Always unwanted filament on noozle & sheet
The Mk3x start procedure was perfect. No filament on the noozle at print start, nothing at the end.
Our MK4 produces a lot of filament crumbs on the sheet, during Z adjustment and s.c. noozle cleaning.
And on every print there's a 10-20mm filament string left at end of print on the noozle.
Now all that unwanted stuff must be removed after every print.
It seems that the MK4 has the filament flow BEFORE and AFTER the print not under control.
Filament runs out as the extruder heats up...I used only prusament for that mashine since arrival.
Does somebody tried to "convert" the MK3Sx start gcode to MK4?
To remove that, in my eyes, nonsens "noozle cleaning /touching the sheet" to get a nice purge line.
RE: Always unwanted filament on noozle & sheet
Welcome to the club. Same here.
RE:
Mk3S or + w/MMU2 does not touch the sheet during Z calibration, and that's why there are no crumbs.
Yes, the MK4 Loadcell sensor is a good thing, but before tap the points on the sheet please let the extruder turn a little backwards in next HW Update. I think this would be a solution. 1-2 mm is enough and there will be no crumbs.
This crumbs are hard to remove, the noozle presses small filament dots on the sheet -> you have to abrade them, get scratches on the sheet, this crumbs fall onto the heat bed and so on...
RE: Always unwanted filament on noozle & sheet
I would also like to see a customized launch code. On my MK3S+ with special startcode the nozzle is first heated to 160C, then the bed is leveled and the nozzle is homed. Then the bed is fully heated. The nozzle is still at 160C and is not heated to extruder temperature until just before printing. This is perfect.
With the MK4, the nozzle is first heated to extruder temperature, then leveled and cleaned, and only then lowered to 160C until the bed is heated. During leveling and cleaning, however, the entire bed is already full of filament pieces. Nobody needs that!
I have unfortunately no idea of gcode programming, but if someone could adjust the start code in this direction I would be thankful!
RE:
The leveling is inside the MK4 firmware.
You see it when you use a MK3s/+ gcode. Then the -new- MK4 automatic leveling starts, too.
RE: Always unwanted filament on noozle & sheet
Heat the bed BEFORE leveling makes sense. It's better under print conditions than on a cold bed -> more real results. I'm sure prusa had a reason to do that.
I had no time to take a closer look when what temp. is going on, I only saw that some temp. instructions are in the MK4 start code. I understand what you mean.
@MK4 - Heat the bed whenever you want, but I do'nt want crumbs on many of the leveling noozle touches left on the bed.
RE: Always unwanted filament on noozle & sheet
I will have a look to it as soon as I will receive the MK4 kit and I will assemble it.
For sure I don't want either, so I will change starting sequence.
RE: Always unwanted filament on noozle & sheet
Careful changing the starting sequence.
I don’t have my MK4 yet. But when one of the first Mk4s came out, I saw a video of the start sequence. The nozzle was NOT heated to extrusion temp but like 170 °C instead.
What happened? Well, I saw a lot of people complaining they had bits of plastic sticking out that did not get cleaned, so the bed leveling by tap would mess up and the 1st layer would be way too high. If the MK4 now heats to extrusion temp in the cleaning and leveling, it’s probably to fix the improper cleaning of the nozzle that was throwing off the bed leveling.
RE: Always unwanted filament on noozle & sheet
The latest configuration update for PrusaSlicer has addressed some of the issues I had during print start-up. Especially the purge line. But still leaving crumbs as you say on the sheet throughout the pre-print process.
RE:
The latest update does not solve the issue. No matter what filament you use.
These crumbs, sometimes up to 49? are hard to remove, the are pressed on because the noozle touches the sheet without a gap. And important, AFTER the so called noozle cleaning procedure.
I can not believe it, but I got as answer from prusa, please clean the sheet every time. There's no issue...
I have no time for such nonsens and let the MK3's do the work until, someday? this will be fixed.
Does anyone saw a $1000 printer, or $199 wich leaves the bed full of filament crap after print? Everytime.
RE: Always unwanted filament on noozle & sheet
... leaves the bed full of filament crap after print? Everytime.
...to say correctly, before the print starts.
RE: Always unwanted filament on noozle & sheet
Yes I still have the same issue, but I notice it is worse with some filaments over others. I pretty much use 1 brand but many different colors. Some colors do not leave the "crumbs" or only a few, while other colors leave what looks & feels like 49 of them like you said. I would like to take a closer look at the starting gcode but at this point it is not high on my list of priorities. I have another issue that is more annoying to me when changing filament mid-print but I don't want to hijack this thread.
RE: Always unwanted filament on noozle & sheet
It happens with every filament we use, and we use a lot, and different brands.
I think this don't must be discussed, it should never happen.
A small retract before the Z leveling would help, but prusa is not interested to solve this issue. To say better don't want to see or hear that.
RE: Always unwanted filament on noozle & sheet
I have, unfortunately, taken to cleaning the sheet after every single print with the MK4.
On the MK3S+, I clean the sheet way way less frequently.
RE: Always unwanted filament on noozle & sheet
same here with a preassembled mk4. Got it for 2 weeks now. it's getting worse and worse. changed the nozzle with no effect. 3 div types of petg.
RE: Always unwanted filament on noozle & sheet
I really don’t like the implementation of the bed leveling. Filament oozes everywhere. There’s no guarantee there won’t be oozing.
Instead of heating the nozzle with filament in it at some mid temperature, they should pull the filament back out of the hot part of the nozzle first (nozzle is very long), heat up the nozzle without any filament in it, then do a nozzle clean and bed level. Once that’s done, push the filament back down and do a looooong purge line (like the MKS3+ w/ MMU2S).
RE: Always unwanted filament on noozle & sheet
I prefer the way my Prusa Mini executes the bed leveling and lays down the first layer. No oozing filament, and no crumbs.
Wiping off the crumbs after a print is one thing, but correct me if I'm wrong: By leaving those crumbs on the bed during leveling process, they are going to get caught up in the first layer once it is layed down and some of them will stick in the first layer and make a mess of things, won't they?
With the Prusa Mini, the PLA temp was 170 for auto leveling, and no filament oozed out. In addition to that, it would make a big, long, thick line on the front after coming to temp but before printing the skirt. I read somewhere that that was for reducing the pressure in the nozzle.
Anyway, with the Prusa Mini I could hit print and walk away and it would do a nice clean print. With the MK4 I have to stand there with a paper towel and wipe the nozzle as 10 to 20mm of oozing filament comes dripping out of the nozzle. I don't want that messing up my bed and the print.
RE: Always unwanted filament on noozle & sheet
Even do the MK3S does not touch the bed I have unwanted filament hanging out of the nozzle, I manually retract the extruder 4 steps and then clean the nozzle with a brass brush, and when nothing is dripping I start the print.
David DLC
RE: Always unwanted filament on noozle & sheet
Does anyone know if Prusa is planning on fixing this or going to the old methodology for first layer like the Prusa MK3???
This issue is really taking away from the experience of owning a MK4 series printer. It does so many things great, but this issue is so frustrating.
I find myself using my Prusa Mini more and more just to avoid the first layer experience of the MK4.
I hope they have some plan of attack, and I hope they implement it soon.
RE: Always unwanted filament on noozle & sheet
Same issue here. Quite annoying I would say. And I'm not yet to the step the bed levelling is messed up by this tiny crumbs...