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MK4 questions, comments, observations  

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TeeBell
(@teebell)
Trusted Member
MK4 questions, comments, observations

First full day with new MK4 (factory assembled, of course). Out of the box the X-Axis failed calibration. It ended up being that I had to loosen the belt a hair, now it passes the test.

This MK4 is replacing an MK3S (not +) which was my first Prusa a few years ago. I have 5 other MK3S+ and they all pretty much print non-stop. I bought a Mini when it first came out but sold it soon after buying and went with more MK3S+ models. 

It feels like the MK4 user experience has been dumbed down in that there are a lot more steps to perform simple functions. I don't quite understand the usefulness of seeing an image of the print on the screen while printing but then again I'm an old command-line guy. I have not yet figured out how to disable that feature, if it is possible, and replace it with more useful info like bigger text for temps, time remaining, and time to next color swap which is the most useful feature I miss. 99% of my prints do color swaps so I need to be able to look at the screens and see when I am needed next. Yes I do them all manually. And on that topic, the process of changing filament is surely different than the MK3S+ process and I just have to get used to it I guess. One the new color is in and the old color purged, telling the printer to resume the print sends the extruder flying to where it left off. Better be quick about yanking off the filament string!

I had updated the start gcode for the MK3S+ so that it would do the mesh level check at a temp of 160 to stop the oozing and dots of filament as it levels. I noticed this on the MK4 today, it left behind dots of filament as it was doing the pre-print mesh level. The temp is set to 170 and am thinking of changing it to 160. I print with PLA only.

If other MK4 users have info on any of my desired changes please feel free to share! I will keep scouring the help sections. And I'm sure I will be posting updates along the way.

Happy printing!

Posted : 09/05/2023 12:52 pm
iftibashir
(@iftibashir)
Honorable Member
RE: MK4 questions, comments, observations

I also do manual color swaps - didn't realize the MK4 doesn't give you the time to the next swap though! Why would they remove that? Such a small, but useful indicator!!!

Whats different with the filament change process?

ORIGINAL PRUSA MK4 KIT - Full step-by-step video assembly guide!

>ORIGINAL PRUSA MINI+ Full video assembly guide!

Posted : 09/05/2023 1:18 pm
Walter Layher
(@walter-layher)
Honorable Member
RE: MK4 questions, comments, observations

I have also done a few prints on my MK4 with color changes that were added in PrusaSlicer. I did not feel a big difference in the time until the print head returned back compared to my MK3S+. I always keep the fingers of one hand near the nozzle, then I press "continue" with my other hand, wait a bit for the oozing to begin and then I grip the strand just when the head starts to move. Works just as on my MK3S+. Just the knob on the display acts a bit more immediately compared to the one on the MK3S+, which needs two "clicks" for one action where the knob on the MK4 reacts on the first "click" when you turn it.

Posted : 09/05/2023 1:44 pm
Jeremy
(@jeremy-3)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @iftibashir

I also do manual color swaps - didn't realize the MK4 doesn't give you the time to the next swap though! Why would they remove that? Such a small, but useful indicator!!!

Whats different with the filament change process?

The MK4 firmware is pretty bare bones right now – many things like crash detection, full screen stats, color swap info, input shaping, Octoprint command support, etc will be slowly added over time. I know there’s a Top 10 list of items they’re planning to add in, but it’ll take time.

Posted : 09/05/2023 2:23 pm
TeeBell
(@teebell)
Trusted Member
Topic starter answered:
RE: MK4 questions, comments, observations

It does give time to do the swap. But once you confirm that you are ready to continue with the new color the head moves to the print location much faster than MK3S. 

Posted : 09/05/2023 2:29 pm
BrutusBoots
(@brutusboots)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @teebell

First full day with new MK4 (factory assembled, of course). Out of the box the X-Axis failed calibration. It ended up being that I had to loosen the belt a hair, now it passes the test.

This MK4 is replacing an MK3S (not +) which was my first Prusa a few years ago. I have 5 other MK3S+ and they all pretty much print non-stop. I bought a Mini when it first came out but sold it soon after buying and went with more MK3S+ models. 

It feels like the MK4 user experience has been dumbed down in that there are a lot more steps to perform simple functions. I don't quite understand the usefulness of seeing an image of the print on the screen while printing but then again I'm an old command-line guy. I have not yet figured out how to disable that feature, if it is possible, and replace it with more useful info like bigger text for temps, time remaining, and time to next color swap which is the most useful feature I miss. 99% of my prints do color swaps so I need to be able to look at the screens and see when I am needed next. Yes I do them all manually. And on that topic, the process of changing filament is surely different than the MK3S+ process and I just have to get used to it I guess. One the new color is in and the old color purged, telling the printer to resume the print sends the extruder flying to where it left off. Better be quick about yanking off the filament string!

I had updated the start gcode for the MK3S+ so that it would do the mesh level check at a temp of 160 to stop the oozing and dots of filament as it levels. I noticed this on the MK4 today, it left behind dots of filament as it was doing the pre-print mesh level. The temp is set to 170 and am thinking of changing it to 160. I print with PLA only.

If other MK4 users have info on any of my desired changes please feel free to share! I will keep scouring the help sections. And I'm sure I will be posting updates along the way.

Happy printing!

when the image of the print is on the screen, click the knob and it'll show you the print info screen.  You can customize what items it displays in the footer.

Posted : 09/05/2023 5:15 pm
Jeremy
(@jeremy-3)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @brutusboots

 

when the image of the print is on the screen, click the knob and it'll show you the print info screen.  You can customize what items it displays in the footer.

Yeah, the configurability they're giving helps a lot.  I think they're planning on making it configurable on if you want it to go straight to the info screen.

Posted : 09/05/2023 6:08 pm
TeeBell liked
iftibashir
(@iftibashir)
Honorable Member
RE: MK4 questions, comments, observations

I’m guessing all those configuration changes you can make are all reset again with a new firmware update though?……

ORIGINAL PRUSA MK4 KIT - Full step-by-step video assembly guide!

>ORIGINAL PRUSA MINI+ Full video assembly guide!

Posted : 09/05/2023 7:00 pm
BrutusBoots
(@brutusboots)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @iftibashir

I’m guessing all those configuration changes you can make are all reset again with a new firmware update though?……

 

unless they indicate so, I don't see why any settings would be lost.

Posted : 09/05/2023 7:02 pm
TeeBell
(@teebell)
Trusted Member
Topic starter answered:
RE: MK4 questions, comments, observations

Lots more prints today. Still trying to understand all that happens once I hit Print and when the actual print starts. The purge line seems odd...instead of one long line it is a a very short line to the right and then back to the left. I am guessing that can be changed in the start gcode?

I have also noticed that there is a bit of a string that oozes out of the nozzle after the leveling is done at 170 degrees and while it heats to 215 (this is the profile for Hatchbox PLA). The purge line I mentioned doesn't necessarily take care of this because it is so short the string either sticks up or catches on the nozzle and before you can do anything the purge line is reversing course right back on top of it.

Posted : 09/05/2023 7:23 pm
BrutusBoots
(@brutusboots)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @teebell

Lots more prints today. Still trying to understand all that happens once I hit Print and when the actual print starts. The purge line seems odd...instead of one long line it is a a very short line to the right and then back to the left. I am guessing that can be changed in the start gcode?

I have also noticed that there is a bit of a string that oozes out of the nozzle after the leveling is done at 170 degrees and while it heats to 215 (this is the profile for Hatchbox PLA). The purge line I mentioned doesn't necessarily take care of this because it is so short the string either sticks up or catches on the nozzle and before you can do anything the purge line is reversing course right back on top of it.

Here's my routine...  Clean the bed with ISO, Start the print, wait for the nozzle to hit 170, use a long pair of tweezers to remove any excess filament from the nozzle.  Walk away.  My job is done.  This printer needs way less babysitting than the MK3S (not that it needed much) but the MK4 is very fire and forget.

Posted : 09/05/2023 7:29 pm
Jeremy liked
TeeBell
(@teebell)
Trusted Member
Topic starter answered:
RE: MK4 questions, comments, observations

 

Posted by: @brutusboots

 

Posted by: @teebell

Lots more prints today. Still trying to understand all that happens once I hit Print and when the actual print starts. The purge line seems odd...instead of one long line it is a a very short line to the right and then back to the left. I am guessing that can be changed in the start gcode?

I have also noticed that there is a bit of a string that oozes out of the nozzle after the leveling is done at 170 degrees and while it heats to 215 (this is the profile for Hatchbox PLA). The purge line I mentioned doesn't necessarily take care of this because it is so short the string either sticks up or catches on the nozzle and before you can do anything the purge line is reversing course right back on top of it.

Here's my routine...  Clean the bed with ISO, Start the print, wait for the nozzle to hit 170, use a long pair of tweezers to remove any excess filament from the nozzle.  Walk away.  My job is done.  This printer needs way less babysitting than the MK3S (not that it needed much) but the MK4 is very fire and forget.

I'm not feeling that way at all. Maybe in time. With the updated start gcode on the MK3S it was definitely hit print and walk away. And with a number of fewer clicks. Every morning I could start 6 prints and go back to bed or make coffee or whatever. Come back to a long purge line at the bottom edge of the plate and peel it off. Or not. Never in the way. Not the case on MK4 it puts the purge line very close to the start of the print. It's so short, if I try to pick/peel it off more often than not the extruder is quickly coming for my hand. I'd leave it but if there was any oozing there could be a line possibly interfering with theprint. I'm sure folks will "fix" the start gcode.

Posted : 09/05/2023 7:39 pm
Jeremy
(@jeremy-3)
Trusted Member
RE:

I think it sounds more like an issue with your filament causing the oozing then the overall routine being bad.  You could change the temp in the start code to be say 160 instead of 170, but otherwise a purge line is a purge line and if you have oozing, it's going to be there regardless of where the purge line is.  I find the 6 inch long tweezers work great for those scenarios where I've had an oozing filament in the past.

The purge line is close to the print now because of the localized-only bed leveling.  Not saying it's a perfect solution, but it has its purpose.  I've never removed a purge line prior to a print - only used the tweezers on the fine hair trail if needed.

Posted : 09/05/2023 7:47 pm
BrutusBoots
(@brutusboots)
Trusted Member
RE: MK4 questions, comments, observations

 

Posted by: @teebell

 

Posted by: @brutusboots

 

Posted by: @teebell

Lots more prints today. Still trying to understand all that happens once I hit Print and when the actual print starts. The purge line seems odd...instead of one long line it is a a very short line to the right and then back to the left. I am guessing that can be changed in the start gcode?

I have also noticed that there is a bit of a string that oozes out of the nozzle after the leveling is done at 170 degrees and while it heats to 215 (this is the profile for Hatchbox PLA). The purge line I mentioned doesn't necessarily take care of this because it is so short the string either sticks up or catches on the nozzle and before you can do anything the purge line is reversing course right back on top of it.

Here's my routine...  Clean the bed with ISO, Start the print, wait for the nozzle to hit 170, use a long pair of tweezers to remove any excess filament from the nozzle.  Walk away.  My job is done.  This printer needs way less babysitting than the MK3S (not that it needed much) but the MK4 is very fire and forget.

I'm not feeling that way at all. Maybe in time. With the updated start gcode on the MK3S it was definitely hit print and walk away. And with a number of fewer clicks. Every morning I could start 6 prints and go back to bed or make coffee or whatever. Come back to a long purge line at the bottom edge of the plate and peel it off. Or not. Never in the way. Not the case on MK4 it puts the purge line very close to the start of the print. It's so short, if I try to pick/peel it off more often than not the extruder is quickly coming for my hand. I'd leave it but if there was any oozing there could be a line possibly interfering with theprint. I'm sure folks will "fix" the start gcode.

I just finished my 80th print and I've not had any issues with the purge line.  Making sure that you don't have a big string of filament in your nozzle when you first start the print is key.  That was always the case with the MK3S as well though.

Posted : 09/05/2023 7:52 pm
fuchsr
(@fuchsr)
Famed Member
RE: MK4 questions, comments, observations

The purge line seems odd.

I'm still waiting for my Mk4 kits but I think the purge line is the same as the one used by my XL. I've replaced it with the one used in the popular Bob George startup code. On the other hand, I like the new positioning close to the model, so I changed my Mk3S and Mini startup codes to put the line down in that area 🙂

If you want the purge line to behave more like the Mk3S purge line, you could try replacing this code in the Mk4 startup gcode

M104 S[first_layer_temperature] ; set extruder temp
G0 X{(min(print_bed_max[0], first_layer_print_min[0] + 32) - 32)} Y{(max(0, first_layer_print_min[1]) - 4) + 4 - 4.5} Z{30} F4800

M109 S[first_layer_temperature] ; wait for extruder temp
G1 Z0.2 F720
G92 E0

M569 S0 E ; set spreadcycle mode for extruder

;
; Extrude purge line
;
{if filament_type[initial_tool]=="FLEX"}
G1 E4 F2400 ; deretraction
{else}
G1 E2 F2400 ; deretraction
{endif}

; move right
G1 X{(min(print_bed_max[0], first_layer_print_min[0] + 32) - 32) + 32} E{32 * 0.15} F1000
; move down
G1 Y{(max(0, first_layer_print_min[1]) - 4) + 4 - 4.5 - 1.5} E{1.5 * 0.15} F1000
; move left
G1 X{(min(print_bed_max[0], first_layer_print_min[0] + 32) - 32)} E{32 * 0.30} F800

G92 E0

with

M104 S[first_layer_temperature] ; set extruder temp
G0 Z0.15 ; Restore nozzle position
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0 ; reset extrusion distance
M109 S[first_layer_temperature] ; wait for extruder temp
M569 S0 E ; set spreadcycle mode for extruder

; Prime line
G1 E2 F1000 ; de-retract and push ooze
G1 X20.0 E6  F1000.0 ; fat 20mm intro line @ 0.30
G1 X60.0 E3.2  F1000.0 ; thin +40mm intro line @ 0.08
G1 X100.0 E6  F1000.0 ; fat +40mm intro line @ 0.15
G1 E-0.8 F3000; retract to avoid stringing
G1 X99.5 E0 F1000.0 ; -0.5mm wipe action to avoid string
G1 X110.0 E0 F1000.0 ; +10mm wipe action
G1 E0.6 F1500; de-retract
G92 E0.0 ; reset extrusion distance 

This is basically the Bob George prime line, in the old position.

CAVEAT: Again, I don't have a Mk4 yet to test it on. So don't shoot me if it doesn't work. It assumes that the nozzle will be in home position after MBL, if not, it may need a G28. And I have no idea what the M569 S0 E command does but added it because it's in the original Mk4 code.

Posted : 09/05/2023 9:31 pm
TeeBell liked
ironfan72
(@ironfan72)
Trusted Member
RE: MK4 questions, comments, observations

The problem with putting the purge line in the Mk3 position is that the bed has not been levelled there. As the Mk4 only levels the bed in the print area it makes sense to put the purge line down in the same area.

The thing I have noticed is that even after doing the 3 nozzle cleaning spots I still get bits of filament left on the bed at all/most of the bed levelling positions. I can feel it when I try to clean the bed afterwards and usually need to use a scraper to clean them off the bed. Maybe a lower temperature (<170) would help with this.

Posted : 12/05/2023 6:16 pm
TeeBell
(@teebell)
Trusted Member
Topic starter answered:
RE: MK4 questions, comments, observations

 

Posted by: @ironfan72

The problem with putting the purge line in the Mk3 position is that the bed has not been levelled there. As the Mk4 only levels the bed in the print area it makes sense to put the purge line down in the same area.

The thing I have noticed is that even after doing the 3 nozzle cleaning spots I still get bits of filament left on the bed at all/most of the bed levelling positions. I can feel it when I try to clean the bed afterwards and usually need to use a scraper to clean them off the bed. Maybe a lower temperature (<170) would help with this.

Yes this is exactly what I have noticed as well.

Posted : 12/05/2023 7:02 pm
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