# Z related problems

## My print seems to have *blobs* on corners
![Calibration cube with corner blobs](../img/z/calibration-cube-corner-blobs.jpg "Calibration cube with blobs")

This can occurs for multiple reasons, if no matter what you change on your printer this keeps happening check your slicer.

For instance in Cura I have :

![Calibration cube with corner blobs Cura preview](../img/z/calibration-cube-corner-blobs-cura-preview.jpg "Calibration cube with blobs Cura preview")

You can see for consecutive layers the starting points are aligned. This can cause an amount of material to accumulate and create the blobs.

*Retraction settings might help to prevent the leaking and reduce the quantity of material accumulating.*

Another way to prevent this corner to be the starting point for too long **in Cura** is to change the *Z Seam Alignment* in the *Walls* parameters :
![Z seam setting in Cura](../img/z/cura-z-seam-setting.jpg "Z seam setting in Cura")
Changing to :
![Cube preview with Z Seam Randomised](../img/z/calibration-cube-corner-random-starting-points-cura-preview.jpg "Cube preview with Z Seam Randomised")
Once printed (*with a low quality printer*): 
![Printed Cube with smaller blob](../img/z/calibration-cube-smaller-corner-blob.jpg)