X "Walking" .3mm with each layer?

Hi all,
Every now and then this issue pops up and I have not found a "definite answer" to the problem. Could be me so correct me if I am wrong and please point me to the answer.
Here is the story:
Slanting as in posts above but no mechanical problems..
Happens on several printers. One with nema23 and threaded rods as drive train. One with belts and 2 Prusa i3's with braid line.
BUT it only happens when the part is larger then 117mm (??)
I can print any parts that have an x or y smaller then 117mm perfectly on these printers.
I can print the parts on any part of the bed and at any speed I set the printer at without loosing steps.
As an example I print the large wades herringbone gear anywhere on my table and no problems at all.
I have made up some test files of a simple rectangle and printed slowly and fast.
I have changed everything I can think of in the firmware but no change.

The issue happens at layer change as in post above.
I tried to add the delay but no change. (Maybe I added it in the wrong place....been some long nights)


Firmware tried: Marlin (I normally use this)
Sprinter
Repetier

Host software: Pronterface and Repetier

Slicer tried: Kisslicer, Slic3r and Skeinforge

Hardware is Arduino with Ramps 1.4 and Pololu drivers

Checked vref on drivers.
Have active cooling on drivers with heatsinks

Most parts I print are way smaller then 117mm so it does not affect my prints BUT why does it slant above 117mm?

Have attached some test files for those who are willing to try and report back.
117mm file prints ok
118mm and above slants
150mm file slants

The critical point is somewhere between 117 and 118 both X and Y
Rotate part in slicer to test Y axis

Any help on this much appreciated.


Regards
Jan

So you are saying you have the same problem with three types of mechanical drive, three different firmwares, two hosts and three slicers? And always 0.3mm per layer?

Wow that is so weird it is spooky.

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[www.hydraraptor.blogspot.com]

What layer height are you using? Does the angle of the slope change with different layer heights?

What happens if you rotate the object 45 degrees?

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[www.hydraraptor.blogspot.com]

Quote
nophead
So you are saying you have the same problem with three types of mechanical drive, three different firmwares, two hosts and three slicers? And always 0.3mm per layer?

Wow that is so weird it is spooky.

Hi nophead,

Yes it is driving me crazy at the moment.
My layer height is 0.2mm as I use 0.3 nozzle right now, but the problem is very weird indeed. Will try different heights and report back.
As I said before I normally don't print over 100mm parts so the problem does not show up..
I will try to do some different layer heights and report back.
What really gets me is that I can run at snail pace, heat sinks and fan and cool drivers and all "looks and sounds ok" but as soon as the layer change happens it is skewered a smidgent (same every layer). I need to double check the 45 degrees rotation and see what happens.
And why at around 117-118mm?

When I get back from work I'll do some more investigation/ testing.

Thanks for your reply

Regards
Jan

Quote

And why at around 117-118mm?

When it is independent of position, mechanical drive system, firmware, host and slicer the only explanation I can think of is a small discontinuity in the space time continuum in your house

Edited 1 time(s). Last edit at 11/04/2013 04:39PM by nophead.

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[www.hydraraptor.blogspot.com]

Quote
nophead

Quote

And why at around 117-118mm?

When it is independent of position, mechanical drive system, firmware, host and slicer the only explanation I can think of is a small discontinuity in the space time continuum in your house

Quite possible....I do seem to loose track of time when I "play" with these printers.....but my i3 is not the Einstein variant...


I will concentrate on my i3 to see if I can find the solution as it is easy to access in regards to electronics and drive train.
But this is what I have done so far on my i3
Tried 3 different firmware
Tried 3 different slicers
Tried 2 different hostware

All on same machine just to see if there was a difference. And I have changed any setting I can think of.

I am printing very nice parts on this machine and speed can be from slow to fast and no issues, as long as the part is less than 117mm in X or Y.
Layer height is 0.2mm.

Things I will try next:
1) Change layer height
2) Create the file I try to print using various CAD applications (maybe this is an excuse to learn OpenSCAD).
3) Rotate the file 45 deg.
4) Print a file with base less then 117mm but larger above (Like a vase)
5) Continue to google.....
6) ...
.
.
666) Call a priest..........

If anyone could try to print the files using a printer with Arduino 2560 and Ramps 1.4 and report back that would be great. And if anyone does experience the same then I would love to hear from someone that could print the files using a different board (Rambo, X3 or any other) and report back.
Thanks in advance.

The printing takes only a couple of minutes.

Regards
Jan

Have you tried a different Arduino? Although rare, it is possible to get problems in the MCU such that a bit in one register is communicating with another bit. In this case it may be something like the counter for layer toggling the step output. That is, not a software or firmware problem but a hardware problem.

Mike

Hi all,

I have had some time to clear my head and the problem I have is NOT electronics or software.
It's my own stupidity. (Nophead... I think you're right...need a new... and a bigger house)
In regards to my two old machines I have had a good look at them (3hrs....I was not going to, but had no choice....) and they are not as bad as I thought after first run. They have a timber frame and needed some adjusting before they where back working ok again after being retired for a while. Just coincidental that they slanted on first try and I was just in too much of a hurry when I did my first test. (Could not see the trees for the forest)
Don't bother testing with the files I posted. They will turn out good.

Lesson learned? Well, don't rush when you try to test and solve a problem. (And use your head.... )
I will come back later with information when I have resolved my problem.

Thanks again for your replies.

Regards
Jan