Welcome to the SeeMeCNC Community

Has anyone else experienced this kind of failure? The print is going fine, then I leave it alone for 5 minutes and when I get back it appears that the nozzle has translated its understanding of where [0,0,0] is... and hence ends up printing off to one side, mid air, or in the worst case, crashing into the bed.

[img]http://s28.postimg.org/w0h5lj9st/DSC_0004.jpg[/img]

I am getting this kind of thing happening once in a while, ie it is not repeatable if I run the same g-code multiple times.

Sorry if this has been covered somewhere else, but I struggle to find the right keywords to describe what's going on.

Cheers

It is probably hitting the part hard enough for either a belt or a motor itself to skip, and from the point where anything skips on a delta, things are going to go wild. If that's what's going on, the keys will be keeping the warp/curl to a minimum, taming any overextrusion you might have, and finding settings that prevent blobbing on retraction.

There is no position feedback, the head is just commanded to move and it's assumed to succeed. If the head hits the part, or a belt is damaged, or a stepper gear loose, or some other mechanical issue, then it will start printing at the wrong place.
Check the pulleys and belts, but watching the print fail is usually the only way to diagnose what's happening.

Thanks for the thoughts there - I ended up tightening the belts (they were a bit slacker than I had thought them to be) and that seems to have solved it.

And yes that part was curling up a bit, really should thicken up that section a bit to reduce that.