Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Took delivery of new Mini - assembled and all initial test completed without issue.
Created gcode under Prusa slicer for 27 No. clips which I've been printing all year without issue (in 30 item print batches) on an Anycubic s3 (produced using Cura slicer).
First job started off well after 1st layer calibration had been completed. As a 20hr job, I left it to run overnight, and a check before I left for the day circa 5hrs into the print job - no issues evident, all appeared to be going perfectly.
Arrived this morning to fine the job only printed to a height of around 10mm (OA height of completed is 28mm). The LCD screeen said the job was 100% completed in 19h 15m, but this was clearly not the case.
The filament had broken after the extruder gearing and the printer failed to detect this (How? filament would not be 'moving' through the sensor, so it should halt the job yes?).
I had to detach the boden between the hot-end and the extruder to clear broken filament, before I tried another (smaller) print job.
Since this issue with the initial print, I have NOT been able to print.
Filament load/unload is okay. When purging after filament loading, it is no longer apparently feeding filament.
I get a small amount leak from the nozzle due to heating, and then it stops. Cannot complete a first layer test, cannot print - no filament output at all.
I have performed a cold-pull in line with guidance on this site. No change.
I can hand-feed filament directly into the hot-end at 275C and this runs through fine without any issue or discolouration. All signs point to no issue at the hot-end/nozzle.
The gearing for filament pull seems to be suspect though.
If tension is too high, then the extruder gearing will deform the PLA and break it at some point. If too low, then it just clicks incessantly.
I cannot find a point on the extruder tensioning that works reliably (I think this is where the problem starts with this unit).
I'm servicing a low volume production of PLA printed clips from 3D printers, and the intention was that Prusa would step into the fray as AnyCubic's will suffer issues after about 6 months of use (gone through 2 during 2020, although 2nd is still serviceable - common fault is cooling fan failure in the PSU situated in the printer's base).
I am extremely disappointed in Prusa Mini we've received and have spent close to 6hrs today trying to resolve the Prusa issues, with no success whatsoever.
Any help or guidance from the manufacturer's own support personnel would be greatly appreciated. This unit will be returned for a full refund, if this cannot be swiftly resolved.
As it stands, this unit is unusable and appears to be riddled with design flaws in the extruder gear and filament sensing.
HELP!
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
PS: Has any other Prusa Mini owner noticed the following odd behaviour?
If the bed or X-axis is moved while the printer is turned OFF, current is induced by the action of unpowered motors which then makes the LCD screen flash?
I noticed this during assembly, and would like to add this as a minor concern here.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
We received our new Mini in November, it printed perfectly several times then during one PLA print it stopped extruding material part way through. After unclogging it and extracting the filament, we were able to purge new filament just fine and print the first layer of any build almost perfectly, but then when the speed of the build picks up after the first layer it only dribbles out material. We've done the cold pull too, and cleaned the extruder, but the problem still is there. Multiple different filaments, multiple parts including the included test files, perfect purging and first layer, and then very poor quality after. Very disappointing.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
PS: Has any other Prusa Mini owner noticed the following odd behaviour?
If the bed or X-axis is moved while the printer is turned OFF, current is induced by the action of unpowered motors which then makes the LCD screen flash?
I noticed this during assembly, and would like to add this as a minor concern here.
I never noticed this, but yes mine does it too if you move fast enough.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
PS: Has any other Prusa Mini owner noticed the following odd behaviour?
If the bed or X-axis is moved while the printer is turned OFF, current is induced by the action of unpowered motors which then makes the LCD screen flash?
I noticed this during assembly, and would like to add this as a minor concern here.
I never noticed this, but yes mine does it too if you move fast enough.
FWIW - The Mk3 does the same.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
DC motors act as generators when you apply input power to the axle.
It is not advised to deliberately produce this effect as it is possible to damage the board - if moved fast enough the induced voltages can be quite high.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Took delivery of new Mini - assembled and all initial test completed without issue.
Created gcode under Prusa slicer for 27 No. clips which I've been printing all year without issue (in 30 item print batches) on an Anycubic s3 (produced using Cura slicer).
First job started off well after 1st layer calibration had been completed. As a 20hr job, I left it to run overnight, and a check before I left for the day circa 5hrs into the print job - no issues evident, all appeared to be going perfectly.
Arrived this morning to fine the job only printed to a height of around 10mm (OA height of completed is 28mm). The LCD screeen said the job was 100% completed in 19h 15m, but this was clearly not the case.
The filament had broken after the extruder gearing and the printer failed to detect this (How? filament would not be 'moving' through the sensor, so it should halt the job yes?).
I had to detach the boden between the hot-end and the extruder to clear broken filament, before I tried another (smaller) print job.
Since this issue with the initial print, I have NOT been able to print.
Filament load/unload is okay. When purging after filament loading, it is no longer apparently feeding filament.
I get a small amount leak from the nozzle due to heating, and then it stops. Cannot complete a first layer test, cannot print - no filament output at all.
I have performed a cold-pull in line with guidance on this site. No change.
I can hand-feed filament directly into the hot-end at 275C and this runs through fine without any issue or discolouration. All signs point to no issue at the hot-end/nozzle.
The gearing for filament pull seems to be suspect though.
If tension is too high, then the extruder gearing will deform the PLA and break it at some point. If too low, then it just clicks incessantly.
I cannot find a point on the extruder tensioning that works reliably (I think this is where the problem starts with this unit).
I'm servicing a low volume production of PLA printed clips from 3D printers, and the intention was that Prusa would step into the fray as AnyCubic's will suffer issues after about 6 months of use (gone through 2 during 2020, although 2nd is still serviceable - common fault is cooling fan failure in the PSU situated in the printer's base).
I am extremely disappointed in Prusa Mini we've received and have spent close to 6hrs today trying to resolve the Prusa issues, with no success whatsoever.
Any help or guidance from the manufacturer's own support personnel would be greatly appreciated. This unit will be returned for a full refund, if this cannot be swiftly resolved.
As it stands, this unit is unusable and appears to be riddled with design flaws in the extruder gear and filament sensing.
HELP!
So much for 'support'.
Is this the correct place to log issues with new printers? No response from any PRUSA personnel here and the community response has been underwhelming so far, to say the least.
What is wrong with this brand new printer and is it actually possible to resolve?
PLA can be manually fed through during the steps leading into a cold pull.
No discolouration or debris evident when doing so.
PLA will not feed through when 'driven' by the extruder.
Driven extruder either destroys PLA leading to upstream breakage (tensioner too tight), or fail to feed completely (tensioner backed off, even a little at a time).
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
It's probably still clogged in a way. Work through all of this if cold pull is not enough. Also, if you want to get in touch with official support the forum is apparently not the way. Go to the shop, use the live chat popup in the bottom right corner (might not appear in firefox for some reason).
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Is this the correct place to log issues with new printers? No response from any PRUSA personnel here and the community response has been underwhelming so far, to say the least.
What is wrong with this brand new printer and is it actually possible to resolve?
Bluntly put: no, this is not the place to log issues - if you need Prusa support, contact them directly through either the live chat or the contact form.
That being said, I had similar issues with my Mini+. (fter about 2 weeks of printing without problems)
For me, the solution was to clean all debris from the extruder (with a toothpick) and to replace the hotend PTFE tube with the spare one that's included. Might be worth a shot.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Having tried everything, we finally tried the procedure for replacing the hotend PTFE tube, and it worked! I think it's worth noting that the factory-installed tube was 1 mm shorter than the spare tube we installed. The spare tube measured almost exactly 43.4mm as it should be according to the guides. Of course, now how long will this fix these issues? Hopefully for good.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Have you got any more spares?
Do you need to get the materials to make more spares?
https://help.prusa3d.com/en/guide/how-to-trim-ptfe-tube-original-prusa-printers_22424
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: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
@joantabb
No we don't have any other spares. Will look into this so we can produce our own if necessary. Thank you.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Is this the correct place to log issues with new printers? No response from any PRUSA personnel here and the community response has been underwhelming so far, to say the least.
What is wrong with this brand new printer and is it actually possible to resolve?
Bluntly put: no, this is not the place to log issues - if you need Prusa support, contact them directly through either the live chat or the contact form.
That being said, I had similar issues with my Mini+. (fter about 2 weeks of printing without problems)
For me, the solution was to clean all debris from the extruder (with a toothpick) and to replace the hotend PTFE tube with the spare one that's included. Might be worth a shot.
Thanks for your reply and useful direction. I had wondered why the 'Support' page offered no link to manufacturer support - Prusa should consider consolidating support links to render them all accessible from the Prusa support page.
I am going to disassemble the hot-end next week to give it a thorough check, although I have no reason to believe there is debris in the hot-end having performed a couple of cold pulls and only actually had around 8 hrs of print activity, before the first job halted leading to this issue.
From responses thus far, and what I can see with the printer itself I am now inclined to look more closely at the hot-end's short section of internal Bowden tube. The collars at either end are likely to cause 'splaying' of the tube end sections, as everything is tightened down which may reduce the clearance diameter, thus blocking the filament path.
Will take a look at this next week, and I will update this thread (hopefully to close the issued as resolved!).
If no improvement, then I will pick it up with LiveChat following - thanks.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
@nginear
"if you need Prusa support, contact them directly through either the live chat or the contact form." Chat is the preferred method of optioning support.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Reading all this I'm beginning to think I should cancel my order for the Mini+, its not shipping until Feb.
I waited until the revised mini and I thought the Mini+ was now a good time to jump in.
Its making me nervous as this I hope this would be a big step up in hardware and print quality over my Monoprice that has been printing like a champ for 12 months printing every few days, so far I have had no issues. All I needed to do is grease the moving parts. Never had any jams
I reading so many people having issues with tube issues. I know they are backlogged at Prusa but you would think they would check the assembly as so many report issues with this part.
This Mini+ is a big investment for me over the Monoprice, gettimg the Prusa to Canada makes it around 3 times the price I paid for my Monoprice
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Prusa Mini+ (Ordered Dec 19,2020 - Arrived Feb 21,2021) stated clicking Mar 2nd / MP Select Mini V2
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Reading all this I'm beginning to think I should cancel my order for the Mini+, its not shipping until Feb.
I waited until the revised mini and I thought the Mini+ was now a good time to jump in.
Its making me nervous as this I hope this would be a big step up in hardware and print quality over my Monoprice that has been printing like a champ for 12 months printing every few days, so far I have had no issues. All I needed to do is grease the moving parts. Never had any jams
I reading so many people having issues with tube issues. I know they are backlogged at Prusa but you would think they would check the assembly as so many report issues with this part.
This Mini+ is a big investment for me over the Monoprice, gettimg the Prusa to Canada makes it around 3 times the price I paid for my Monoprice
YMMV but based on my experience, I would not be recommending the Mini at present and especially if returns are likely to be cost-prohibitive, in the event that the unit does not meet expectations (ie Not fit for purpose).
I spent over 2 hrs with Livechat - very helpful, but ultimately unable to resolve the issue.
I've now got a few weeks (60 days from date of delivery) to either resolve the issue myself or arrange a return with shipping at our cost.
I have replaced the PTFE liner to the hot-end. The factory installed tube was 42.5mm and the spare was 43.5mm per KB's and recommended length. I changed to the spare, but this has made no difference.
My current position is that the design is flawed, something I have offered in today's Livechat.
The brass coupler arrangement at the top of the heatsink has an aperture which will not tolerate any deforming of the filament as the extruder gear drives it through. And that seems to be where most of the issues stem from.
Extruder tensioning seems to be quite binary. If it's clacking, it's slipping and this damages the filament to a lesser extent (shaving).
If it's not, then its either feeding fine (something I have not seen yet) or it's compressing and deforming the filament slightly out of circular section, leading to blockages at the brass coupling's through aperture (which screws into the top of the heatsink).
I still have some hair left to pull out, so I'll get back to looking at this little monster until I'm completely bald.
Will likely be updating the thread with news of return/refund being requested in the coming weeks, although I actually hope not. As it stands, I don't see how I avoid this with the issues faced and multiple potential remedies, none of which have been helpful in resolving.
I have committed with Livechat to take a closer look at the extruder gearing condition. However, if a total of 5hrs of print activity is enough to upset the extruder gears, then I cannot consider the unit as anything other than unfit for purpose.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
I too have had a monoprice printer for years and never had a single feed issue. I was excited to get the Mini for accuracy, fine quality, improved interface, and easy part removal. Outside of this feed issue, the Mini has lived up to all of those expectations, but it was incredibly frustrating to spend so many hours fixing something without a lot of help or even reason for the issue in the first place. If you can wait, perhaps it's worth holding off until there is a factory fix or a published quality improvement. The replacement with proper length PTFE hot-end tube did fix our issue, but who knows for how long. I definitely don't trust the machine right now, so that might be a reason to wait too.
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
Ok, so a small update;
1./ Extruder gearing taken apart and inspected and all looks well. There are no larger pieces of debris - just a little dusted filament.
2./ Hot end taken apart and nozzle removed and it looks like there is a cooling issue which is causing filament to accumulate at the junction between the nozzle and the chamber above which takes the PTFE liner.
Currently soaking both parts in acetone to try and soften this hardened/baked PLA.
Once cleared, I am going to go through calibration and try to get some output from it.
Is this model still suffering cooling issues?
This looks like excessive cooling draft above the hot-end!
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
I had all the same issues, but ultimately it was what seems to be a common issue with the heat-break and PTFE. The PTFE shrinks, causes clogs, you can clean it all out (cold pulls) then move the heat block up to take up the slack, or replace the PTFE. What I opted for was the Bondtech heat-break which is supposed to minimize this issue. I just installed it yesterday, but so far so good. Printer is back to printing great.
https://www.bondtech.se/en/product/bondtech-heat-break-for-prusa-mini/
RE: Mini (New: Shipped Dec 16 2020) - PLA feed & printing issues
@prolix21
This seems to explain the 42.5mm measured on the installed tube, versus 43.5 manufacturer's spec. and supplied spare.
I've got the nozzle and heat-break cleared, but am now dubious about reassembly and trying to print again without addressing the actual underlying cause, as I don't want to be taking the hot end apart on a weekly or worse basis.
For the relatively low cost of the Bondtech replacement, this is worth trying so I will look into ordering and hope they can deliver before my 60 day window for Prusa's return closes.
Looking at the problems though, this does like it will address the cause, so you have my appreciation for bringing this to one frustrated user's attention - I suspect more may appreciate awareness of this solution!
PRUSA: Why are you not incorporating this $15 part as standard on the Mini? Your own design improvements between those shipped at the beginning of the year and mine in December have been an abject failure to the casual observer and this disappointed 1st-time Prusa purchaser.