Flipped pully to get Y-Axis central. Is this OK?
I have started my build and its going fairly smoothly.. But I am having problems alligning my Y-Axis belt
When built per instructions, the belt runs against the lip on the pulley, even if I put it as close to the motor as possible.
I am not sure if this picture shows the problem clearly. The belt is running against the right edge of the pulley and I already have the pulley touching the motor (Which I know is bad). And there is no way to get it central. In order to fix this, the motor really needs to move 2-3mm to the right and I was thinking of making a spacer to make that happen.
But I tried something that worked which was simply to flip the pulley.. Now with the grub screws on the outside of the shaft I can adjust it either way and get it to run dead centre..
Is there any problem doing this?
Jon
Re: Flipped pully to get Y-Axis central. Is this OK?
The only issue I would see would be alignment with the attachment on the bottom of the y-carriage.
If your front/back pulleys and your y-carriage attachment point are dead linear (slide the bed fully forward and back to check), I'd think you are ok.
If there is deflection (the bed attachment is not in line between the pulleys and you see horizontal deflection on the belt), then I would avoid this. Something else is likely going on.
Your other variable on this is the rotation around the z-axis of the motor/pulley assembly. You may be able to shim the pulley side of the motor slightly away from the frame to get the belt centered.
Re: Flipped pully to get Y-Axis central. Is this OK?
Actually.. I looked again and that didn't solve it.. With the pulley flipped over and the belt running in the center, the belt is no longer tracking straight..
So it seems that either something skewed.. Or the motor does need to move.. A couple of mms...
Has anyone else encountered this?
Re: Flipped pully to get Y-Axis central. Is this OK?
Actually.. I looked again and that didn't solve it.. With the pulley flipped over and the belt running in the center, the belt is no longer tracking straight..
So it seems that either something skewed.. Or the motor does need to move.. A couple of mms...
Has anyone else encountered this?
Yes, I had exactly the same issue. I reworked and reprinted the motor mount adding 2 mm to the thickness to move the motor over. Worked fine. 😀
Re: Flipped pully to get Y-Axis central. Is this OK?
Actually.. I looked again and that didn't solve it.. With the pulley flipped over and the belt running in the center, the belt is no longer tracking straight..
So it seems that either something skewed.. Or the motor does need to move.. A couple of mms...
Has anyone else encountered this?
Yes, I had exactly the same issue. I reworked and reprinted the motor mount adding 2 mm to the thickness to move the motor over. Worked fine. 😀
So I might just print up a 2mm 'spacer' on my Printrbot just to move the motor out and and see how that goes.
Re: Flipped pully to get Y-Axis central. Is this OK?
Make sure the screws are long enough to just add a spacer. That’s why I reworked the part. I recessed the screws by the same amount I increased the thickness to keep screw engagement the same.
Re: Flipped pully to get Y-Axis central. Is this OK?
Make sure the screws are long enough to just add a spacer. That’s why I reworked the part. I recessed the screws by the same amount I increased the thickness to keep screw engagement the same.
Cheers.. plan on using some 12mm screws i have...
Re: Flipped pully to get Y-Axis central. Is this OK?
That seems to have done the trick. Looks li,e the mount for the motor could do with a tweek.
Now with my 2mm spacer and some longer screws, the pully and belt now seem better aligned.
Edit: I did try to add it, but this forum does not allow 'STL' attachments, which is a little odd..
Edit2: Try this
ftp://jweaver.ddns.net/yaxisspacer.stl
Re: Flipped pully to get Y-Axis central. Is this OK?
Excellent! 😀
This was my reworked part version. Printed it in orange PETG just because I could...
Re: Flipped pully to get Y-Axis central. Is this OK?
Excellent! 😀
This was my reworked part version. Printed it in orange PETG just because I could...
I would much prefer to have printed the entire mount.. But I only have PLA and figured that I would prefer the original mount with a 2mm slither of PLA.. Rather than build the whole thing out of PLA and suffer the consequences later...
I am quite surprised we needed to do this.. Even if it doesn't affect everyone, this "mod" makes the shaft more central to the patch of the belt and gives much more adjustment possibilities of the pulley.
Re: Flipped pully to get Y-Axis central. Is this OK?
I am appalled this is even happening. 2mm is a LOT, and you would think that would be an obvious problem for others. Are we sure there isn't something else going on that is causing this for some?
Re: Flipped pully to get Y-Axis central. Is this OK?
Adding some color to this. I have been struggling with belt alignment on both X and Y axis and they are both issues with one side being slightly off axis, so the belt naturally grinds on the shorter side.
For the Y-axis, in my case, the stepper itself had a small gap with the frame on the back side due to the mount being too flexible (note: my belt tension is in range), as discussed on this support ticket:
http://manual.prusa3d.com/Answers/View/852/Y+Axis+Assembly+Motor+Holder
What I did was to just zip-tie the back of the stepper to the frame and voila - belt perfectly aligned and no need to move the stepper or flip the gear.
I may reprint the part in something less flexible at some point.
Easy test: take the Y-axis stepper and wiggle it. If it's like mine, there is a lot of flexing of the mount, too much IMHO.
Re: Flipped pully to get Y-Axis central. Is this OK?
For the Y-axis, in my case, the stepper itself had a small gap with the frame on the back side due to the mount being too flexible (note: my belt tension is in range).
I did have this and thought it might explain the issue, but when i tightened the screw, the motor sat flush to the frame.
It came back when i added my spacer, but that turned out to be something i managed to trap under the mount..
Mine sits flush with the frame and is very ridged so that doesint explain what i am seeing.
Re: Flipped pully to get Y-Axis central. Is this OK?
Has anyone else encountered this?
Yes, I had the exact same problem as well. Couldn't find a thread on it at the time, so I assumed maybe it was just me.
I fixed it by adding small washers in between the Y stepper motor and the motor mount. That gave me the extra ~1.5mm offset I needed to get the Y belt aligned.
This, in addition to the defective X idler part causing X pulley/belt misalignment, is surprising and disappointing. We're not talking about parts used for routing cables or something, these are parts that determine the alignment and performance of the X and Y axis drive belts. You don't get any more fundamental than that.
Re: Flipped pully to get Y-Axis central. Is this OK?
Has anyone else encountered this?
Yes, I had the exact same problem as well. Couldn't find a thread on it at the time, so I assumed maybe it was just me.
I fixed it by adding small washers in between the Y stepper motor and the motor mount. That gave me the extra ~1.5mm offset I needed to get the Y belt aligned.
For anyone encountering this same issue during your build, I have written up some additional insights and the "fix" that I came to in another thread: https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/fine-tune-your-mk3-y-axis-t13851-s60.html
Re: Flipped pully to get Y-Axis central. Is this OK?
the new parts are on GitHub now print them out
Re: Flipped pully to get Y-Axis central. Is this OK?
the new parts are on GitHub now print them out
The parts you refer too do not address this issue.
Re: Flipped pully to get Y-Axis central. Is this OK?
the new parts are on GitHub now print them out
The parts you refer too do not address this issue.
Re: Flipped pully to get Y-Axis central. Is this OK?
the new parts are on GitHub now print them out
The parts you refer too do not address this issue.
I agree, they do not. The newly posted R2 Y-axis parts are basically identical to the R1 parts, with the exception of a few tolerance adjustments. I don't really see how those changes could impact any of the Y-axis issues raised in any threads on the subject. That said, PRUSA never mentioned they were fixing any Y-axis issues in R2, so I was surprised to see new Y parts posted at all.
Re: Flipped pully to get Y-Axis central. Is this OK?
oh I did not realise this thought they where a fix my bad