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Hi everyone, I installed new pulleys and belts (GT2) on my Ultimaker Original

and - at first - didn't recognized any difference . But when you take a photo through a macrolens

you can see how much difference there actually is:

size: 5a330da12ee69_DSC_039201(1).thumb.jpg.f7be963ebf8763238e337af8a376cd08.jpg

MXL: DSC_0404.thumb.JPG.57313d579c10763aa90e4f4a5cd58022.JPG

GT2: DSC_0405.thumb.JPG.aac8b77e45aa41ab4df79d18b47b81d2.JPG

The other settings where exactly the same, therefore i really really can recommend it to everyone that owns an UMO.

You have to change the steps/mm to 80.00! (thanks )

Have a nice day,

Ataraxis

5a330da12ee69_DSC_039201(1).thumb.jpg.f7be963ebf8763238e337af8a376cd08.jpg

DSC_0404.thumb.JPG.57313d579c10763aa90e4f4a5cd58022.JPG

DSC_0405.thumb.JPG.aac8b77e45aa41ab4df79d18b47b81d2.JPG

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Very nice! The motion definitely looks cleaner.

I have upgraded pulleys on the original belts, and am considering a GT2 upgrade. My heated bed upgrade just arrived, so I'm excited to get that rolling as well.

Where did you get the parts? What sized belts and how many teeth on the pulleys?

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The length is perfect, therefore I do not use tensioners anymore.

I read that - when you use the GT2 belts - there is no need for tensioners at all.

I don't know if that is still true after some hundred prints but at least at first it is.

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hey macua, no - since the diameter is the same as before you don't have to change anything else (but the belts and pulleys) ;)on the other hand i really recommend new x/y-blocks!

chopmeister's design is my personal favourite. i tried some others too but i prefer the easy to print and solid design of chopmeister's:

https://www.youmagine.com/designs/twisterblocks

they also include a GT2 clamp that does not lead to any tension at the belt.

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Great thanks for the info. I have tried ordering the parts, just waiting for Robotdigg to get back to me. Its a strange web store, check out means sending an email to the owner to verify, at which point they send you an invoice.

Looking forward to applying this upgrade. Going for direct drive at the same time too, hopefully see some noticeable improvements.

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@lars86: you can also choose china post (as i did), to germany it was 4 USD

tell them to stick the invoice on the outside of the package, otherwise it will be handed to the customs. shipping was around 2 weeks from china to germany, and and additionally week it was at the customs...

@macua85: mine is also direct driven, i can recommend it. but be careful what kind of couplings you install, otherwise you will have some backlash again. you should easily get some metal bellow couplings (which are backlash free) in china i guess :)

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Have you guys scrutinized the concentricity of the pulleys? That is my biggest concern, because once fastened to the rods, if there is any eccentricity to the cogged surface, the print head motion will have sinusoidal accel / decel instead of constant velocity.

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Well, I spent all afternoon on this. So, first problem...the rods i bought are a different size! They are I think h6, 8mm. So the bearings etc take some force to get on. I got past that however. The bronze guide bearings seem ok, still pretty loose. However, on assembling it all with the new xy blocks, its all super stiff...cant move properly. I'm trying to troubleshoot now. If I loosen the 6mm rod points on the XY blocks, it gets much easier to move around. Maybe its an alignment problem on the print head. The old system was maybe more forgiving?

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hey macua, yes the original ones are f8 (minus-minus-tolerance) and also hard-chrome-plated (as i describe here). it's important for the ease of movement and especially for the original bearings to keep that tolerance (i also ordered h6 at first but had then contact to someone "who knows it better" :D). I had no problems with the linear slide bearing (the bronze ones) and the f8 shafts.

therefore I would suggest to buy new rods again,

or - if this is cheaper - new bearings (maybe linear ball bearings? i also thought about that).

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Well, I spent all afternoon on this. So, first problem...the rods i bought are a different size! They are I think h6, 8mm. So the bearings etc take some force to get on. I got past that however. The bronze guide bearings seem ok, still pretty loose. However, on assembling it all with the new xy blocks, its all super stiff...cant move properly. I'm trying to troubleshoot now. If I loosen the 6mm rod points on the XY blocks, it gets much easier to move around. Maybe its an alignment problem on the print head. The old system was maybe more forgiving?

Macua, the bronze bushings are super prone to being distorted by the XY blocks. If they involve a bolt that clamps the XY block together, it needs to be almost finger tight. I ended up adding some super glue to restrain the bushing while avoiding any real clamping.

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I don't like to contradict @lars86, you may have your reasons, but i didn't faced that problem and I think the only reason to tighten your screws that much is the fear that the screws could loose more and more. in that case I would suggest spring washers, as - in my eyes - everyone should use at moving parts.

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I don't like to contradict @lars86, you may have your reasons, but i didn't faced that problem and I think the only reason to tighten your screws that much is the fear that the screws could loose more and more. in that case I would suggest spring washers, as - in my eyes - everyone should use at moving parts.

Too many variables to just say you can or can't fully tighten the bolts on a clamp style XY block.

Even if you are printing the exact same model as someone else, the calibration of the extruder, XY steppers, flow rate, filament size, etc, means that the size of the bore you print will vary. It's possible that the XY block halves seat against one another before exerting much force on the bushing. It is also possible that the bore touches the bushing first, in which case, a large force can be put on the bushing for a very small torque on the bolt (this is why we love threaded fasteners!)

What can be said without question, is that the bushings are extremely prone to deformation and binding (even the amount of force needed to compress a spring washer). It is an easy test to loosen the bolts and look for an improvement in the force needed to move the print head.

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he should measure the diameter of the printed part for sure,... this is a good example of "separation of concerns". real deviations are not part of the responsibility of the modeler - something he could/should think about are tolerances.

if chopmeister makes a model that fits "in theory", it is up to you an me to adjust the settings (hard- or/and software) so that the reality fits the theory (with some tolerances for sure).

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So I managed to get it working, the problem was indeed the bearings getting pinched. However, I now face my next problem. The holes are not round when it prints circular items. Any ideas on what could cause this? The old setup printed perfectly round holes.

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do you already have installed direct drive? is it still the h6 shaft?

first idea: still too much friction and therefore you are losing steps in - at least - one direction.

 

  • is it possible to you to move the printhead by "two fingers"?
  • is there more force necessary in one direction than in the other?
  • what happens when you increase the steppers current to it's maximum? (see here)

 

second idea: check your pulleys (and couplings), maybe some of them are loose. you can also mark the position to see if they move.

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Hey, thanks for the reply. I am still using the H6 shafts, as the bronze linear bearings seem to have 'worn in' now. I can move printhead as freely as I could on my previous setup, one hand etc. its a curious one, as it appears that all of the pulleys are tight. They certainly are on the h6 shafts as they have some natural grip with the tolerances. I'll mark them as you suggest and see if thats the problem..

If i can't solve it, i'll go back to the belts...but keep the GT2 system. Would it be possible to use the MXL short belts and keep the GT2 long belts, or will I get some step/movement mismatch on the prints? i.e they come out smaller/larger etc than design.

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