Retracting and Clicking  

RE: Retracting and Clicking

@simonbugler.. Thats is EXACTLY the same as me...

So I am still not 100% sure if the retraction/backspin is normal.... As I see it there are 2 possibilites

1. The click is normal when it does this kind of retraction.. But the retraction should not happen (so there would be no click)

2. The Retractions are normal. But the click not.

I am swaying towards option 2... And if this is the case we just have to find out why the gears are clicking.. I wonder if there is a way to adjust the motor to allow the gears to engage better/tighter.

I may have to take the extruder off again to see.

RE: Retracting and Clicking

@jweaver

I would go with your option 2

As mine is printing ok I don't have the appetite to take it apart... just annoying click to live with.

RE: Retracting and Clicking

Posted by: @simonbugler

@jweaver

I would go with your option 2

As mine is printing ok I don't have the appetite to take it apart... just annoying click to live with.

 

 

I have to fix mine... its in a place where the noise makes it unusable

i just aked a colleague to check his and there is ZERO movement on the cog.. so i am now pretty sure that the meshing of the cog needs to be closed and i suspect there will be a way to move the motor...

RE: Retracting and Clicking

Keep us updated - I would love to fix mine too!

RE: Retracting and Clicking

Whilst on a chat with Prusa today about this, I came up with an idea of not only how to prove this is retraction (Prusa still think this is a motor fault)... But also make it better.

I notice in Slic3r that retraction on the Mini is 3.2mm and it does this at 70mm/s (its 0.8 on the mk3 which is why this is more obvious)...

I am going to slow the retractions down.. I know this will make the prints longer.. But it might stop the noise... That said, slower retractions might introduce their own problems (i.e jams) so this may not even work.

but atleast playing with the Retraction settings in Slic3r will PROVE that these fast movements are actually retractions, rather than a motor stall/fault (which Prusa think it is).

RE: Retracting and Clicking

I had the similar sound - especially when infill is gyroid - I completely disassembled the extruder, because I thought of a loose gear or something like that, but everything was screwed together as it should be. So I loosened the screw for the filament which controls the pressure to the filament (between ball-bearing and gear for filament transport - don't know the right wording) and put a small amount of graphite-grease to the bigger gear (be carful - it is very close to the filament and we don't like to have oil there !!!). This works for me and now the printer sounds as I expected it.

Best regards, Clemens

RE: Retracting and Clicking

Posted by: @jweaver

[...] I am going to slow the retractions down.. I know this will make the prints longer.. But it might stop the noise... That said, slower retractions might introduce their own problems (i.e jams) so this may not even work.

You might also try slowing down the de-retractions independent of the retractions (Printer Settings->Extruder 1->Retraction->Deretraction speed). Push too hard too fast and filament can flex in the Bowden tube, if only a bit. 

but atleast playing with the Retraction settings in Slic3r will PROVE that these fast movements are actually retractions, rather than a motor stall/fault (which Prusa think it is).

Can you fit an extruder visualizer onto the Mini extruder motor? On the Mk3, this is a great tool for seeing extruder motor movement and helps correlate noises to printer moves.

RE: Retracting and Clicking

Posted by: @bobstro

Can you fit an extruder visualizer onto the Mini extruder motor? On the Mk3, this is a great tool for seeing extruder motor movement and helps correlate noises to printer moves.

 

You mean some rotating wheel to see the motor movement?

Best regards, Clemens

RE: Retracting and Clicking

Posted by: @clemens-m

You mean some rotating wheel to see the motor movement?

Yes.

RE: Retracting and Clicking

@bobstro

You can fit it, just the motor is in the back so you won't be able to see much unless it's bigger that extruder assembly, or you turn the printer around.

RE: Retracting and Clicking

Maybe this helps: yesterday I received my new Prusa Mini. As soon as it was assembled I tried the Benchy boat that comes as an example in the USB dongle and the result was awesome: by far the best Benchy I have ever printed! It was printed in absolute silence, no clicking, just the low noise of the motors.

Then I decided to try some of my own models. Normally I use Cura for my printings, but I decided to try the Prusa Slicer. Loaded the last version on my PC, and in the initial configuration somehow managed to define a new printer instead of using the standard Mini Prusa settings: the result was an incredible noisy printing, full of clicks and clacks.

After reverting to the default Prusa mini settings the same printing was as silent as  the first one.

Maybe you are using retraction values different from the recommended and this is the cause of the clicking?

RE: Retracting and Clicking

@superkirky

How do you adjust how tightly the gears mesh together? Seems you would have to change the distance between their axes and I don't see a way to do that.

RE: Retracting and Clicking

So let me give you an update of where we are.. After a lot of complaining with Prusa via Chat, they literally gave me no help, but eventually agreed to send a new extruder..

It took 2 weeks and but it arrived and the difference was immediately clear.. Where as my original had some "slack" between the gears which was the source of the clicking.. The replacement did not.. The gears are bound tight together and there was no movement at all.

I fitted it and started a print and the improvement was immediately obvious as there was no clicking.. But the new extruder has a different and more annoying noise which happens all the time so my problems are still not solved.

Whilst I had 2 extruders I took the opportunity to take them apart and have a look inside and they look identical with no obvious differences.. However, on the old one you can clearly see the slack between the cogs..

So I tried something.. i slackened off the 2 screws that hold the motor and FORCED the cogs together and then tightened them.. And I have been able to get the slop between the cogs to stop... But its not right, as if I look at the screws, they are clearly not central and the motor does not turn as freely as it should (there is one stiff point as it rotates).

In contrast, the replacement extruder does not have the slack in the cogs.. And if I loosen the motor and then tighten again without forcing the cogs together, I still don't get the slop adn the screws remain totally central.

So I now have 3 options.

1. The original extruder with the clicking

2. The modified original extruder with the motor FORCED towards the cog, which then makes it tight

3. The new extruder which has another new/annoying noise.

My plan is to take them appeart.. Mix up the parts and then rebuild it until i can get one which is silent... The problem is that Prusa will ask for the old extruder back soon so I need to get cracking with this before they do.

So at the moment, I know what the issue is, but don't know to solve it.

If anyone wants to move the motor, you simply have to remove the extruder from the printer (2 screws).. Then crack open the extruder (4 or 5 screws)..... And then release the 2 screws holding the motor.. Push the cogs together.. And re-tightened.. In my case I had to do this hard.. Really hard.. And as I said, whilst its fixed the slack, its not introduced stiffness/resistance which can't be good on the motor or bearings.

RE: Retracting and Clicking

@jweaver

Thanks for the update! 

I’m still living with mine... it doesn’t appear to have any effect on print quality.

But is disappointing. Makes me question the quality control. And therefore the mantra of a ‘workhorse’. 

At the end of the day it’s cheap. 

Mine has also now developed a new noise on the x axis... so we will see how long it will last. 

RE: Retracting and Clicking

Hi all-

I had the same clicking *exactly* in the videos posted by folks on this thread.  Very helpful!

I debugged the extruder; which was seeming to bite into filament quite a lot.  I adjusted the spring screw; no measurable effect.  

Then I took apart the hotend, disassembled the PTFE-tube as noted here: https://help.prusa3d.com/en/article/clicking-extruder-under-extrusion-and-clogging-mini_112011

I measured the PTFE-tube in the assembly as 42.6mm... incorrect vs the documented requirement of 43.4 +/- 0.1mm.  The spare in the package is the correct length at 43.35mm, so I put that in.  re-ran the wizard (as part of this adjusts the hotend).  Clicking in the extruder is gone.

Theory: I think what was happening was extra material was getting melted into the hotend gap and the extruder couldn't back it off smoothly/properly, sometimes making a click sound due to the force needed to pull material stuck in the gap.

best,
Jeff 

BTW, I've also had watchdog errors (reformatting the USB stick and copying the files back has worked for me so far)... not 100% sure if this is a temperature thing, it does get hot.  I do plan to switch to network connections in the future... 

RE: Retracting and Clicking

I take it back; USB reformatting did not help with my watchdog issues--1 hour into my print... I will take the suggestion of others and switch USB vendors... 

RE: Retracting and Clicking

Posted by: @jweaver

So I tried something.. i slackened off the 2 screws that hold the motor and FORCED the cogs together and then tightened them.. And I have been able to get the slop between the cogs to stop... But its not right, as if I look at the screws, they are clearly not central and the motor does not turn as freely as it should (there is one stiff point as it rotates).

 

I think the stiff point means at least one of your original gears is not cylindrical, or the axle hole is offset. I suspect this is the original problem, and the factory adjusted the motor fixing with it at the stiff point, so it is a bit slack at other points.

Use the new gears, and adjust the motor fixing so the gears mesh nicely but not so tight it makes then harder to turn. Then it's back to adjusting the filament tension. Good luck!

RE: Retracting and Clicking

Posted by: @jeffery-c2

Hi all-

I had the same clicking *exactly* in the videos posted by folks on this thread.  Very helpful!

I debugged the extruder; which was seeming to bite into filament quite a lot.  I adjusted the spring screw; no measurable effect.  

Then I took apart the hotend, disassembled the PTFE-tube as noted here: https://help.prusa3d.com/en/article/clicking-extruder-under-extrusion-and-clogging-mini_112011

I measured the PTFE-tube in the assembly as 42.6mm... incorrect vs the documented requirement of 43.4 +/- 0.1mm.  The spare in the package is the correct length at 43.35mm, so I put that in.  re-ran the wizard (as part of this adjusts the hotend).  Clicking in the extruder is gone.

Theory: I think what was happening was extra material was getting melted into the hotend gap and the extruder couldn't back it off smoothly/properly, sometimes making a click sound due to the force needed to pull material stuck in the gap.

best,
Jeff 

 

Very interesting:

I had EXACTLY the same issue with EXACTLY the same details:

Had the clicking after a couple of days after receiving the MINI. I checked ... things, and found that the small PTFE tube was also 42.6 mm . I also found some filament (more colors) in that metalic tube surrounding the small PTFE tube ! So this means to me that the alignment of the heatblock was done wrong, probably, for an expected PTFE tube of 43.35mm , and not for the real one I had of 42.6mm . I cleaned everything, and at least the next 2 prints (until right now) look gorgeous ! Now I'm waiting to see if for some reasons the PTFE tube is shrinking or whatever else is happening and the issue will reappear in a couple of days, or if it was just an assembly issue and now it's fixed.

I imagine that even with a smaller PTFE tube, if you adjust correctly the heatblock, it should remain no space inside (as the documentation says: the PTFE tube should be slightly pressured) and it should work fine, but in my case it did not work fine 🙂 

Luckily that I enjoyed to open it and also see for the first time in my life how it looks like 🙂

RE: Retracting and Clicking

I missed to mention in my previous post that: not only I cleaned everything, I changed the PTFE tube with the additional one provided in the spare parts of Mini package, which had the correct dimension of 43.35 mm, and I re-aligned everything following the guides from prusa help (and having in mind that the PTFE tube needs to be slightly compressed, to avoid letting the melted materiel to get out of the tube)

PS. one of the next is when I had the issue, the other one is immediately after I cleaned & fixed the issue. I let you guess which is which :-p

PS2.: the interior of the "ugly" one was like an explosion ... I even don't know how it succeeded to remain outside in the correct shape 🙂

RISPONDI: Retracting and Clicking

Hi everyone, I have the same problem in my brand new mini. I checked everything I could, from the disassembly of the extruder to the length of the PTFE tube and screwed in all the screws according to the official guides.

Printing is fine, but this click is too annoying. I have another mini in my office and it works fine without any strange sounds.

Do you have any updates or new fix suggestions?