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First impressions - very poor quality printing.....  

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BertUK
(@bertuk)
Eminent Member
First impressions - very poor quality printing.....

Got my Mini on Friday after waiting since the 25th of October. Had read all the posts about under extrusion, heat block issues etc. but though surely, after waiting nearly 6 months Prusa would have ironed out all the issues. I came from a Trendy XY-2 3D PRO (returned after a week) and a self-built Anet A8 clone (£69 on eBay) which actually worked flawlessly with some minor modifications. I was trusting Prusa to deliver a printer that would by now be awesome and perform 'out-of-the-box'...... well, sadly now..... Heat block gaps still exists, extruder is still chewing filament, unloading filament hence a headache every time and print quality, when it works, is terrible...... Printed the nut but the top layering is very bad...... sliced a file I used on my Anet clone in Prusalicer for the Mini and it is horrible...... Now what? In normal times I would immediately return something like this....... now, I probably keep on scouring the forums hoping that the holy grail of all fixes will be out there....... 

 

Original Prusa Mini 03/20 PINDAR Misumi Bearings

Posted : 05/04/2020 9:52 am
bobc
 bobc
(@bobc)
Reputable Member
RE: First impressions - very poor quality printing.....

I think clearly there is under-extrusion, there are numerous threads on that topic.

What I am wondering is what sort of quality control Prusa are doing pre-delivery. I assume they assemble the printer, do a print test, then break down for packing. Of course that does not guarantee quality, because things can become loose in transit, or the particular test environment is not representative.

There does seem to be a quality control issue with the Mini, I have no idea what Prusa are doing to address it. Certainly if this was my product, I would be asking if we have the right quality processes in place. Sadly in most companies, customer dissatisfaction is not really measured, what is measured is money, so until warranty costs escalate or orders fall, quality issues are not given priority.

Posted : 05/04/2020 10:47 am
Joey
 Joey
(@joey-2)
Estimable Member
RE: First impressions - very poor quality printing.....

Return it.

Prusa is doing a real disservice to themselves by continuing to ship the mini as it is.

If enough people returned their minis Prusa may wake up.

Mk3 - 1X
Mk3S - 2X
2021 Hyundai Palisade
Wife - 1X

Posted : 05/04/2020 11:03 am
BertUK
(@bertuk)
Eminent Member
Topic starter answered:
RE: First impressions - very poor quality printing.....

Did some major adjustments. Widened the PTFE tubes beyond the compression olives to 2mm with a small drill bit, re-seated the heat break (calliper adjusted to the required 4.8mm), replaced grub screws with M3x6 HEX screws, reduced the tension on the copper nuts, adjusted the height of the MINDA correctly and re-adjusted the extruder idler ( https://help.prusa3d.com/en/article/clicking-extruder-under-extrusion-and-clogging-mini_112011/#_ga=2.139939376.2088955744.1585904387-983910142.1583261407)..... calibrated the first layer three times. Just printed the JP whistle and it came out a lot better. 

Yes, quality control is a big big issue Prusa!

Original Prusa Mini 03/20 PINDAR Misumi Bearings

Posted : 05/04/2020 11:31 am
bobc
 bobc
(@bobc)
Reputable Member
RE: First impressions - very poor quality printing.....

(calliper adjusted to the required 4.8mm)

Just wondering the 4.8mm spec comes from ? I think mine is less, but I guess it depends what exactly is being measured.

 

Posted : 05/04/2020 1:59 pm
BertUK
(@bertuk)
Eminent Member
Topic starter answered:
RE: First impressions - very poor quality printing.....

Note to self: to use any non Prusament PLA filament: increase temperature to 235! (The 4.8mm is spec'd in the link in my post). Look for FESTO connectors and replace all the PFTE tubing. 

Original Prusa Mini 03/20 PINDAR Misumi Bearings

Posted : 06/04/2020 8:00 am
BertUK
(@bertuk)
Eminent Member
Topic starter answered:
RE: First impressions - very poor quality printing.....

Granted! It works perfectly now! Here is what I recommend to everyone and especially NEW Mini owners: (do this even before printing anything)!

1) Remove filament

2) Set up for cold-pull - see https://help.prusa3d.com/en/article/cold-pull-mini_126399

3) Re-seat heat block

4) Set MINDA height

5) Adjust extruder intake

6) Load filament

7) Perform first layer calibration (from 0)

 

This should get you up and going without any issues!

Original Prusa Mini 03/20 PINDAR Misumi Bearings

Posted : 07/04/2020 9:58 am
bobc
 bobc
(@bobc)
Reputable Member
RE: First impressions - very poor quality printing.....
Posted by: @bertuk

Note to self: to use any non Prusament PLA filament: increase temperature to 235! (The 4.8mm is spec'd in the link in my post). Look for FESTO connectors and replace all the PFTE tubing. 

Thanks. Now I am wondering why Prusa recommend 4.8mm, but also say "further in is better". My procedure is different to theirs, I push the heatbreak as far as possible then tighten the screws (changing grubs to bolts), then insert tube, and compression fitting.

I really don't like the way the heatbreak is friction clamped with grub screws, my experience is that sort of fitting often works loose, especially when you have continuous forward/back axial loads. Might explain why their factory test passes but fails with users after extended use.

Since doing that I have had no clogging issues, I am using generic PLA with stock temp settings.

I've got some Festos, haven't tried them yet.

Posted : 07/04/2020 10:59 am
Matteo Cristini
(@matteo-cristini)
Reputable Member
RE: First impressions - very poor quality printing.....
Posted by: @bobcousins
Posted by: @bertuk

Note to self: to use any non Prusament PLA filament: increase temperature to 235! (The 4.8mm is spec'd in the link in my post). Look for FESTO connectors and replace all the PFTE tubing. 

Thanks. Now I am wondering why Prusa recommend 4.8mm, but also say "further in is better". My procedure is different to theirs, I push the heatbreak as far as possible then tighten the screws (changing grubs to bolts), then insert tube, and compression fitting.

I really don't like the way the heatbreak is friction clamped with grub screws, my experience is that sort of fitting often works loose, especially when you have continuous forward/back axial loads. Might explain why their factory test passes but fails with users after extended use.

Since doing that I have had no clogging issues, I am using generic PLA with stock temp settings.

I've got some Festos, haven't tried them yet.

Did the same here: pushed the hotend up and replaced the screws. My mini is printing wonderfully 😀

Posted : 08/04/2020 9:15 am
freeman_vincent
(@freeman_vincent)
Active Member
RE: First impressions - very poor quality printing.....

Hello, 

my first testprints with PLA were good on the Mini. But with PETG my Printer works really really bad, too. I can compare with the MK3S. The Mini is very loud and i have to stay always there while printing. 9 of 10 Prints fail. I think the MK3S works better with the direct filament support. I´ve tried a lot. The rods of my mini begin now to show marks, like on my MK3S before i changed to IGUS bearings. I can´t understand why they´re using those cheap and noisy LM8UU bearings.  I will not contact the support anymore and i won´t forget that I had to buy new rods on my MK3S after a few month (there was no support).

I´ve disconnect the filament sensor on my Mini now, beacause it´s not working. For me it´s a terrible printer in comparisson with the MK3S. I think Hotend´s with direct filament support are the only way. I don´t like the Hotend of the Mini, too. I was a Prusa Fan but now with the Mini it changed completely. For School with my students i use a Makerbot now. 

This post was modified 4 years ago by freeman_vincent
Posted : 08/04/2020 11:20 am
bobc
 bobc
(@bobc)
Reputable Member
RE: First impressions - very poor quality printing.....

So we know the cheap Chinese printers are cheap, and not as good. Then the question becomes "can one design a printer that is cheap, but still good?" The two main routes to cheapness are using low-cost manufacturers (i.e. China), or by mass-production (e.g. using injection moulds).

If you don't follow either of those, you are left with "smart design". A lot of designers think they can achieve that...in my experience they nearly always fail. The laws of physics are the same for everyone, and trying to think of something that many other bright minds have not thought of turns out to be really, really hard.

I think one has to look at the Mini for what it is. It is cheaper than MK3S. It is not as good as MK3S. That is, the Mini can still print really well when set up correctly, but only for a subset of use cases that a MK3S can handle. It seems to be a universal law; you trade quality for cost. I don't think Prusa are an exception.

Posted : 08/04/2020 12:05 pm
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