Layer shifting/offsetting

Vertex 3D Printer Vertex - Issues while printing
1

I expected that my printer would sometimes make misprints, but i didn´t expect the succesrate to be less than 10%, I am having huge problems with offsetting/ layer shifting and haven´t produced any “successful prints” since the very first thing i made(a low-poly totodile) and a 1,5cm^3 test-cube that i since haven´t been able to replicate.

During printing, especially when the printhead is attempting to move fast, the printer will produce a loud rumbling noise, after which the print will be offset, usually to the left.

A video of me manually controlling the printer:
https://dl.dropboxusercontent.com/u/48208874/VERTEX%20Settings/20141214_123929.mp4

Attempt to print another test-cube:
https://dl.dropboxusercontent.com/u/48208874/VERTEX%20Settings/20141214_124517.mp4

I didn´t bother to finish the print, but heres how it looked and how it was supposed to look:

I have de-assembled and re-assembled step 16-17 twice now, putting alot of attention into making the
pulleys and rods as perpendicular and parallel as possible, but i am not sure it is enough.

I have oiled the rods again, updated the firmware to M1, V1.1,H1 - restored the failsafe and stored in memory, i have tightened all the pulleys made sure the motors are securely fastened and their belts as tight as possible, and made sure the printhead is securely assembled.
…and i have made sure the printer stands on even ground with a spirit level.

The problem is NOT the filament being to tight, I have mades sure there is slack between the spool and the extruder, and the spool can move freely.

I have notices some “black dust" on top of two of the motors, i guess this is either from the belt or the bearing clamps, does this perhaps mean i have tightened something too much? - i have made sure that the pulleys and bearing clamps can move effortlessly up and down the rods BTW.

The 4 nuts in the back of the bearing clamps, seems to unwind when the jerking occurs - maybe i should use locking nuts instead?

NOTE, i am missing 2 clasps that hold the buildplate onto the Z-axis, I was missing 2 4M-3mm screws in the kit

  • and replacements are on their way here, but I doubt that is what is causing the problem - the buildplate seems to stay put during printing with no problems.

I haven´t checked the the temperature of the 1.5A driver boards - as suggested in the FAQ, since I can hear it is a mechanical problem, so I don´t think they are the problem, but please tell me if you disagree with that assessment.

Also, the text on the display is very dim, is there a potentiometer somewhere i can adjust the contrast with?

Lastly, this may be due to the exact same thing, but circles aren´t coming out circular but rather oval in shape.
I am running both Windows 7 and Mac OS X on laptop, but i would like to cast my vote to have a mac version of the software released, or just a document detailing how to get the vertex printer settings working with the repetier host version on the mac.

It has come to the point where i am just trying to move the pulleys and rods - the printhead sit on, randomly back and forth, with the hope of finding a position that is correct enough - but to no avail.

on a positive note, I am happy with the 2 successful print i have produced so far, i am very pleased with the details at 0,1mm and looking forward to working with 0,005mm.

I really hope someone in here can help me, since I am at my wits end here.
Thanks.

P.S. I am sorry if the text is a little unclear, but english is not my vernacular.

2

You obviously have an issue on you X axis (grinding on the right). I had the same issue on the Y axis and I got it right doing what is suggested in the manual : “If the resistance increases in any way when you get close to the any of the panels with the printhead, it is possible that the distance between 2 of the XY CARRIAGE CLAMPS is not correct. You can try to fix this by pushing or pulling these together a bit and seeing if the problem improves”. Actually I just had to move the clamps a fraction of a millimeter apart to get the axis moving freely.
It’s the trickiest part of the assembly.

Your Z axis seems to be grinding too. Are all your linear bearings Ok? I had a bad one missing some balls and my Z axis was grinding too.

3

I have experienced about the same issues, although I have not even started to print. I was quite unhappy with the movement of the axis after I put them together the first time (this is my first printer). I decided to power up the printer and tested axis movement first. My Y-axis started to lose steps when I moved closer to the end of the rods. X-axis was better not not perfect.

I decided to remove all the rods and xy-carriage and start over again.
This time, I first wanted to know the exact width I needed in between the bearing clamps. I mounted both rods without the print head and by trying/adjusting I found the proper length where the xy axis moved smoothly and wrote down the distances. I then took it all apart again and repeated the assembly with the print head included (using the newly found distances for the clamps). The movement became much, much better!

I then carefully aligned the xy-carriage rods to the 8mm rods, not to the frame (which I did the first time following the instructions). I still feel quite some restrain when I try to move the axis by hand but the motors now move the axis without losing any steps.

Later, I connected the printer to Repetier Host and tested movement on different speeds. I still found some instances where I lost steps (close to home position and during the first mm of movement), but I could get rid of that completely by changing the Acceleration settings on the printer (6000 ->1500).

The only ‘worry’ I still have is the sound that my steppers make. From what I read is that a stepper might become more noisy when it’s driver current is set too high. I do not yet know how to test that. Does anybody know if they shipped with the correct current setting?

Erik

4

The stepper drivers are calibrated from the factory, but you can check their calibration using the instructions here:

http://manuals.velleman.eu/article/1-frequently-asked-questions-39.html#SHIFTEDLAYERS

The black dust you see is from two belts rubbing together. This can be alleviated by either moving the pulley a bit or by tilting the motor ever so slightly so the small belt moves away from the longer belt.

Could you check if the top tube bearing and the bottom tube bearing are correctly seated in their plastic covers and if they are at a 90° angle? and if the distance between their centers is 18mm?

I know this is a rather annoying problem but the problem is almost always mechanical. Like you said the calibration of the X & Y rods is very important. Also check if your belts are not to tight.

Also make sure that all the rods are lubricated well enough.

5

Hello

I did have the same problems with the y-axes !
The y-motor did sometimes wrong steps.
I tighten the (all) belts not so strong,and now
the printer works verry good !

Please excuse my not so good english !

Regards,Georg

6

My solution was:

  1. Check voltages and VXY-Jrtk
    2.swap motor chips X–Z
    3.Reduce Acceleration setting down to 3500
7

Hello everyone, sorry for not posting sooner and thank you for all the suggestions.

I am afraid I took the stupid way out, and did a lot of the suggestions in 1 go, instead of doing them 1 by 1, so now i don´t know which solution worked the best, oh well - i´ll try to figure that out later.

I loosened the belts a little bit and tilted the motor back, I haven´t noticed any more black dust for now, but it is still to early to tell.

As suggested by h60 and rotomoto i set the acceleration down - i had previously tried setting it down to 3000, but that didn´t help - so i decided to set in on 1500, which seemed to help, so now it is at 1000 :slight_smile:

I also changed the length between the XY clamps like raby suggested, this also helped a lot even though the distance was exactly the same as recommended in the instructions - I triple checked, it helped finding the exact length after figuring out how to adjust the distance without having to remove the printhead from the printer - a process that took hours!
This is something i had´t thought of doing, so thanks a lot raby, you said you read this in the manual - where exactly, I seem to have missed it completely?
Also, thanks for pointing out the noise from the Z-axis, I haven´t checked the bearings, but it should be said that i haven´t oiled the 2 350mm ø10 rods in the back - is it safe to do so? how often should i oil the different rods?
The first thing i´ll try is to re-oil the threaded rod - I might not have done a proper job the first time.

Anyway, these suggestions have reduced the grinding significantly, re-oiling the XY rods got rid of the rest it seems, however, now there is a new problem - after finishing each layer the Z-axis will go down a bit and the printhead will go about 4cm to the right for a second or two, then come back and resume printing, this reduces the quality of the print and it takes a lot longer - Why does it do that?

A video can be found here:
https://dl.dropboxusercontent.com/u/48208874/VERTEX%20Settings/20141223_155627.mp4
and here:
https://dl.dropboxusercontent.com/u/48208874/VERTEX%20Settings/20141223_161157.mp4
Notice how the LCD says the heatbed i 5-7 degrees…but i have no heatbed?

Lastly, i have also figured out how to make the reading on the LCD more clear - i had completely forgotten what i had read in part 1.Instructions about manipulating the trimmer, with a screwdriver - my bad.

8

I think what you are seeing is caused from Cura.
Since you are printing such a small part Cura will wait for the plastic to cool before the next layer.
Try printing a larger part.

The shifting looks like the screw that holds the pulley on the motor may not have been tighten.
I know it is a hassle but you may want to remove the motor and make sure the screw is tight and on the flat part of the shaft.

9

What you say sounds plausible, i´m sure it is a software issue, though the printer started doing it today while i was attempting to print arguable my biggest part yet, and it hadn´t done that before.
But as you suggest, i´ll try to print something bigger.
Don´t mind the layer-shifting - the video was taken prior to me re-oiling the XY rods, but i haven´t checked the screws in the stepper-pulleys - probably a good idea to do that anyways, thanks.

10

@Azidus: while I have previously set the acceleration to 1500 (or lower) to get proper movement without losing steps, it also lead to 'stringing (read here). But as I tuned all rods quite precisely now (read here) I could switch back to the default 6000 again which eliminated the stringing. Also note all my rods are lubricated and move without enormous friction.

Erik

11

I am also having a lot of trouble with shifts in x and y directions.
All suggested solutions tried. Thanks all!

Also the pulleys might be redesigned to increase set screw thread length?