Under extrusion? Over extrusion? Clicking? Pilling? Inconsistent layers? Clogging? Unloading problems? It's probably all the same core issue...
 

Under extrusion? Over extrusion? Clicking? Pilling? Inconsistent layers? Clogging? Unloading problems? It's probably all the same core issue...  

Page 6 / 8
  RSS
gordon.w
(@gordon-w)
Estimable Member

@ben-kindt

I wouldn't say the Mini is perfect, but I think a lot of these issues have been fixed either in design modifications (we are now on revision 4 hardware), firmware updates or improvements to the manufacturing process.

If you do have problems chatting to prusa support or asking in these forums should get you back up and running quickly.

Posted : 21/07/2020 8:14 pm
ben.kindt
(@ben-kindt)
Active Member

@gordon-w

When a hardware revision is made, are existing owners notified so they can print replacement parts, order upgraded componenents, etc.

Posted : 21/07/2020 9:39 pm
kevman
(@kevman)
Estimable Member
Posted by: @ben-kindt

@gordon-w

When a hardware revision is made, are existing owners notified so they can print replacement parts, order upgraded componenents, etc.

Yes  I need to know this as well.

Posted : 21/07/2020 9:43 pm
gordon.w
(@gordon-w)
Estimable Member

I don't believe there is any notification system. Some of the changes maybe related to ease of production rather than having any impact on users. For reference the changes so far are listed here: https://github.com/prusa3d/Original-Prusa-MINI/releases . The R1 to R2 changes were quite significant and resolved some of the issues experienced on the early production machines, but the other changes don't appear to be that major.

Edit: If you have a github account, you could 'watch' the hardware repository and get email updates when changes are made.

This post was modified 2 months ago 2 times by gordon.w
Posted : 21/07/2020 10:06 pm
malcmcm
(@malcmcm)
Trusted Member

Got the clicking again last night after fixing it last week, for me at always happened after I switch to PLA from a long PETG print. 

Here is the cold pull result. Looks like my PTFE shrank maybe ~0.1mm and that was enough for a PLA collar to form and effect the flow.

FWIW after reseating the PTFE and raising the heatbreak, no more clicking (for now). It is definitely a heatbreak/PTFE problem.

Posted : 22/07/2020 12:31 am
kelsey.harley
(@kelsey-harley)
Eminent Member

@malcmcm

If you watch the extruder motor shaft (some people put a wheel on it, I just put a black mark)  when the clicking starts, it is not feeding the filament. The filament is not coming out of the nozzle. It has to be on a layer or bed to remove the plastic from the nozzle tip. You ehave a place where there should be plastic onthe art or bedbut there isn't any. Check you Z height. setting too.

Posted : 22/07/2020 1:18 am
malcmcm
(@malcmcm)
Trusted Member

@kelsey-harley

Huh? Sorry I don't think I understand what you're implying. 

I understand the clicking is the gear skipping/not moving. My part was littered with under extrusions. But the issue is not with the extruder or the extruder gears. The problem is built up pressure and filament sticking in the hotend from the unseated PTFE tube. I've fixed it twice now by just reseating the PTFE tube, each time I have to move it up about .2-.3mm (I can confirm since my MINDA is consistent height). 

The extruder is vaguely related, issues in the hotend propagate back to point of failure, in this case it's at the extruder. Changing extruder to bondtech may help because (from what I understand) it can provide more direct force to overcome small variations in pressure down the line. Maybe someone has had issues with the extruder but in my case it's always at the hotend.

Z height is unrelated, you can still get clicking if you purge filament off the bed.

If anyone wants to test if it's the extruder or hotend, when you get consistent clicking, remove the filament. Then purge without filament or move the extruder gears. If you get clicking without filament, it's the extruder. If the clicking stops, it's the hotend (or another blockage in bowden tube somewhere).

Posted : 22/07/2020 1:49 am
vazovsky
(@vazovsky)
Eminent Member

If you go back several pages in this thread you will find that those of us who have put in the Bondtech heat break that actually works (outside diameter is smaller at the heat break zone) and that cured what you are describing.  

The Mini has an inefficient heat break (all the same outside diameter top to bottom ). The PTFE tube gets hot when you print, heat creeps up the tube and it shrinks, allowing the melted filament to sneak around the bottom of the tube and form a bulb on the end of the filament. When it cools the bulb solidifies into a blob that cannot retract back up the tube and you have a jam. Once the jam forms the extruder cannot push the blob in or out and the extruder gears grind away on the filament trying in vain to move it.  The higher temperature filament you use the faster it happens.

The Bondtech heat break is cheap compared to the frustration of constant jams. 

If you do install one, the heat characteristics of the new one are different so don’t forget to do a PID tune and put the new data in the Printer Settings>Custom G-code> Start G-code section of the Prusa slicer. It is in the Bondtech instructions. 

Posted : 22/07/2020 3:23 am
japu liked
ben.kindt
(@ben-kindt)
Active Member

A $15 upgrade cost is a no-brainer, but I'm hestitant to wheel my new Mini (once it arrives) into major surgery.  Hopefully I won't have this issue, but its nice to know there is a cure out there if I do.

Posted : 22/07/2020 4:57 am
kevman
(@kevman)
Estimable Member

For me the bondtech heatbreak did not solve the heat creep issue. 

Posted : 22/07/2020 12:56 pm
dbkay50
(@dbkay50)
Active Member

I just sent mine in for repairs. Why do we have the same problem out of the box?  Design or quality issues?

Posted : 22/07/2020 1:14 pm
Rob
 robt
(@robt)
Active Member

@vazovsky

I just installed the Bondtech heatbreak but unfortunately after 1 day of printing I'm having the same issues again. This thing is causing me so much stress. I so hope the fact that this was one form the first batch is the reason as I've got 2 more on order, think I'm just going to have to chuck this one!

Posted : 22/07/2020 1:20 pm
benji
(@benji)
Estimable Member

@robt

Just let me know what dumpster you throw it into first.

I have been printing great with my Bondtech heatbreak for many weeks now. But the problem returned once again. I have now decided to upgrade my hotend to the Mosquito which I have no doubt will eliminate the heat creep issue. However, This is not an upgrade, this is a solution to a critical problem. I should not have to resort to this, or even to the Bondtech heatbreak.

Prusa Mini Silicone Bed Leveling Mod: https://bbbenji.github.io/PMSBLM/...
Posted : 23/07/2020 9:34 am
gordon.w
(@gordon-w)
Estimable Member

@robt

Have you tried replacing any of the printed parts with the later revisions of those parts? There has to be a reason why some Mini's are a pain in the rear, and others generally behave well. If only we could identify the reason!!

Posted : 23/07/2020 3:11 pm
kevman
(@kevman)
Estimable Member
Posted by: @dbkay50

I just sent mine in for repairs. Why do we have the same problem out of the box?  Design or quality issues?

What are they going to repair? I got nowhere with Customer support...

Posted : 23/07/2020 3:23 pm
dbkay50
(@dbkay50)
Active Member

I’ll find out

Posted : 23/07/2020 3:31 pm
Classic
(@classic)
Active Member

@benji

Really? Ugh. I just recently installed the Bondtech heatbreak and so far it has been absolutely smooth sailing. However, I have no gauge on how well it will perform after a few months of printing. Having read this thread, I know you've had yours installed for a while so this is really concerning. 

I have no doubt that you tried this, but did you happen to replace the PTFE tube? If so, did this make a difference? 

On a side note, maybe by reinstalling the heatbreak with new thermal paste that would fix the problem? Over time the paste might have degraded, causing heat to creep up the heatbreak as opposed to out the heatsink? (Hopeful guessing here)

Posted : 23/07/2020 4:02 pm
benji
(@benji)
Estimable Member

@classic

I replaced the PTFE (which did shrink) and got it back up and running so I can print the mount for the Mosquito 🙂

Something worth noting: The Bondtech heatbreak  rests upon the inner ledge of the heatsink. This means that if the PTFE shrinks, you can't just loosen the set screws and push the heatbreak/hotend assembly up to compensate. 

This is something you can do with the origin heatbreak as it does not rest on that inner ledge. So you have a few mm of adjustment in the case of PTFE shrinkage. 

This post was modified 2 months ago by benji
Prusa Mini Silicone Bed Leveling Mod: https://bbbenji.github.io/PMSBLM/...
Posted : 23/07/2020 4:06 pm
Classic
(@classic)
Active Member

@benji

👍 Glad to see that you can fix it (if only temporarily) by replacing the PTFE tube. Pretty bummed like everyone else that this is still an issue.

Posted : 23/07/2020 4:29 pm
robee
(@robee)
Trusted Member

I replaced my heatbreak with a bondtech two months ago and it's still working perfectly. The only issue I have had since then was a clogged nozzle because I used a 0.4mm one for wood filament and it made a mess. I have also had issues with PETG strings getting stuck on the heatblock, slowly burning and then dropping into my print but a silicon sock fixed that (also not using PETG fixes that too!).

When I had the wood clog, I decided to measure the PTFE tube and it hadn't shrank at all. Also I suspect if it does shrink, just using one of the two that came with the Mini and cutting it to size will be a good replacement because... they can't shrink any more surely? 😂

Nearly every filament I throw at my Mini just works, but there is the odd one that I have to tweak the temperature for or flow rate.

Posted : 23/07/2020 9:27 pm
Page 6 / 8
Share:

Please Login or Register