Y-axis Rough Movement
Hi all,
I recently got my kit and have begun assembling it. I have completed it up to the 11th step on the X-axis assembly ( http://manual.prusa3d.com/Guide/3.+X-axis+assembly/299 ). However, after assembling the X-carriage I was comparing the smoothness of the movement compared to the Y-carriage assembled before. I can easily move the X-carriage with one finger with minimal force and I would consider it very smooth.
However, when I move the Y-carriage it takes probably 3x the force to move around with one finger. There is also an increased amount of force needed as I get close to the Y-axis motor. I am worried when I was assembling the Y-carriage I may have over-tightened the nuts and potentially deformed the bearings (as warned in the instructions), although visually I do not see any issues.
So I am wondering, should I be expecting the Y-carriage to move just as smoothly as the X-carriage? (Perhaps because there is no belt attached to the X-carriage yet that may cause a difference)
If there is an expectation that the two components move just as smoothly what should I do? Initial thoughts are to disassemble the Y-carriage to ensure the linear bearings are oriented correctly (I am pretty sure they are). Otherwise it seems like I may need to look into getting replacement linear bearings.
Please help me out with my best options for moving forward. Let me know if there is anything I can clarify!
Thanks,
Eliot
Re: Y-axis Rough Movement
Hi Elliot,
on the Y axis your bearings are constrained by the U bolts and the Y carriage,
as the resistance seems to be positionally variable, could it be that the Y axis smooth rods are not parallel and that at one end they are wider / narrower than ideal?
the instructions call for you to use the aluminium main frame as a test to see if the chassis is the correct width, it might be worth checking this again
best wishes, Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Y-axis Rough Movement
Hi -
New user here. Just began assembling my MK2S kit, and my initial observations are very similar to Eliot's.
Briefly, I have been very meticulous with the Y carriage assembly .. I believe everything is quite square, flat, measures correctly and aligns well with the aluminum frame, and bearings are installed and tightened appropriately (not overtightened) .. things looks pretty nice. That said, I was quite surprised at how rough (and 'scratchy') bed movement is along the Y-axis rods .. certainly not very smooth at all. (I've also tried minor re-aligning a bit .. no significant change. Am I expecting too much)?
So, I'm not past step 2 yet, but am already on the Misumi and SKF sites looking for replacement bearings. Trying to improve this considerably before moving forward.
Larry
Re: Y-axis Rough Movement
The bearings can have great variations - the rods as well. 🙁
Check the bearings on the same rod by hand. You will feel - and hear - the difference. Then try other rods ...
BR
Re: Y-axis Rough Movement
Thanks for the comments on your observations @BR .. interesting. It's a subject I'm just getting into as I proceed with kit assembly. As mentioned, the roughness of the bearings along the Y-rods (even with the MK2S parts) was just unexpected and surprising (requiring more force to move the Y-carriage as @Eliot has initially noted) .. it has prompted me to research the various forum postings re: bearings, especially related to the Y-axis. I will also focus a bit more on checking out various rod/bearing combinations as you suggest. I have now placed some rods and bearings on order with MiSUMi, as well as some additional bearings with SKF, so will have a few things to check out as I move forward.
Larry
Re: Y-axis Rough Movement
Thanks for the suggesetions, I followed joan's suggestion and re-adjusted the Y-axis smooth rods. This helped the issue where I was facing increased resistance at the end of the Y-axis.
Regarding the increase amount of force needed to move the Y-carriage, I believe that is simply because it is attached to the belt and motor. I have completed my build and the amount of force needed to move the X-carriage and the Y-carriage seems pretty close now. Here is my second print: http://imgur.com/a/sSyTP
Re: Y-axis Rough Movement
I am pleased for you Eliot,
my last print of a benchy didn't go anywhere near as well as that...
regards joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK