Cura causing skipped X and Y steps - identified specifically to Cura slicer

[DevWolf 0]

I've been in rapid prototyping on FDM for almost 7 years now and I've noticed something with Cura that none of the other slicers seen to cause.

Same print, same settings, across different slicers - something seems to be going on within Cura that's causing the X and Y skips, seemingly related to accelleration.

Before I start, I want to note that one of the issues identified was when you use a Sailfish machine with it. The fan code for Marlin is the "disable acceleration" (m127), so before going forward, to rule this out, ice changed it in the gcode to m126 (instead of the m127 T0 that cura tried to use), which enables acceleration in Sailfish. So firmware acceleration is turned on, and I have it turned down inside the firmware to settings that I know to work with my machine across any scenario I throw at it.

The problem seems to affect, speciffically, small circles and gap filling. The steppers jerk violently and rapidly in these areas and it causes skips. No other slicer displays this issue. I can even boost the speed in other slicers and still can't reproduce it. In Cura, I have to turn print down by nearly 50% to get any kind of security in leaving a Cura print by itself while it does it's thing.

Id like to bring this to the attention of the development department for in house testing to see if the problem can be tracked down. This has affected both Cura 1 and 2, through all builds so far. I've done some heavy research into the issue on forums and the like, and I see that even the UM2 machines do this. Now, you might be saying things like "lube the axis, fix that pulley, tighten the belts, driver current, z hop, etc, etc.." let me assure you that I know these issues well, and have learned the hard way over the past 7 years. None of the typical problems seem to cause it. I spent nearly a year now dealing with this nightmare and have yet to find a mechanical electrical issue as the culprate. I'm familiar with calipers on filament for the average, volumetric to temperature balancing, etc... And I can find nothing wrong with the settings I use, which have been changed to a wide range of differences and not solved the issue. I've done the same in slic3r, kiss, makerware, repitere host, and even mPrint from mBot. Cura is the only slicer that Can reproduce this issue.

Can someone please take a look at this?

[cloakfiend 995]

Post some pics about what you are on about, if it is the missed step issue causing ringing and weird patterns this has been noticed. I use a UM2 though and can leave my prints after 2 mins of baby sitting. I print small to medium sizes and don't really have any real issues. This stepper issue is my only one at the mo but that didn't even get changed with the UM3, so just curious to see if its the same thing as you? I've only been doing this for 3 years but am a perfectionist so study my prints very closely.

Edited June 9, 2017 by Guest

[burtoogle 513]

Hi, could you please post a link to a simple model that exhibits the problem you are troubled with. Having the badly behaved gcode for that model would be useful too.

[DevWolf 0]

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Edited December 19, 2019 by DevWolf

[Deneteus 1]

Did you necro bump this post intentionally?

[AbeFM 35]

I've found I've had to bump the acceleration way down on a printer that never had those issues before.... I keep putting it down, and it keeps coming back.

All my skipping has been in Y-axis, and generally turning the speed down helps

 

I'm just digging into it and don't have enough for a coherent post - also I've only been noticing this for a couple months.... I'm more just lurking but if others are seeing it I, too, encourage you to post.