Print Goes Askew Around the 4th Layer

[Wayneman]

I'm currently having an issue with a Velleman 8200 Printer which has given me some really outstanding parts over the past few months.
I'm running Marlin Firmware and slicing with Slic3r 1.0 the latest version.
But all of the sudden, 75% of my prints are shifting to the left or right on the X axis around the fourth layer. Now what's weird about this is that not all parts go askew, and one part would do it in the exact spot for ten prints in a row. Now this is a part that I have printed dozens of times flawlessly in the past.....But today, I ran the part again and its going askew in the other direction...to the left now...not the right like it did yesterday. One other part went askew the for the first couple attemps and then printed fine on the third try. I've tried tightening my belts and turning up the current to the X stepper motor ever so slightly.....same thing happens. I was thinking it could be in the "slicing" but I tried printing with another slicer on another computer. Still no luck. This same kind of thing happened to me on my PrintRbot about a year ago. I found that turning up the current to the X stepper fixed the problem (at least, I think it did) but what gets me, if it's a mechanical flaw how can it go askew in the exact same layer each time. I carefully monitored the print hoping for clues but no, skipping or grinding....I've run out of ideas..
Any help would be awesome.
Thanks again.
W.

[DrLuigi]

Well i know someone else with a K8200, He also had this problem,
There are number of things that can get this malfunction,

Example:
The belts,
The rods that arent as smooth anymore,
The current,
Your motherboard getting to hot
(My best guess that it would be this, As Velleman doesnt give Heat dissipation blocks to paste on the chips, So i would advice to get a Fan on it, example 60-120mm i use 120mm and works fine, and perhaps even a few dissipation blocks)

The chance of it being your Slicer is almost zero, The only thing the slicer could do is giving it to much speed, example 250mm/s will probably be overkill for a Velleman.
And thats about the only thing i could think about at the moment that the slicer could do wrong.

I hope you will get it fixed asap with some of my tips, As it can of course be something else, But these were the points that are giving this problem most of the time.

I had for myself this skipping problem when the current was 0.2v off, so you do have to get it accurate. No rough guesses without a multimeter.

[Wayneman]

Hello Dr. Luigi,
Thank you for your advice. I'm using a RAMBO 1.2 Circuit Board. All the current adjustments are in Configuration.ADV.h ...software controlled.
I haven't yet put the multi-meter on to check ...but that will happen today.
The motors on the Vellemen run very cool. Just barely warm to the touch after an hour and a half.
I really don't think it's a "heat issue". I tried printing a tall cylinder about 30 mm round and 140 mm high.
It took about 1 hour and came out perfect.. I then loaded a couple of other parts. One is a "mouthpiece" for my prototype Xharp. appox 160 mm x 40 x 10 mm high. and a "manifold" approx same mm's. both prints go askew. ...the mouthpiece, second, third or fourth layer...same on manifold.
I did try slicing with "Kisslicer" and the same thing happened. This machine is only 4 months old and blows the printRbot's out of the water...when it's working well. My belts are in great shape...(I have new ones on order) just in case . So how can one part print perfectly and then another goes askew.....that is the mystery.....It rules out ...rods, belts, current, heat, ???? Remember this is a brand new Rambo 1.2 motherboard.
Thanks again for your help....I'll check everything again.
W.

Well i know someone else with a K8200, He also had this problem,
There are number of things that can get this malfunction,

Example:
The belts,
The rods that arent as smooth anymore,
The current,
Your motherboard getting to hot
(My best guess that it would be this, As Velleman doesnt give Heat dissipation blocks to paste on the chips, So i would advice to get a Fan on it, example 60-120mm i use 120mm and works fine, and perhaps even a few dissipation blocks)

The chance of it being your Slicer is almost zero, The only thing the slicer could do is giving it to much speed, example 250mm/s will probably be overkill for a Velleman.
And thats about the only thing i could think about at the moment that the slicer could do wrong.

I hope you will get it fixed asap with some of my tips, As it can of course be something else, But these were the points that are giving this problem most of the time.

I had for myself this skipping problem when the current was 0.2v off, so you do have to get it accurate. No rough guesses without a multimeter.

[Wayneman]

Hello Again Dr. Luigi
As it turns out somehow my calibration for my Z axis was slightly off. Since I tweeked it she's cookin' with butta'.
But now, I've got another little hang up.....Whenever I hit "Run JOb" button....it takes up to 3-5 minutes before the job starts.
From Day one....it always was almost instant....Any thoughts on this one ?
Thanks again
W

Hello Dr. Luigi,
Thank you for your advice. I'm using a RAMBO 1.2 Circuit Board. All the current adjustments are in Configuration.ADV.h ...software controlled.
I haven't yet put the multi-meter on to check ...but that will happen today.
The motors on the Vellemen run very cool. Just barely warm to the touch after an hour and a half.
I really don't think it's a "heat issue". I tried printing a tall cylinder about 30 mm round and 140 mm high.
It took about 1 hour and came out perfect.. I then loaded a couple of other parts. One is a "mouthpiece" for my prototype Xharp. appox 160 mm x 40 x 10 mm high. and a "manifold" approx same mm's. both prints go askew. ...the mouthpiece, second, third or fourth layer...same on manifold.
I did try slicing with "Kisslicer" and the same thing happened. This machine is only 4 months old and blows the printRbot's out of the water...when it's working well. My belts are in great shape...(I have new ones on order) just in case . So how can one part print perfectly and then another goes askew.....that is the mystery.....It rules out ...rods, belts, current, heat, ???? Remember this is a brand new Rambo 1.2 motherboard.
Thanks again for your help....I'll check everything again.
W.

[DrLuigi]

Aint completely sure, perhaps its just not heated up enough?
If its 1c off it will just wait till its on the right degree and wait 15 seconds i believe, or atleast mine used to do that.