Extruder keeps digging into tall part and knocking it off the bed towards the end of the print!  

Extruder keeps digging into tall part and knocking it off the bed towards the end of the print!

Hi all 😀

My first post on here and new to 3D printing, looks like a great community!

My Prusa MK2 is printing very well at a really high accuracy on my self-build kit. However, on taller prints it keeps randomly knocking the print off the bed at any point once it gets over 150mm tall. The extruder nozzle will randomly dig into the part and literally pull the print off, almost as if the x axis suddenly drops slightly during the layer! The part is perfect up until this point with no signs of the part moving before the event happens.

I have embedded some photographs to show the damage to the part just before it gets pulled off the bed by the nozzle. This has happened at X axis 155mm, 158mm and 175mm now. I am using Simplify 3D as a slicer.

I am trying to get me head around what is going on here and would appreciate any thoughts/help on the problem.

Thank you!