Solved Printer stops increasing in Z

With more complicated prints, my Robo reaches a certain height (usually about 7mm off the build plate) and stops increasing the z step. The print continues in X and Y, but the Z fails to increase. The printer will lift the Z axis as it normally does during printing in order to start a new pass or whatever, but ultimately won't increase the Z layer height. Has anyone else had this issue? I am using a RepRap LCD controller with g code generated from Repetier Host through Slic3r. I have tried simple prints like a basic hollow cylinder and have no issues whatsoever.

 

I tried the same part with MatterControl and MatterSlice and have gotten the same issue.

 

Sounds to me like your Z stepper motor might be overheating. Try printing lifter feet and ensure the fan is blowing on the ramps board underneath.

 

Good call MIke! Thanks for the tip. I printed some lifters and now it seems to be working totally fine.