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Lars Eric Wingfors

Ultimaker Original Plus Belt Problems

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Hello, 

I assembled an ultimaker original plus I ordered a week or so ago, and some of the belts labeled "B300MXL" are rather loose(the long belts). They allow the wooden blocks to slip on the X-axis completely. The printer head does not move left or right almost at all. The Y-axis seems fine, very small slipping if it is at all, when i go into the controls and move it by 1mm all the way back it still has about 2mm of movement back after it hits the switch.  I dont assume this is how it is supposed to be right after assembly, by that i mean something is wrong with the parts. Is it possible for me to contact ultimaker and have them send me new belts, or is there a simple issue im not finding.

 

I tried adding tension to the belts via a small amount of tape on the pullies. This resulted in great tension and the ability to print,  but the prints were not coming out right. Each layer would move out to the left a small amount as it went up. (maybe this is some other problem but i dont think it is). It is possible because these are labeled timing belts, that the tape is causing it to go out of time, and that is messing up the print. But watching the motors closely, i did not see any slipping on the pullies.

 

I have fiddled with the alignment of the pullies to no avail, they are as straight as they are going to get trust me.  

 

I find it odd that there are no tensioners for these belts at all, it would seem to me that this problem would be prevalent due to lack of tensioners but i didn't see any other threads right of the bat.

 

Any help would be greatly appreciated. I hope its just some little stupid thing i did that i can revert, but i do not believe it is. 

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Something must be really wrong if the belts are that loose. On mine, before I switched to GT2 belts, they did not require any additional tension.

But there are tensioners supplied with the printer...4 small spring-tensioners.

Although based on your description I don't think they are enough.

I would contact the reseller and ask for help or new belts.

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I'm not sure what the correct part number is for the belts but if the Y fits and the X doesn't I'm going to guess that you have the right parts.  My belts were also a bit loose but not quite as much as yours.  There is a screw in the wooden block that you can use to tighten the tension on the belt a certain amount.  But that requires a lot of disassembly work.  Instead if you can get some wooden clothespins with the spring - that spring I'm told is perfect for a tensioner and what is found inside the UM2 blocks (maybe?).  Place it at the opposite point on the belt from the block.

 

As far as losing steps on each layer - that problem is indeed unrelated.  It is giving you leaning prints, right?  That is caused by either the short belts rubbing against the wood (it can be subtle - look to see if the belt twists opposite directions when it reverses direction) and the fix is to add a shim or spacer to move the belt another 0.4mm away from the wood.

 

But much more likely your set screws are not tight enough on the pulleys - particularly the 2 on the short belts (on the motor and on the other end of the short belt).  Tighten the hell out of these set screws.  In fact you may have gotten alternate (shiny) set screws among your kit that are pointier and work better than the default ones.  But I just stuck with the default ones (black) and tightened the hell out of them.  You should be tightening these more than you think you need to.  Your tool should be twisting slightly.  If you were to use an L shaped allen wrench your fingers would be hurting after.  More info here:

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#leaning

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I can get tensions on the belt by wrapping a very small amount of tape onto the toothed part of the pulley, the tape conforms to the shape aswell so as long as i dont put to much it still works. I will try and get some cloths pins and see if that works well bc im sure the tape isnt a permanent fix. 

 

 As for the leaning if that isnt to do with the tension of the long belts then thats good, bc i should be able to print correctly. 

 

I just went into blender and exported the starting cube to test the printer after i assembled it and that is what is coming out. 

 

I will follow your instructions @gr5 and try and get them away from the wood a tiny bit and tighten them down alot. 

 

Any thought on why at the end of the print it went wrong in the X axis like 3 layers?

1516209263853783409326.jpg

1516209281424715738068.jpg

15162092958491202751546.jpg

15162093202601027053202.jpg

1516209403682659210233.jpg

15162094295391369977115.jpg

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I assume you mean "set screws" and not "tensioners".

 

The amount of acceleration can be different on different layers depending on the movement path that gcode commands.  It's complicated.  Just tighten those set screws.

 

Note that you could print these tensioners also: 

https://www.thingiverse.com/thing:19892

 

If you push the head into a corner and pluck the long belts you can use a tuning app and the pitch should be around 100 to 200Hz.

 

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When you get these kinks solved, send us a photo of a print so we can give you more advice as you are almost certainly going to run into two more problems.  In fact here are 2 pieces of advice:

 

Tighten the feeder screw more such that the spring is around 10mm compressed.  You want the knurled wheel to bite into the filament visibly.

 

Level the bed closer to the glass than UM suggests such that the filament squishes quite a bit on the bottom layer.  This helps it stick 10X better.

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Ive got all the belts tight, to about 160hz on all four. When i said i had no tensioners i meant that for the person above who claimed that some came with the kit. But i tightened down all the set screws on all the pullies, specifically the ones you were saying to. But the objects still come out leaning forward and slightly leftward. I also did both of your recommendations, of leveling the bed closer and tightening the Feeder spring. 

 

Is there anything else that could be causing this? None of the belts are slipping, before i aborted the print i watched all 6 belts and none seem to be slipping anywhere.  

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How much friction is in the gantry?  If the machine is turned off, you should be able to move the print head around by grabbing it directly and it should take no more than a pound or two of force (and uniform) in any direction - the primary resistance is normally only the notchy feel of the stepper motor turning..  Perhaps your have a bad alignment of the gantry causing too much friction?  or a tight bearing?  If either, the motors could be losing steps, but this would be drastic and the should be audibly noticeable.  It is easy to check.

 

So both pulleys associated with the short belts have been tighten well? and also the primary drive pulley on each of the X and Y axis belt shafts?  All the pulleys need to be tight really.  Not so tight that you strip the screws or wrench. It really is a matter of feel that all mechanics learn by experience.

 

I think the UM+ slider blocks are the same as on UMO.  If so, there is a belt tensioner built into them although it leads a bit to be desired.  However, mine are still in service after 5 years.

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Every pully is tight. About the gantry though, its not like i can grab the head and move it in a circle easily. I don't see how i would be able to since im moving it from one spot causing torque on the shaft in whatever direction I'm moving, the motors bring it around by both edges of the shaft so it should do it easier. There isnt much friction when i go left right, forward back, But there is a little when i get close to the walls bc of the belt having tension. 

 

Ive been using the controller to move it by 2mm (it says 1mm in the controller but it goes up by 2 units, and when i put a ruler under the head i could tell it was going by 2) in the x and y axis and ive noticed that it is actually slipping a smallish amount, it doesn't go all the way to the edge and on the way back it doesnt click the switch, it gets close on the x-axis, like less then 6mm on both ends. But on the y-axis its like 20mm. 

 

The belts are pretty tight to be honest, i can make them tighter but its gonna cause alot of friction on the blocks, is that okay? I mean i guess i want lots of friction but its getting hard to pull the belts that tight and get the axels in the bearings. And @mastory your saying there can be too much friction on the blocks so idk how tight i can/should put it.

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If you feel the belts are tight by the descriptions given, don't over do it.  I've heard of belts being stretched from use or more likely installed too tight.  I think some people have attempted to improve backlash issues beyond diminishing returns by over tightening.  You want them taunt, but not stretched.

Edited by mastory

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No if i remove the tape, it doesnt move in any direction basically. I know its not a long-term fix, im just trying to get it to work so I can try and print some of those tensioners. I will remove it once i have something else to tension the belts but the tape conforms to the teeth on the belt and pully and i have nothing else. Im getting some clothespins tomorrow and im going to use the spring out of them like someone above recommended, but if i can get it to print those ones i won't have to go get the pins. 

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I dont believe there is any real kind of tensioner in those blocks, the top of the clamping part touches the belt and the key part pushes it downwards to clamp the shaft coming from the print head?

There is no spring or anything, there isnt anything pushing it outwards to the belt besides the weight of the print head, and then that is being stopped by the key piece.  Am i missing something here for these parts?

 

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I can't seem to find a good picture of the slider blocks.  Are yours made up of a stack of plywood pieces?  If so, the center piece pivots and is meant to clamp into the belt, thereby adding tension.  A screw captive in another piece pushes against the swiveling piece, locks the belt, and retains the tension.  I think this area isn't assembled right causing your problems.

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Yeah.. I missed this... Im sorry for taking peoples time to help me when i just missed something, Thanks alot to you and @gr5 for trying to help. I was severely confused as to why it would work how i had it set up, i was thinking there is no way this is how it is supposed to be. I dont know why i didnt go back and look at the manual.. Im gonna fix this and get back in here to confirm if it is completely fixed. image.thumb.png.efb42348778299bbbe2b7fd6465dc68d.png

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