I’m having an issue where even after adjusting the concentric nut (on the relevant roller) to the peak tightness (i.e. rotate it to the appropriate point in 360 degrees), in the right hand side of the X-bar, I still seem to be unable to get the rollers to stop ‘slipping’ - and therefore the right hand side of the X-bar is not adequately keeping in sync with the left hand side of the X-bar during printing.
My understanding is that the concentric nut is to be adjusted such that the ‘slipping’ of the 3 rollers as a group is stopped - but only just - to ensure they’re not overtightened. My problem is that even at the point that the concentric nut is at it’s maximum closeness, it still does not appear to keep the right hand side of the X-Bar firm enough.
Any ideas?
Note that my problem is NOT the levelling of the X-Bar - that is fine. It’s simply that I’m unable to get the required firmness/closeness in the 3 rollers on the right hand side. Not sure how to proceed on this one. I have watched many videos on how to adjust concentric nuts, but it’s like I’ve run out of further available adjustment…
Sorry to hear your assembly is giving you problems! I recently assembled a V2 so I might be able to help. Is there any chance you could send through a photo of the front and back of the right carriage sitting on the aluminium extrusion?
Keen to see you get it assembled and start some prints!
I pulled an older printer (Ender 3, not V2) from our shelves, and found that you should have well and truly enough adjustment range to get the z-axis not only free of play, but noticeably tight on the 2040 extrusion.
Before we look into this further, where did the (what look like) metal shavings on your x-axis come from? And what caused the ring around the top nut? The wear on your innermost wheel seems to suggest it’s tight, but obviously it’s not.
Is the play just up-down? or side-side as well?
Sorry for the wall of questions, but this has really got me going!
-James
Were you referring to the rollers on the side of the printer not being close enough to keep the X-Axis stable? Or the tensioner for the belt slipping down the X-Axis and loosening your best?
If the latter:
As they’re dependant on friction against the T-Slot in your aluminium extrusions (which on the Ender 3 models are anodised so they tend to be quite smooth) pressure can realistically only take you so far to stop the slipping. Unfortunately, there are not really many available methods to improve this without modding the printer.
That being said, here’s a possible way that you can mod the printer by replacing those tensioners with custom versions you 3D print
Shout out to Jay for the article on this! His guide should be able to help you with the issues you’ve run into so far with the tensioner slipping down the X-Axis (and could maybe improve your Y-Axis too).
Hi James
If the ring you refer to is on the nut itself they look like Nylock nuts???
If it is what looks like a scratch on the paint finish this looks like a spanner or if a shifter has been used (ughhh!!!) there is usually a sharp bit under the moveable jaw which has a habit of doing this sort of thing.
Cheers Bob
I think you’re right there, Creality throw a few sheet-metal spanners into the box to help you along, but I thought I remembered the carriage that attaches to the x-axis extrusion being in one piece, hence requiring no loosening/tightening, but I might be wrong.
Thanks for your reply - in this case, the belt tensioner is working fine (i.e. I can increase or decrease the tension perfectly). Great notes thought for if/when I have any belt tensioning issues!
No worries, I was having a discussion with James about that and we were trying to work out whether it was related to the X-Axis being held steady properly by the three rollers on the vertically mounted extrusion, or whether it was the tensioner playing up and sliding down the axis.
In the case of too much play on the axis, unfortunately, there’s not much that can be done short of ensuring that the concentric nuts are at the right amount of tension as you have done already. Although one of the tricks I found when putting my ender together was to attach and adjust the rollers off of the printer, and then reattach it by pressing it back down and in (be careful that this is not so tight as to bend your frame or damage any components) and they tend to lock in quite nicely.
I know it may be a little difficult, but is there anyway that you can take a short clip of the printer running a Benchy print and upload it unlisted on YouTube, then share the link here so we can take a look at it? I’ve heard of similar issues with a few FDM printers before, although I haven’t seen it myself yet.
Thanks James, I want to answer as many questions as you have so that I can hopefully get to the bottom of this!
I’ve uploaded another two photos.
I can’t explain what does (I agree!) appear to be a metal shavings in my last photo - other than minor dust, I don’t see anything there now.
The small ring around the top nut is very much a surface scratch (no deep indent). I believe I have only used the stock spanner that came with the kit.
In the second photo (looking down), I’m wondering whether the angle of the roller being very very slightly pointed out to the left is normal?? I wouldv’e guessed that, if anything, it might be slightly to the right?
The play is purely up-down. It appears to fit pretty snugly (in all respects other than up-down) and I wouldn’t ask the question except for the few mm up-down play being enough that I notice when turning the z-screw up or down, there’s enough lag to notice the right side is not keeping up with the left side of the X-bar. E.g. from when the nozzle is on the bed, I raise the X-bar but I can just notice the right side lagging behind the left side. The only other symptom I can see is that (as per my original query) I can’t quite tighten the concentric nut to a point where the rollers don’t ‘slip’.
I don’t think I’m understanding how the tensioner may be sliding down the axis (just to eliminate this as a source of the problem) - but I don’t believe this is the problem.
In terms of the rollers, the two (of the three) on the right hand side are in place, but they are just not tight (they spin in place relatively easily). And although I don’t get a huge amount of difference in up/down movement on the left vs the right sides of the X-bar, I just feel that if they are supposed to - and I can achieve it - if the concentric nut can be adjusted a bit further it might solve the problem.
Anyway, I’ll look to send a link of a clip on Youtube - might be a few days by the time I record and get it successfully shared to you.
While it’s a little hard to see from the photo, that slight lean you were talking about might be the culprit! Is there any chance you feel like taking apart your x-axis and tightening the bolt (or whatever it is) on the other side of the plate to the concentric nut? If you can’t get it tight after that, I’ll examine my V2 at home and if your play is still unreasonable it might be a faulty unit.
It’d also be fantastic if you could upload a video of the play/lag you’re talking about so other owners of this machine can pipe up with their thoughts!
-James
Hi Geoff, James
I am not too familiar with 3D printers but just had a look at some videos re modifications etc. It seems that this printer Xaxis assembly is only lifted from one side. This seems to me to be a bit of a weakness. Without the assembly being super precision and super smooth in operation I don’t see how you cannot have some lag. A bit of slack design really. I don’t see it being too difficult at the design stage to have a screw drive on both sides being driven by a toothed belt to keep both sides in step. Probably a bit hard to retrofit but may be worth looking at. If another screw drive can be fitted it could maybe even be driven at the top. Just a thought.
Cheers Bob
Probably a bit hard to retrofit but may be worth looking at
Funny you should say that, in that the Creality CR-10S (an upmarket version of this printer from the same manufacturer) features this by standard:
What I will say though is that the cantilevered z-axis on my Ender 3 V2 has been plenty tight in the year+ I’ve been hammering out prints on it, so I think Geoff’s printer may be a bit of an outlier.
Hi James
That suggests to me they know there could be a problem with some printers. From your experience not encountered by all. That is the sort of thing I would be looking at re drive to all axes if I were choosing one of these devices. That may just me being fussy.
Cheers Bob
I agree completely there, the Ender 3 V2 is kinda placed in the market as the bare minimum for consistently decent prints once set up, and another Z-Motor and driver would likely push the cost over the barrier of entry for a lot of people. In all honesty, if you just want decent PLA prints, then an Ender 3 can’t be beat for value and community support/upgrades, but of course there is an ocean of significantly more expensive, slightly better printers (one of which I’m building myself, watch this space).
Hi James
Basically right, like a lot of things these days they have to build to a price to be competitive. It may be possible to modify the Ender 3 if suitable parts were available. You would not need nor would it be advisable to have an extra motor. Just drive the extra screw feed from the existing one. The existing motor may have to be beefed up but again it may have enough grunt in reserve to cater for the extra screw. It still has to lift the same weight.
Keep us posted on your home grown unit. Interested. May not be such a huge project as I think all the rails, guides and feed mechanisms are available. Some of the nicer feed systems can be a bit exy though.
Cheers Bob
If you have run out of adjustment on the right-hand concentric the likely reason is that the left hand wheel bracket is poorly aligned. If the x-axis bar is not perpendicular to the left hand upright then no amount of fiddling with the right-hand adjustment will keep the right-hand bracket hard up against its upright. I would loosen off the right hand adjustment and adjust the left hand side so that the right-hand side is nearly correct with the eccentric near the middle of its range. Then tighten everything. This may require re-levelling the bed.
Before starting, confirm that the two uprights are exactly parallel, although I can’t think of any reason why they wouldn’t be. But if they aren’t for some reason then the x-axis bar will move with height changes no matter how carefully you set the rollers.
If your model was not supplied with a top bearing mount for the z-axis screw, go to Thingiverse and print one. It probably has no direct effect on your current problem, but if the screw is not aligned properly strange things can happen as the print height changes.
