Offset during print resulting in a birds nest

[Marneus68 1]

Hello,

I started a print yesterday and let it run overnight. It all started great, but when I came back to work this morning I was greeted by the following mess:

The print is relatively large and takes almost all the space on the print bed. It had to manually level said bed in order to make the brims and first layer stick better to the base. It seems to me that the nozzle may have been stuck in some places resulting in some sort of offset on the upper layer, thus resulting in the birds nest you can see up there. Here are the details that make me think this might have happened, however I wasn't there to see the printing process:

Any idea of what might have happened as well as tips or suggestions as to how to avoid it?

[gr5 2,167]

Is the offset only in X? or only in Y? I can't tell. But those offset squares could be caused by whatever they are sitting on moving. or it could be a slip in X or Y. I would tighten the pulleys as this is a very common problem and so easy to fix. Figure out which axis is slipping and only tighten those pulleys. You need a 2mm hex and you need to tighten the hell out of those set screws - enough to twist the metal Enough to cause pain in your fingers. With bare fingers and L shape go as hard as you can without injuring yourself.

You have to get the pulleys on the long belts but more importantly the 2 pulleys connected to the short belts which means the pulley at the motor. That is the hardest to get to but also the most likely problem. You might even have to remove the stepper briefly to get to that pulley. I have not done this yet on my UM3 (only UM2 and UMO). On UM2 you sometimes have to remove the corner cover (2 screws hold it in place) and then the stepper is exposed. Then you can possibly tighten the pulley at that point or remove the 4 screws holding the motor in place and tighten pulley set screw and put the motor back in place pushing down on the motor to keep that short belt tight when you tighten the 4 screws the final turns.

[geert_2 557]

Question: if you tighten the screws "as hard as you can", then don't you destroy them? Or the hex tool? These small M3-things don't look very strong...

[gr5 2,167]

If you are using pliers or large handeled hex drivers then yes you can damage things. But if you are using an "L" shaped hex wrench and if you push the wrench all the way in then, "No, you can't hurt it".

Not unless your fingers are strong enough that can hang from a ledge by just the last part of your finger tips.

I was also afraid I would break something but I have 5 printers and have done this maybe 100 times. As long as you use just your fingers and an L wrench you will be fine.

This tool can break things:

Edited January 12, 2017 by Guest