I am a true Prusa-fangirl. When someone asks what kind of fdm printer they should get my advice will always be 1. a prusa and 2. please look online for as much advice as possible because I love Prusa but I know other people are very happy with their printers that may or may not be Prusa’s.
We got out first 3d printer about 5 years ago now, a Prusa MK3s+. It was a kit, my favorite soul-mate weirdo started assembly in the late afternoon and when I woke up the next morning he was just done, and had not had any sleep. But we could print! It is magic! But that is not the topic for this story.
About two (and a half-ish?) year ago I got a Prusa Mini+ (assembled) from my mom, because I had done some house-sitting and cat-feeding during her 1 week vacation. I was over the moon! Our Prusa Medium (the mk3s+) is a true workhorse, and I will admit we had our fair share of issues and parts-replacements with it, it is just a reliable machine in general.
My Prusa Mini (I stopped typing and saying the +, too much effort) on the other hand, has been a pain in the behind from the start. Well, the first couple of weeks it printed fine, and then the layer shifts started. It took some time to figure out what caused that. A very observant person on the Prusa forum replied on a picture I posted there was a line on one of the rods, and indeed there was damage due to some part being assembled wrong. I got the printer assembled, so it wasn’t me, and I got the new parts from the company after contacting the help-folks.
After replacing the parts is was just nasty, some prints were fine, others were a horrorshow of underextrusion, overextrusion, layer lines shouting out of the print, and so on. I have squared the stupid thing so many times, did the calibration again, I replaced the heatbreak with a bondtech (that fixed some extrusion issues), and was about to throw the damn thing in the river. In a last effort I got it apart to the point where I might as well had gotten the kit and found some bolts in the inner working that should be tight, but were very much not.
LO AND BEHOLD: that fixed most of the print-issues!
So next up: the first layer issues.
Now, the first layer is the layer that goes directly onto the plate (no sh*t Sherlock), and up to this point I had not given that much attention because I had bigger issues. Those were solved, this was next.
After a round of more squaring (really, I can almost do this without the tutorial and with my eyes closed) it appeared to be okay, but also not. The left-half of the plate had a perfect 1st layer, and the right-half was a mess and the nozzle should be closer to the plate. But a problem like this does not make sense with a Prusa; before each print the machine will calibrate the plate-height by itself, and the distance between nozzle and plate should be consistent all over. Except it was not.
By now I was very much done with it, I decided to print some small things on the left-side of the plate and look back once I had the energy, brainspace and my frustration would have disappeared.
So, about a month ago I got a Prusa MK4 with MMU. The MMU has a steep delivery time, hopefully it will arrive next month, but I got the MK4 as a kit. I still have a small trauma because of the Mini’s assembly faults, and I wanted to learn how the printer works and fits together so I can deal with issues should they pop up. I took my time, about a week, to assemble the thing. When it was done, the prints were pristine, smooth, the details are amazing and the quality out-of-the-box-after-assembly is the same as with our mk3 with all it’s tweaks. I felt so proud and happy, I did this all by myself and I got confidence that my struggles with the mini are not because I am dumb.
So, today I had a day off, and I scraped my courage together and started on the Mini.
First thing: update the firmware!
My thought was that the machine is squared, I did that very diligently last time.
Each print has a calibration-stage, and still the nozzle-bed distance is not consistent.
This could be a firmware issue, and my Mini ran on 4.3.1, and the current version was 5.something some weeks ago. I did try to update it then, but the stupid little printer refused to accept the update files on the USB stick. I had done the things the Prusa tutorials told me: formatted all my usb sticks, I formatted 2 sd things and tried them with a usb converter, and I cursed a lot (this was not in the tutorials) but kept failing successfully, which is why I never upgraded. But now I was determined, if other people could update the thing, so could I!
I did so much searching but I found the solution scattered over several forum-posts and some reddit threads.
By now my mini was still on 4.3.1 and I needed to go to 6.6.0 (the current version).
The steps I had to take are:
downgrade my mini to 4.3.0
- downgrade my mini to 4.3.0
- then upgrade to 4.3.1
- then upgrade to 4.3.2
- after this I upgraded to 4.3.4
- I got the 4.4.0 firmware, but I put only mini_release_boot_update_pre_4.4_4.4.0+4180.bbf on the usb stick, and flashed that on the mini
- when it had done this the mini screen said ‘waiting for BBF’, I added the mini_release_boot_4.4.0+4180.bbf file to it
- stuck it back in the mini, and the update to 4.4.0 will continued, and that worked!
- next I upgraded the mini to 4.4.1
- after that 5.1.0 (all the languages), and upwards
I did not dare to go from 5.1.0 to 6.0.0, I took al the little steps but that did not take up as much time as the whole circus I had to go through before this last part.
My prusa mini is now on firmware 6.6.0, I did all the self-diagnostic tests, did the first layer calibration… and it looked like… well not what I hoped for at all.
So, back to google!
I discovered that more people have issues with the Prusa Mini with Bondtech heatbreak when using PLA filament. Fortunately I found this post pretty fast, and I just tried these settings, along with the lower temperature I was already working with.
My first 2 test prints just now (after a bit more 1st layer fixing) look fine, my Mini made a benchy after those and the quality was all that I hoped for; smooth printing, no layer lines sticking out, no extrusion blobs. Again, I am very proud, but still cautious. Over the next few days I am going to print a lot of things on that mini, all kinds of shapes, sizes and make it work so I can hopefully learn to trust it again.