Getting a 'step' in my print

[Daniel Mitchinson]

Hi to everyone - this is my first post in the forum and I'm hoping someone may be able to offer an insight into a problem I'm getting.

Printer: delta printer, Kossel Mini

Electronics: Ramps 1.4

Firmware: Marlin for delta printers

Host computer: iMac with OSX 10.9

Gcode streaming: Pronterface

Slicer: Kisslicer for Mac, last stable release

Attached is an image showing the defect in the print. The first few layers are all inline, there is then a small shift in the layer alignment along the Y axis of the print. The next few layers are then all perfectly lined up until another small shift back to the original alignment happens and the print then continues without any other defect.

It always seems to happen on the larger prints and always seems to be within the first 3mm to 10mm of the build height.

Things I have tried....

Checked for any slop in the delta arms – a fractional amount but this would have more of a randomising element rather then the clearly defined issue I'm getting

Checked the belts are all tensioned correctly

Checked, reset and tightened all the pulleys to make sure there was no slight slip on the D-flat of the stepper spindle

Changes made in the slicing....

Tried running at a lower speed - same problem

Tried running at a higher speed - same problem and there's no difference in the offset

Changed the layer start point from fixed to spread of 180º and this got rid of the problem, but now have lots of small blobs on outside of print

Conclusion...

Seem like this maybe a software issue, but not 100% convinced this is not a hardware problem. I'll try a different slicing programme and see what happens to try and isolate is this is Kisslicer or my build.

Has anyone else experienced this behaviour?

I'd appreciate any feedback!

[A. Elias]

Since there are so many machines out there it's hard to diagnose.  Are your axis movements smooth and easy?  I've seen something similar with a loose belt on my printer, once tightened it when away.  I wonder if your motor is slipping.  If you  have a RAMPS you might have the option to increase the stepper current.  

Adjust your retraction settings and dry out the filament to remove the blobs.  

ADam

[Lawrence LaRocque]

As A. Elias had stated I just had the same problem with my X axis belt.  Got sloppy, so sloppy i am surprised it did not sip a tooth.  I tightened the belt back up and also noticed that on the single frame on my Prusa i3 that the y axis threaded rods had come loose. I tightened them back up and everything seems fine now. I know its the same on a delta machine, but its worth the time and headache to double check all your screws, belts, and rods to make sure they are not loose.