Why is the 1000th layer shifted

[LeoZumi 0]

I have a Tevo Tornado and I recently started to print some big things (more than 100 layer) and with every of these there is a layer wich shift all the next ones by few millimeters.

Wich is very annoying when you want to print some precise things.

I tried to print the object with a new created g.code and nothing changed. I tried to creat another profil but nothing changed.

I don't see anything else to try.

Thank you for your help

[JohnInOttawa 104]

Not a printer I am familiar with, however if the problem is always at exactly the same height, regardless of how long it took to get there (i.e. narrow, low infill jobs get the same problem at the same height as large, high infill ones), then I would look at a mechanical problem instead of Gcode.

 

Mechanical problems are not all broken things, it can be as simple as dirt in the Z axis leadscrew that causes more friction and missed steps.  This is pretty common, especially in printers where the bulk of jobs stop at about the same spot, so debris gets pushed to the same level and congeals with the lubricant.  Since you indicate that this all started when you recently decided to print bigger things, I'd start there, remember that most leadscrews are multi-threaded, so you may have three groove lines to inspect and clean per leadscrew.

 

John

 

Edited September 27, 2018 by JohnInOttawa

[gr5 2,173]

I don't know your printer but if it was an Ultimaker I'd say one of the belt pulleys are loose.  Each axis has 6 (six!  not 4) pulleys.  Usually the ones that need tightening are the two on the short belts.  In fact it's usually the one on the stepper which is the hardest to get to.

[LeoZumi 0]

I  forgot to say that it's a shift in the Y axe JohnInOttawa so the Z axe can't be guilty for that problem

[JohnInOttawa 104]

Let's try this approach:

 

1) please identify which slicer you are using - if it's Cura, then you're in the right place.  If it's not, and this is not an Ultimaker printer (looks like the Tevo is a prusa style) then you might be frustrated at suggestions here that don't make sense for you.

2) I would try a different file of the same height but using less material so you can get past the shift point sooner - a vertical bar 2.5cm x 2.5 cm or whatever would be stable - just to see if this issue tracks with height, or time.  If you get the same issue at the same height, again, I would think mechanical aspect.

3) Assuming you use Cura for a moment, I would sink the model in Cura to 25 or so layers below the problem area and print just that part of the model, to see if the shift occurs at the same place in the model regardless of how many layers have been printed to that point.  If the shift happens anyway. then you can start to zero in on other things and you won't have to wait so long to see the problem and test a potential solution.

 

I did for a time have a prusa style printer, which also experienced layer shifting at a specific height.  In that case, it was indeed dirt on one of the Z screws that caused an asymmetry in the gantry, when I put a bubble level on the table it was level but the gantry no longer was.  Not saying it's your case, but when things like this take place, it's among the easiest things to fix.

 

John