printer together. Its a delta-pi using RUMBA electronics and marlin firmware. I have everything together and it seems to auto home correctly. The steppers run smooth when going to home but when I tried to do an "air" print the steppers click a lot and have really jerky movement. I used repetier and slic3r to make the g-code and I think I have all the settings correct for my delta. Also, after each test I need to re-tension the belts because they pull through. They only need re-tensioned when it is clicking.

Any suggestions?

Clicking: [dl.dropboxusercontent.com]

Not clicking: [dl.dropboxusercontent.com]

Have you checked the tightness of the set screws on the belt drive gears?

I have them as tight as I think they can go. I think the clicking noise is the belt teeth moving against themselves. The ends of the belt are pinched together, that is what keeps them in place. It would also be why they are loosing tension. I don't thing its binding anywhere either, it moves freely by hand.

Could be a few things, I would guess the stepper drivers are overheating. They go into a thermal shutdown then restart, which happens quite fast, i.e. several times a second, so you get a very jerky motion. Either dial back the current limit or get a fan on them.

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So I added heat syncs and fans and dialed back the drivers. That solved it, super smooth. Now if the pla and Bowden tube I ordered would show up...