Shifting layers

Hi guys 'n gals

So i recently bought my first 3d printer, a Delta printer.
First few prints off of it came out pretty good already, had some trouble with stringing but that was quickly fixed.
Now i ran into a new problem with the longer prints... after a while it seems that the layers shift, not the same every time but always in the same direction.

After googling that problem I found a few possible solutions one of which was checking the pulleys on being fixed or not.
Those still seemed to be fixed.

Second possible solution was turning down the pot-meter on the stepper drivers because they'd be getting too hot.
Instead of doing that I thought I'd try cooling them instead with a little fan, but without success.
Well... partially i think, the shift wasn't as big as it used to be but was more frequent.
Instead of one big shift it had 2 smaller ones in roughly the same amount of layers.

Now as I said, I'm a bit hesitant in medling with the pot-meters on the stepper drivers.
Could there be any other causes for my problem?

Hope someone can help me out,
Rick

Got a picture of your shifted layers on your object?

Attachment 7256

That's it, the two different shifts.

I think either your current of your stepper driver is to low, missing steps, or to high, going into thermal protection.check your current settings of your stepper drivers

I'm a bit hesitant to meddle with those settings without knowing how much I have to adjust them.
Is there any way I can measure the outputs and is there a set amount of current needed for the stepper motors?

So is there any way to measure the outputs and are there any settings it should be set around?

I had the same problem with my delta. Some things I did to help eliminate the problem was to make sure the hotend was held in securely. before when it bumped through the wall of it would make it shift as my printer came with a wooden piece that held the hotend in. I bought an aluminum one and that helped. also in the slicer config you allow it to raise up when making a long move. i had an issue of it dragging along the part and causing it to shift as well. it still happens from time to time when slicer allows the nozzle to drag over the part but, it has been for the most part fixed

@Offroadbob, I had that problem aswell, when looking through the slicer settings i found the appropriate settings for the move and made it standard in any of my prints now.

did it fix your problem?

another cause is your part warping or curling a little as well as overextrusion. both can cause the nozzle to hit the print on travel moves knocking it off steps. you generally want a little z-hop or vertical lift on travel moves. another common cause is with the firmware. assuming you are running marlin firmware, when use the arduino ide to compile and upload it then you must use version 1.5.0 or below. there is an issue with the versions above that which cause skipped steps.

Already have the Z-hop/ vertical lift in every model i try and print.
I checked the pulleys on being fixed and they where.
Which takes me to the last possible thing that it could be, the stepper drivers getting too hot.
Which would be fixed by turning down the pot-meter on the boards and putting some forced cooling on them.

But, does anyone know if there's fixed settings for the pot meters?

why don't you put cooling fins on your motors like for a CPU ?

On the motors? I was under the impression the drivers where overheating.

Both overheat easily, motor can go 100C+ easily and on top of that your driver can go nuts in heat too.

Tried the longer print again today after measuring the voltage through the potmeter with a proper multimeter.
They're set to roughly 0,5V now and the extruder stepper to 0,65V with a cooling fan.

Both the stepper drivers and the stepper motors where still cool to the touch.

So any ideas on what to try next?
Any known bugs in Slic3r maybe?

Ill say it again. Its highly probable that its the arduino version you are using to compile the firmware with.

Also your accelleration and or travel move speed is too high

Quote:

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Originally Posted by eXodus

Tried the longer print again today after measuring the voltage through the potmeter with a proper multimeter.
They're set to roughly 0,5V now and the extruder stepper to 0,65V with a cooling fan.

Both the stepper drivers and the stepper motors where still cool to the touch.

So any ideas on what to try next?
Any known bugs in Slic3r maybe?

---

You're right in the appropriate range for voltages. I run .65v for my extruder motor and .5v for my xyz motors.

In my opinion you are not having motor voltage issues. Motor voltage issues usually manifest in single layer skips, then a return to normal, then maybe another single layer skip later. Essentially...occasionally step misses that are fixed on every retract. With that said...do you have retract set up in slic3r?

I've also seen shifts like this manifest from binding in carriages and belts. If you have a bind in your carriage bearings or belts somewhere that could result in what you are seeing.

I'll try and check the version this afternoon, it'll be a first for me.

I've set up my retract to be 4,5mm, which solved a stringing problem I had before.
So I think that amount is adequate.

Quote:

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Originally Posted by jimc

Ill say it again. Its highly probable that its the arduino version you are using to compile the firmware with.

Also your accelleration and or travel move speed is too high

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The software version you mentioned before was it the windows software or the marlin firmware?
Cause I have absolutely no idea, as I'm new to this.

Edit: just found out the firmware the printer is running on is Repetier, does this have the same problem with the arduino?

Haven't got any luck reflashing the arduino Mega, as i don't have the original firmware yet.
Tried it with a modified version of the repetier and marlin software but no luck getting it to work yet...

yes you will need your marlin firmware of course but what i am talking about is the version of arduino itself which you download from the arduino website. you need an older version. i follow some talk with some developers which is way over my head but this has been a long going problem which no one really figured out what the actual cause was until recently. something about the way marlin is written doesnt jive right with the newer arduino versions so when its compiled there is some kind of bug produced that causes skips if your speed and acceleration are too high. if they are really low you wont see the issue. until it get all worked out you need arduino 1.5.6 or earlier. just double checked that version and its correct.

Problem is, so far I've only figured out how to get the repetier firmware to work.
Half that is, some problems with the end stops and stuff.

Haven't got marlin to work with the lid controller yet and have no idea why.

Was uploading marlin with arduino 1.5.0 and repetier 0.91 with arduino 1.0.6.


Edit:
So now got the latest firmware from the reseller, seems to be repetier 0.91 version so have to use arduino 1.0.6 for that.
Uploaded and working for a bit, now when I tell the printer to go to the home position it goes up and hits the end stops but doesn't stop trying to move up.
Can't really figure out which setting I need for this yet though.

I had exactly the same problem. All of a sudden I got shifted layers on my delta printer, all in the same direction (for me it was towards the z-tower). I tried to tighten belts, lower/higher stepper driver current and different firmware, both Marlin and Repetier, nothing worked. What I did in the end was that I moved the stepper driver for my z-tower to my empty slot (which normally is for a second extruder on RAMPS 1.4) and reconfigured the "pin.h" file in the firmware so that my z-tower motor now is driven from the "E1" slot on the RAMPS board. That solved my problem! I guess it was a hardware problem with either the Arduino or RAMPS board.