Problem with eliptical printing

[PROMETEJUS 0]

I have had the ender 4 for about two months now, it works ok, but i've encounterd an issue for which I can't seem to find a solution. Whenever I try to print a circular object it gets streched along one of  the printers diagonals and compressed along the other (it becomes eliptical). the difference is not too large obout half a milimeter on a circle with a radious of 2 cm. but its enought to cause me problems.

Solutions i have tried: Ive tightened all the bolts and made shore everything was correctly assembled, Ive tried upgrading the firmvare an did quite a lot of calibration,(the xyz calibration efect only the deformation in the x andy direction, so it dosnt do anything for me).

For the slicer im using cura and iv tried plenty of different setings, but it doesen't seem to help.

Is this an inherent problem for h drive printers, and is just a limitation i have to accept or can it be fixed?

[MartinKenny 1]

Hi.

I'm experiencing a similar problem to "PROMETEJUS" 'Problem with elliptical printing'.  Four times I've had a problem printing circular objects.  The last was a 130mm 20mm high gear wheel which printed perfectly until 15mm high.  At this point the Y axis decided to shift 20mm greater than the previous layer and continued the subsequent layers with the same error when it should have been the same Y axis as the first layer.  Result is a ruined print after 7 hours of printing.

I have checked all the mechanicals that could have caused the error and all was well.  I then tried out the same STL file through a different slicer and got a perfect print. 

I'm using 'CURA 3.6.0' on an 'Ender 3d Pro' running ' Vanilla Marlin 1.1.9'.

If I can find a solution to the problem I would like to continue using 'CURA' as I have got it tuned to my satisfaction in all other aspects.  Any help would be gratefully accepted and it would probably help "PROMETEJUS" too.

Regards

Martin

[gr5 2,173]

We see this a lot.  A LOT!  It's a hardware problem.  Sorry.  I know different slicers pick different speeds (if you give cura one speed it will actually print with several different speeds under the hood).  Cura might just slice it slightly different such that a corner is taken a little faster and sharper than a different slicer.  So it can fail with one slicer and work fine with the other.  Or maybe your other slicers are specifying acceleration (cura shouldn't do that) and they are lowering your acceleration for you.

 

But the top acceleration should be set in the printer firmware.  Not the slicer.

 

No usually this means a pulley slipped.  Tighten the hell out of all set screws that hold the pulleys to the shafts.  The one most likely to slip is usually the one on the stepper itself as that one experiences the most torque.  Concentrate on the slipping axis (Y axis for you).

 

Another fix is to lower the jerk and acceleration settings in your firmware.  But ideally you should fix the hardware.

 

[Rolf Libakken 0]

Hello, I have experienced the same situation, I had to lubricate the drive shafts and everything was fine.

[MartinKenny 1]

1 - nill to GR5 "The Moderator"!

I still think it's a problem with CURA but took the advice and lowered the "Jerk Speed" in CURA from 20 to 10 with no expectation of success and after a ten hour print I have a perfect component for the gear system I'm experimenting with.

Cheers GR5!

Regards

Martin