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

Purging Filament

Thanks for this tip on the purging filament!  Looks like my local shop has some.  Do you think this should do the trick?  https://www.microcenter.com/product/504713/advanced-engineered-filaments-purge-filament-175-mm

Filament Type / Brand

In my case, since I have a new machine, I am pretty confident in saying that my problem stems from the filament I purchased to use in the Mini.  I don't think it's of the highest quality, especially when I compare it to the sample prusament filament that came with my printer, which I have not had any problems with.  My friend uses Hatchbox filament with his Prusa with success.  So I think that's the route I'm going to go now. 

Slice engineering fixed it for me

A couple of thoughts on this, which can be common across many printer manufacturers.

I had constant issues with extrusion, not soo much jamming but uneven layers, missed steps. I tried the bondtech heartbreak, no difference, tried the bondtech extruder, no difference, checked belts and even took apart and re-assembled, re-seated the hot end no difference. What did for me was installing a slice engineering hot end.

Not one blockage or extrusion issue since. Now it’s one of the best small printers I have and had been going strong for months. 

It was an expensive fix though which shouldn’t have been needed. In my 8 years of printing and many printers owned I’ve come to realise its sometimes the luck of the draw, no matter which manufacturer or cost of the printer.

Quality control in parts, tolerances and assembly, design flaws and even shipping all play a part, 3D printers will never be 100% plug and play with no issues . Some manufacturers may have a higher rate of printers with issues, some will be better however just because you pay more or go with a certain brand doesn’t mean you won’t be stuck with issues, it’s just how it is due to the nature of the machines.

I guess when there is not much between brands in terms of reliability it all comes down to customer support, which in itself is tricky, they have to assume zero knowledge of the user, ensure they’re not doing something daft and are clearly following their instructions, correctly applying any fixes or tuning, all remotely which is a slow process and has its limitations.

There are many reasons why the printer could not be performing as expected, sometimes the issue could even just be a bad batch of filament so you can understand why support need to go through quite a few scenarios before even considering an expensive return/replace.

I have used Prusa support who were really good at identifying an issue with first layer height caused by the probe not being temperature aware with the fix being a preheat however for the extrusion issue which was sometimes intermittent I knew it would be quicker to just throw money at it to fix it.

I could afford this and was happy to get it working with a better hotend but do realise not many would be comfortable with the install or with shelling out more money.

For those people while unfortunate I would expect lengthy support sessions and if no user fix is found I would expect a refund or return/replace by Prusa. I don’t have experience of this with Prusa other than around some known defects (lcd replace) however for general users this should be an important aspect before purchasing a printer.

Another simple trick that worked for me

In the midst of all this detailed and technical analysis that everyone is providing (thank you, btw), I would also like to add, in my case, I found that the filament I was purchasing (being sold as 1.75mm) was actually 1.5mm when I measured it with my digital calipers.  I then proceeded to select the Generic PLA profile in the Prusa slicer software and change the filament width to 1.5mm.  This improved my experience immensely.  That is why my filament felt so much different than the sample prusament that was bundled with my printer.  Since changing this setting I have been very successful in my printing efforts with the Prusa Mini!  I hope this helps others as well!

hmm... that could mess with your print quality...   and hilights that we should check filament dimensions and not assume that they a re correct...
good catch. 
did the reduced diameter of the filament give noticeable 'slop' in the bowden feed? did it mess with your retractions?
regards Joan

Back to square one...

Well, I spoke too soon.  I had a lot of problems tonight printing with the sub-par filament.  I think I'll be taking it back to the store where I bought it from and go another route.  I have some Hatchbox filament off of Amazon ordered which will be here tomorrow.  The problem with the sub-par filament is that it is somehow stopping up the nozzle (see attached photo).  After only a few minutes of printing, I hear a click, click, click and that's when I know it's gone wrong.  It's obvious the quality of the Prusament filament is very good, especially when I hold the two side-by-side.  I don't know, perhaps it's some sort of calibration or flow setting that I'm missing, but the fact that the 1.75mm filament is only measuring at 1.5mm is obviously troubling to begin with.  I will continued to keep this thread posted with my efforts.

RE: Seen this before

That's a clear sign of the PTFE not sitting flush with the end of the heatbreak. Filament had a chance to leak in-between and clog it up. 

Follow this guide to hopefully resolve your problems: https://help.prusa3d.com/en/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449/

Thank you!

Thanks so much, Benji!  I'll give that guide a Go!  I appreciate your help!

Purge Filament

I have never tried that one, but I have had good success with eSun and Novamaker.  I am really not sure if it works as a solvent or just pushes our the plastic.  I load it and let it sit to disolve for abotu 60 seconds and then purge a little.  I do that 3-4 times and then load the orginal filament.  It works most of the time.  

Posted by: @dennis-st-john

Thanks for this tip on the purging filament!  Looks like my local shop has some.  Do you think this should do the trick?  https://www.microcenter.com/product/504713/advanced-engineered-filaments-purge-filament-175-mm

Recent fix that worked for me

I was struggling with some very cheap red filament on sale at Amazon for like £10.50, after having a lot of success with other very cheap filaments, and finally tuned it to work at a high temperature with low retractions so it was useable. Then I switched to a better quality filament and my benchys (5 of them with setting tweaks to fix this) were failing on the struts as the bow neared completion. So I tried something I had been meaning to try for a while, which may help other people as it seemed to work (caveat at the end!):

1. Unload the filament
2. Disconnect the PTFE tube from the hotend side
3. Remove the PTFE tube from the heatbreak
4. Heat the nozzle to 250
5. Push cleaning filament through the hotend until it runs clean
6. Use a needle to make sure the nozzle isn't clogged
7. Let the hotend cool down completely
8. Put something over your heatbed so it doesn't get splashes anywhere (you can clean them with isopropyl but its a pain!)
9. Spray WD-40 Specialist Dry PTFE Lubricant (or equivalent PTFE lubricant that is temperature safe to 250C+) into the top of the heatbreak (you can be a little generous here)
10. Let it dry
11. Make sure your area is well ventilated (I have no idea if the fumes from PTFE are bad)
12. Heat the nozzle up to 290C so any excess PTFE lubricant burns off (it really will bubble)
13. Let the hotend cool again
14. Reinsert the PTFE tube into the heatbreak
15. Re-attach the PTFE tube to the extruder

This is before and after with identical Gcode:

Important Caveat:

I have printed a bunch of things perfectly since I've done this, but I am not sure if using the cleaning filament fixed things or the PTFE lubrication helped reduce friction at some key point in the heatbreak.

Quality of Filament

Thank you very much for your input and experiences Robee!  Everything you say makes sense.  I am returning the cheap filament to my local store today and will give the Hatchbox filament I ordered at some point this weekend.  I truly believe the filament dimension really plays a huge role here.  If you can be using filament that measures as close to 1.75mm as possible, such as the expensive Prusament filament, then I believe you will have a better experience.  Of course, all of these other tips and tricks are very useful information as well.  At the end of the day, it is crucial to know your machine (how to take it apart, maintain it, clean it, etc.).  I have no doubt this is a great machine, I just have yet to see it, except for when I used the included sample filament (Prusament) bundled with my new printer, which I received less than a week ago.  Really looking forward to getting this thing up and running!

My issues have been resolved!

I would like to update this thread and re-iterate my perception & experience that quality of filament matters when using this machine - the Prusa Mini.  Since receiving my new filament (I purchased several spools of Hatchbox brand filament from Amazon), I have had ZERO issues and several successful prints.  Furthermore, it is the tolerance to spec (1.75mm) that I believe matters most.  Hatchbox touts a dimensional accuracy / tolerance of +/- 0.03mm when using their filament.  The brand I tried using before (Inland) was WAY out 0f spec.  My digital calipers measured their brand at 1.5mm, nowhere near the 1.75mm needed to support printing with the Prusa Mini.  Attached was my first print after switching filament brands.  Enjoy and Happy Printing!

RE: Bondtech heatbreak

I've added the bondtech heatbreak and haven't had the issue since. I'm not optimistic however. Been a week so far.

What brand?

Posted by: @dennis-st-john

I would like to update this thread and re-iterate my perception & experience that quality of filament matters when using this machine - the Prusa Mini.  Since receiving my new filament (I purchased several spools of Hatchbox brand filament from Amazon), I have had ZERO issues and several successful prints.  Furthermore, it is the tolerance to spec (1.75mm) that I believe matters most.  Hatchbox touts a dimensional accuracy / tolerance of +/- 0.03mm when using their filament.  The brand I tried using before (Inland) was WAY out 0f spec.  My digital calipers measured their brand at 1.5mm, nowhere near the 1.75mm needed to support printing with the Prusa Mini.  Attached was my first print after switching filament brands.  Enjoy and Happy Printing!

 20211001_215958.jpg

What brand were you using?

It was the Inland Brand

The brand I was using was Inland brand which is sold by Micro Center (my local electronics store).  In my opinion, the quality control at the Inland manufacturing facility leaves much to be desired.  It is a much cheaper brand overall, so, as they say, which I should know by now, "you get what you pay for".

Inland

I've heard nothing but horrible things about Inland.

I concur!

Well I can definitely attest.  It is horrible!  I purchased about 7 spools, opened 3 or 4 and had major problems with them all.  Finally, I measured the filament with my digital calipers and the filament diameter came out to 1.5mm.... THAT's horrible when it's being sold as 1.75mm.  No wonder all the problems with Inland!

Hmm

I love their PLA+.  The natural color is one of my favorites.  I have had no issues on my Mk3S.  I have not tired in on my minis.