Giving up on my dragon as it won’t print on my @Ultimaker 2 There is a bug in Cura that generates a XY-displacement if using a raft/brim on some models (see just below the stomach) and printing the dragon without brim makes many of the supports come loose during printing. With brim they seem to be stuck nicely to the printbed. 
@Daid_Braam , any ideas on how I could work around the XY-displacement issue?
Ps. Here is the dragon model: A Better Dragon by illuminarti - Thingiverse
#3dprinting
Can you not just use a different slicer to create the gcode, or is Ulitmaker proprietary?
Does the XY displacement show in the layerview?
Not that I know much about 3d printing, but it sticks (pun intended) in my mind that people spray the print bed with hairspray to make it easier to remove prints. Also, a guy on youtube sprayed his print with compressed air (I think) to quick-cool it, and it popped off the bed nicely. Haven’t tried these, but thought I’d pass them on. 
@Daid_Braam nope. I tried reslicing as well but no difference.
Expensive fix but, you could try a raft instead and see if that doesn’t have the same bug?
@Peter_Parnes then it would not be a bug in the slicer, but electrical/mechanical step loss. I’m actually surprised to see the Ultimaker suffering from this.
Ok, a couple thoughts. 1. Does the offset show up in your slice preview? If I doesn’t, make sure there isn’t a pinch in the x/y motor wiring. It is possible that a small short is causing that little jump. 2. If that’s not the case have you tried moving/turning the model to a different position on the bed and slicing again? I found with all the printers I’ve used that sometimes the position on the bed can cause issues with either the slice or the actual physical movement causing bad prints. Simply spinning or moving the object usually fixes it. 3. On the whole brim and raft thing I thought these were just different word for the same thing??
Oh no! What a shame! As a plus, I reckon that middle one would make a fabulous pencil holder for your desk.
Also if the x/y is the result of a cura bug maybe add some small 1 mm high disks under each support and the model yourself in your 3d editor of choice and print with no brim. Look up helper disks on thingiverse. Essentially create your own brim as part of the model instead of letting cura create it.
Have you tried a 10:1 water/PVA glaze on the bed. Paint it on, heat up bed to dry it. We found it better than hairspray. More difficult to get off bed though, try sharp tap to side with something.
@Thomas_Sanladerer i thought it was a slip the first time but on the second print I got the slip on the exact same layer. Thus cannot be a slip, or?
@Peter_Parnes were you watching the print when it failed?
I’ve had a similar problem on a print where gcode would look perfect, but it would skip on almost the same spot each time. As it turned out, my y-axis was going into resonance and consequently missed a couple of steps.
Now, the Ultimaker has far lighter axis than my machine, but prints faster and uses thinner belts, so it’s entirely possible it’s the same problem.
If you know where it skipped, use a gcode viewer and look for small, consecutive moves, like infill on a thin area.
Sometimes, just slightly altering the nozzle diameter in the slicer can get rid of the skips (but introduces them in other prints). The only real solution, though, is lowering the axis’ acceleration.
No I was not watching it and you might be right. Note though that without the brim it did not skip. Will do another test.
You can set a new maximum acceleration via gcode, using M201:
// M201 - Set max acceleration in units/s^2 for print moves (M201 X1000 Y1000)
The command will last until the next time you shut the printer off.
@Daid_Braam set 5000mm/s² as the default for the Ultimaker 2, so try sending M201 X2000 Y2000 before or during the print and see if that helps.
Slic3r seems to get blamed for similar behavior as well:
https://github.com/ErikZalm/Marlin/issues/305
Had similar symptoms from a Y stepper driver over heating. Almost exactly the same spot every time but changed with infill pattern. Only on large objects with many fast non-extruding moves, such as between your support pillars.
@Thomas_Sanladerer Actually, the acceleration has been set back to 3000 on new machines.
@Daid_Braam i took that value from https://github.com/Ultimaker/Ultimaker2Marlin/blob/master/Marlin/Configuration.h - are those files not up to date?
Odd, pretty sure I changed that
if the problem is the slicer then try kisslicer or sli3r and see if it goes away. If you are using repitier host you should be able to see the error in the g-code. If you don’t see an error in the g-code and/or a different slicer doesn’t work then chances are it’s mechanical. Thats a long print so I would check the current settings for your steppers and check if they are getting hot. Another option is to split the print in to two parts and then glue them together.
