Printer problem

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Gordon

Gordon

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Recently I began having a problem with my "Y" axis slipping during printing. I have an ANET A8 printer and I am using Cura 5.6.0 slicer. I recently changed to a newer computer and the problem seems to have started about that time. The old computer was using Cura 5.3.0 and I found a discussion on line where someone went to the earlier software to fix a similar problem. I am not sure if that will fix it but it seems unlikely since I do not find any others having that problem. I have tightened the cog belt on that axis and I have cleaned the guide rods with alcohol. The bed is supported on guide rods with linear ball bearings. I also put on a new glass bed but I was using a glass bed prior to that but the new bed is 4mm and the old bed was 3mm so it is marginally heavier.

I am open to suggestions. I have 6 or 8 pieces where the printer slipped and there is about a mm offset, sometimes 2 or 3 offsets if I don't notice it and shut it down.
 
I don't have that printer so this might be way off the wall. I changed my mini-mill to CNC and found that sometimes it would skip a step. As far as I could tell, the driver chip was overheating and shutting down for a fraction of a second. My solution was to increase the voltage and decrease the maximum current but in your printer I don't think you can do that. The other thought is to decrease the Y acceleration as that might be overwhelming the driver chip for the motor. Cura has so many settings it might take you a while to find that setting. The other thought would be the maximum speed.
 
I am thinking slowing down the Y acceleration also. I have an A8, and when I put the new Cura on my linux machine, I noticed that the printer had a different personality, a lot quicker and jerkier feeling than when I use the version of Cura that came with the machine. I have not had shifting issues like you are describing and have not tried to compare settings.
 
I went to the old computer and duplicated all of the settings from the old computer without going to the older Cura version on the new computer. I also found the settings for acceleration on the menu on the printer. I was looking at the Cura settings on the computer and could not find a setting for acceleration. I set the machine acceleration from 400 to 300 and printed a part. It seemed to be correct without shifting. I will try a more complex part tomorrow and see how that works. If that works I will probably try setting acceleration to 350 to see how that works.
 
Gordon said:
I also found the settings for acceleration on the menu on the printer. I was looking at the Cura settings on the computer and could not find a setting for acceleration.
Click to expand...
In Cura, make sure all the settings are visible via:

Settings/Configure Setting Visibility
 
Usually the acceleration is specified in the firmware of the printer, not in the slicer software.
Probably threre is no setting for the acceleration in Cura.
But, ... often the normal movements stay below the maximum acceleration. On my printer when there was one "bad move" were it wanted to speed up fast. It started skipping steps on those single "bad moves".

e.g. if there is a (long) repositioning move in y-axis it skips steps. If the part is rotated in the cura software the fast move is divided into a combination of Y-and X- and suddenly it works, because x and y motor work together and both a little slower.
So the change can be caused by settings in the infill pattern or general speed, part orientation on the build plate, things like that.

Problem on my printer was; the driver is at its limit and was overheating. A cooler made things better, but this fixes the symptom not the root cause.
On the small CNC mill a few drivers suddenly quit service. (wild guessing here: if the drivers run on the edge of their specification for a while they degrade over time and finally stop working ) A lot of "designers" seem to mix up the "absolute maximum ratings" with "typical application", it is ignorance or fraud. (probably a mixture)
Cura.jpg


I would experiment with those speed settings specially I would have the infill (in combination with the infill pattern) under suspicion :)

Good luck, layershifting sucks!
 
Last edited:
timo_gross said:
Usually the acceleration is specified in the firmware of the printer, not in the slicer software.
Probably threre is no setting for the acceleration in Cura.
But, ... often the normal movements stay below the maximum acceleration. On my printer when there was one "bad move" were it wanted to speed up fast. It started skipping steps on those single "bad moves".
Click to expand...

LOL, open your eyes! In very snapshot your posted, what does it say at the bottom? o_O

Yes, Cura can't set the acceleration faster than the top limit in the firmware (Marlin), but you can certainly set it lower. It's pretty much the default setting of every printer to use lower acc/speed settings for the first layer and that's done via the slicer.

You are confusing speed and acceleration. The print head will always accelerate at the specific setting, but often can't hit the top speed unless it's a long, straight line. You can view line speeds graphically in Cura.
 
I am not experienced enough to determine what is causing the problem but I set acceleration from 400 to 300 and reprinted a part which had shifted and it printed with no shifting. I am presently printing the mating piece which is 40% done and it has not shifted. In the previous attempt it has shifted three times by that point. If setting the acceleration fixes the problem I do not care if it increases my print time by 10 minutes. That is much better than producing scrap.

Thanks to all of you for your input.
 
Greetings,

When you check enable acceleration control in Cura all the acceleration settings will be displayed. You may need to click hte hamburger (three horizontal lines) to the right of the search settings box and select expert, I rarely use Cura.

In all seriousness though, you might try PrusaSlicer or Orca slicers, both have a lot of features and utility not found in Cura. Changing will take a bit of time to find things, and a few google searches to find how to do things. There are some differences from Cura, but they make so many things easier. The ability to cut up a model that has no flat surfaces so you can place the cut flat face on the build plate (then glue the parts together) or to cut a model so the parts fit your printer are very useful. I very rarely fire up Cura unless I get some model that is just oddly saved from Cura and doesn't want to play nicely in other slicers. This is a VERY rare event, maybe once or twice in the last year.

Cheers,
Stan
 
krypto said:
LOL, open your eyes! In very snapshot your posted, what does it say at the bottom? o_O

Yes, Cura can't set the acceleration faster than the top limit in the firmware (Marlin), but you can certainly set it lower. It's pretty much the default setting of every printer to use lower acc/speed settings for the first layer and that's done via the slicer.

You are confusing speed and acceleration. The print head will always accelerate at the specific setting, but often can't hit the top speed unless it's a long, straight line. You can view line speeds graphically in Cura.
Click to expand...
You got me there. Haha! Did not see this parameter nor was I aware it exists. But this is obviously disabled :) on my Cura. (which I updated today coming from 5.1 ) I was not aware of the mixture of machine parameters and process data.
Obviously some printers are having fairly aggressive accelerations and run at the limits of their hardware. (otherwise the layer shift would be a "non-issue")

No I am not confusing acceleration and speed, but I might be a little misjudging it. My imagination how the motion controller works might as well be wrong.
I was assuming that the acceleration is depending on the motion controller.

Anyway (accelleration and or step frequency too high) will not work when the system cannot deliver the required torque.
 
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If changing the Accel corrects the problem them might want to look into adjusting the current limit on that axis driver (a small potentiometer on the board) or updating the firmware in your machine. It is not difficult, involves setting up the correct software for your machine - Arduino or Visual Studio Code - and recompiling and reloading with the new numbers. And you might want to look into a 32 bit control board as that does make some things just work better because of higher processing power. I upgraded my delta from an Arduino board to a Creality 32 bit board and the quality improved and the printer got a lot quieter.
 
While back on my now defunct CR10S PRO V2 I had a y axis lost steps problem. I was already printing with a heavier bed due to using a 6mm ally toolplate with mains bed heater and magnet, but it handled that weight ok until a year later. It only skipped when I was printing at high bed temperatures, like ABS or ASA. The first 45 minutes to an hour would be fine, then it started skipping steps. I tried extra cooling on the driver but did nothing.
Due to the temperature related fail I was thinking it had to do with a breakage on the print board somewhere. When hot it would start skipping or loosing connections. I still don't know to this day what really caused it and a while back I blew the mainboard up accidentally by shorting the 24 volt fan output. Since then I have a new printer so I will never really know.
What I have been thinking was also that due to heat distortion the rails that were fixed to my machine casing could get out of line causing extra friction. On the CR10 the base is a sheet metal case which potentially can warp under high temperature. Don't know the construction of your machine but maybe worth looking at too.
Very frustrating problem it was, I hope you will sort it.
 
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