Leaning prints? - solved

[daveholbrook 0]

Hi, I'm pretty new to the 3d printing community only purchasing an Ultimaker 2 within the last week.

I've gone through the set up process and everything was going fine untill I came to produce my first print (ultimaker robot). With each layer that is printed the head seems to move along the y axis, printing the next layer out of position resulting in the print leaning towards to from of the machine.

I've tried several different prints and everyone is the same. I've reset the factory settings and set up from scratch but still the prints are all the same.

Is this a common problem? And is this something I am doing wrong or is there something wrong with my machine?

Thanks.

[IRobertI 520]

It could be that there's a pulley or two that is slipping. I would go through all of them and tighten the set screws very firmly. It could be just the pulley on the y-stepper that is causing issues but it doesn't hurt to make sure they are all tight (and it doesn't take much time at all) to make sure everything is solid.

The pulleys are the round cylinders with grooves in them that move the black belts back and forth. On the side of them there's a tiny little screw that lock them in place on the rods. Turn off the power to the printer so it's easier to rotate the screws into a position where you can tighten them.

 

[gr5 2,172]

This is very common with the UM Original which is almost the same design. There are 6 pulleys on the Y axis and the 2 that are most likely the problem are the two on the "short belt" which is the belt that goes to the stepper motor.

Tighten all 6 as tight as possible. Consider marking each pulley and shaft with a tiny dot with a permanent marker so you can see which one is slipping.

Unfortunately one of the 6 pulleys is hard to get to - the one on the motor. You might have to remove the motor to get to it which probably means removing the cover also.

There are other possibilities besides slipping pulleys (with your "lean" description the other possibilities go up from 1% to 30% likely). So consider putting one drop of light mineral oil (baby oil, 3-in-1, sewing machine, or even engine oil but not grease or wd40) on each of the X,Y rods and also with power off push the print head around with your fingers seeing if there is much higher resistance on Y axis. It's possible the Y long belts are too tight causing binding and excessive friction.

Also after tightening the pulleys, if prints are still leaning, look carefully at the Y short belt as it moves back and forth - compare it to the X belt. See if you notice something different for example a twisting and report back here.

 

[daveholbrook 0]

Thanks for both replies. I've tightened all grub screws (apart from the difficult to get to one) but am confident this is not the issue as every one seemed very tight already.

While observing the belts during a print nothing seems to stand out as being incorrect.

However, after lightly oiling the x y shafts it is very noticeable the difference when manually moving the head. Along the x axis the head moves smoothly and freely, but along the y axis it is stiff and tight (infact if you try to push the head in the y axis withing holding the machine with your other hand then the whole machine will move).

Is this something which I can remedy myself?

[daveholbrook 0]

I must also add that now having tried a print after oiling the shafts and moving them manually, the y axis doesn't move at all.

I've slightly loosened the screws which are holding the motor in place and this has freed up the movement manually, but when trying to print the y axis doesn't move what so ever. Have I done something wrong??

[illuminarti 18]

Hmmm, this is an odd one. Does the motor move? Or at least try to move? Is it possible something fell down in between the Y motor pulley and its belt (like a grub screw)? Any strange noises?

I don't think that you could really have 'done' anything to it, no. With the power off, the X and Y axes should move with equal ease.

 

[daveholbrook 0]

Since slightly loosening the four screws which hold the motor to the side panel then they do both now move equally as easy, prior to this the y movement was very stiff. However once the machine is now switched on there is no movement in the y axis.

I can't hear any strange noise and it doesn't seem as of the motor is trying to move, althogugh I did see slight movement at one point. I've not touched anything else for something to have been dropped down there, no. I've trying backing the four screws which hold the motor in place right off and then starting up the machine hoping t see some movement as there would now be little tension, but again nothing.

[gr5 2,172]

You must have disconnected the wiring to the Y motor somehow. You should remove the cover on the larger of the 2 panels underneath. There are only 2 screws holding it on.

The cables are all marked - look for "Y axis" or something like that. The cables are all pretty tight - it was probably on the verge of coming off already.

 

[gr5 2,172]

It says "Y":

 

[illuminarti 18]

I've not touched anything else for something to have been dropped down there, no.

 

One person had a grub screw come out of a pulley and lodge in the motor, iirc. That was the sort of thing I was thinking of.

 

[gr5 2,172]

I'm confused - are you saying the motor can't move it or that your hand can't move it? I guess it's time to loosen the grub screws and see where the problem is. If the long belts are too tight that could be a problem. More likely - something is hitting something in the area of the short belt.

 

[illuminarti 18]

I think that it moves by hand, but only if the motor mounting screws are slightly loosened. And in any case it doesn't move under motor power.

 

[daveholbrook 0]

Manually by hand I can move the head in each direction. It's when I now switch the machine on that there is no movement on the y axis motor. I think it may be as you have suggested gr5 and that a connection has come lose. This may be a connection at the motor end as this is te section where I have loosened the screws to release some tension within the belt. I will take a look at this tomorrow and report back.

As for something falling down into the pulleys illuminarti, I have checked and they are definitely free and move nice and smoothly by hand when switched off. This must be a connection problem with the wires. I guess it's easy enough to get to the motor to check the connection?

[gr5 2,172]

It shouldn't be hard to get that back left cover off but I still think it's more likely on the bottom. But check in either order.

 

[synvox 0]

Hi, if you have loosen the screws holding the y-motor, it will not have enough force any more to move the y-axis, because the short belt will be slightly loose too (it will just slip, when the motor turns).

I too had the problem with the partly stuck y-axis (hard to move by hand), when i received my UM2 (along with some other common assembly issues), and it was getting even worse after some prints until eventually a loud squeeking noise appeared (which i could localize at the y-motor) and i was having the layer shifts in y-axis too.

I had to unmount the left metal cover and the y-motor. The problem was, that the motor pulley was slightly loose and wandered slowly outwards along the motor shaft, just enough that it made contact with the left panel wall and therefore was causing a lot of friction and also the squeeking noise.

After pushing the the pulley back in place (it has to be flush with the end of the motor shaft), tightening the grub screw and putting everything back together, the problem was gone. I could move both directions by hand easily and also the layer shift was gone.

When mounting the motor again, you have to push it down with one hand quite hard while tightening the mounting screws with the other. This makes sure that the short belt is tight.

Kind regards

Neni

 

[daveholbrook 0]

Thank you Neni. I removed the left case and motor as you suggested and you were right, the motor pulley had worked loose fouling on the side panel. With this put back and tightened down everything is working perfectly.

Thanks for everybody's help.

Dave

[mitjabrandt 0]

Dear Ultimaker family,

this is my first post, as a fresh Ultimaker owner for a week now, I am getting frustrated on this same topic. I had printed several test prints and all of them are leaning on the right side. Tightening the motors and shafts is getting me nowhere. Why I have to bother with this issue, my Ultimaker is brand new!

Any new suggestions?

Best regards.

 

[gr5 2,172]

UM1 or UM2? It depends - if you have sudden moves in only one axis and they tend to happen in large amounts (>1mm per layer) and all at once, it is usually a loose setscrew on a pulley.

If the problem is that the part has a gradual lean it means it is missing a step or two on every layer consistently and is usually caused by something rubbing. Almost always the thing rubbing is the short belt or one of the short belt pulleys for that axis. So you want to move those pulleys farther from the wall of the UM to keep the belt from rubbing. Another symptom is sometimes you see black powder as the belt gets pulverized or you hear squeaking on UM2 where pulley is touching the wall. In all cases the solution is to move the pulley closer to the motor or away from the wall. It should be almost touching the motor. On the UM1 if you used the plastic spacers you need to add one washer under each of the plastic standoffs to move the belt farther from the wood.

Can you supply a picture of a "leaning right side" print? And is this a UM Original or UM2?

 

[mitjabrandt 0]

UM1 or UM2? It depends - if you have sudden moves in only one axis and they tend to happen in large amounts (>1mm per layer) and all at once, it is usually a loose setscrew on a pulley.

If the problem is that the part has a gradual lean it means it is missing a step or two on every layer consistently and is usually caused by something rubbing. Almost always the thing rubbing is the short belt or one of the short belt pulleys for that axis. So you want to move those pulleys farther from the wall of the UM to keep the belt from rubbing. Another symptom is sometimes you see black powder as the belt gets pulverized or you hear squeaking on UM2 where pulley is touching the wall. In all cases the solution is to move the pulley closer to the motor or away from the wall. It should be almost touching the motor. On the UM1 if you used the plastic spacers you need to add one washer under each of the plastic standoffs to move the belt farther from the wood.

Can you supply a picture of a "leaning right side" print? And is this a UM Original or UM2?

 

Gr5, thanks for your info. The printer is UM2. I'll check this during the day, here is the photo of the "leaning"

. Thanks in advance

 

 

[gr5 2,172]

Yes - I've seen this before. Something is rubbing. More info on this here - the linked-to post below shows how the wheel (on the Y axis this time) was rubbing the outside of the UM. Your problem is on the X axis but it's the same basic problem.

http://umforum.ultimaker.com/index.php?/topic/4171-ultimaker2-axis-squeeknoise-solved/?p=34362

Removing the metal cover that hides the Y stepper is easy - only a single screw holds it in - it's (very roughly) half way up one of the edges of the white metal cover - if you look along the edge carefully you will see a spot where a bolt is welded to the cover. Then command the Y axis to move back and forth a few times. Does it squeek or is the black belt rubbing? Is there black powder down at the bottom (the belt slowly being converted to dust)? This belt (the short belt - the one going around the X stepper) is almost certainly rubbing and the fix is to slide the pulleys away from the wall. The upper pulley on the rod is easy to move but usually it's the one on the motor as shown in the picture in the above post.

 

[mitjabrandt 0]

Well .... that worked for me!

Thank you very much for your help.

The problem was in the pulley as you said, it was too close to the wall. I have removed the cover, removed the motor and moved the pulley closer to the motor. Now is printing straight!

So thanks a lot again!

Best regards,

Mitja