Problem with large prints
I have no issues at all with small prints, but as soon as I go to larger prints, the first layer looks pretty damn bad (pla lifts itself from the bed), no matter what I do.
The nozzle height should be perfect, live adjust Z is at -950, according to manual it should be perfectly fine, lines look really good, no over or underextrusion.
Roughed up the PEI sheet with a sponge, tried old and completly new PLA (was still sealed up till seconds ago), tried to get the nozzle further away from the bed + increased first layer height, tried different speeds, temperatures, but nothing will get me a satisfactory first layer with large prints.
I suppose my large prints catch/scratch the infill later on, because the first layer is not perfect.
I ran every calibration possible multiple times, checked my extrusion and everything else.
Small prints are fine, just printed a nearly perfect benchy yesterday.
Large prints on the other hand, do not want to work.
I do have a bottle of Magigoo, but I dont want to resort to that with mere PLA where there should be no adhesion problems whatsoever.
Im out of ideas, anyone?
Edit: Das Filament PLA, this print was 215°/60° (specs of the filament, tired diff. temps too), the blob at the end is there, because I stopped the print.
With the same exact print settings I printed out the benchy. Thats what confuses me to no end. Perfect small prints, big prints catch on infill and have bad first layers.
Re: Problem with large prints
Are you cleaning the bed with isopropyl alcohol before every print? I know I get some similar looking issues if I don't clean the bed. I've made it a habit at this point.
Re: Problem with large prints
Forgot to write that, surely I clean with isoprop every time before I print.
Re: Problem with large prints
From my experience being a little too close to the bed causes that ripple effect. It would also explain the nozzle hitting infill. I would try raising the nozzle, just a hair(or less lol).
Re: Problem with large prints
I just found the issue.
Being too much of a perfectionist can hurt sometimes 😆
Basicly, my first layer was so perfect, that the 150% first layerheight was wayyy to much and too much filament was being squeezed on the surface in tight spots.
Im now down to 120% and I dont have ripples anymore.
I hope I wont have problems with infill now.
And the nozzle isnt too close to the bed, I just did the first layer gcode from jeff out of the forum here, and basicly my first layer was perfect with his gcode.
Thats why I was wondering.
Well, first layer issues are now fixed, lets see if I still have problems with infill scratching.
Edit: Well I take it back, still have ripples, but not even half as bad as before, apparently even 120% first layer height is way too much. I´ll just try 100%.*
Edit2: At 100% its nearly perfect, only a few rough places left, bumped down my overall extrusion from 1.05 to 1.00.
Set the live z adjust a tad bit higher (from -970 to -950).
If thats not enough, I´ll lower the first layer height down to 95%.
Re: Problem with large prints
As I understand first layer height settings, they just change -as the name suggests- the first layer height BUT also change the amount of filament extruded accordingly, so in theory, if everything else is tuned perfectly, your ripples should not get any better, no matter how much you reduce your layer height percentage, the amount of extruded filament will reduce but the nozzle will move down accordingly which leads to no change in the height/filament extruded ratio.
So as you said, you should just up your live z and/or reduce extrusion multiplier.
Re: Problem with large prints
Did you do manual mesh bed leveling? I had problems as you describe for large prints with my MK2S and needed this manual calibration. I made my own test model for calibration as I didn't like the ones from Thingiverse.
- Martin
- Martin
Re: Problem with large prints
Did you do manual mesh bed leveling? I had problems as you describe for large prints with my MK2S and needed this manual calibration. I made my own test model for calibration as I didn't like the ones from Thingiverse.
- Martin
Sorry to hijack this.. Calibration is one thing I am confused about.. Whats the difference between Bed Leveling and Z-Height adjust.
On my Printrbot the bed leveling is automatic, and I adjust my Z height using M212 (I think its 212)...
Could someone take a min and explain the process on the Prusa?
Re: Problem with large prints
Sure. Bed leveling is making sure that your nozzle keeps an equal distance from the bed in all of its travel at a set distance from the bed. This is assuming your bed is perfectly flat. Z height adjustment is what that height is at your first layer.
So bed leveling is for the X and Y travel of your nozzle to be parallel to the bed at any given height of Z.
Z height adjustment is altering that distance for the amount of squish in your filament as it lays down on the bed and later on the filament below it.
Hope that helped,
Neal
On a side not you may hear some refer to it as "tram". This is actually what you are doing but "bed leveling" is term used most often.
Re: Problem with large prints
Sure. Bed leveling is making sure that your nozzle keeps an equal distance from the bed in all of its travel at a set distance from the bed. This is assuming your bed is perfectly flat. Z height adjustment is what that height is at your first layer.
So bed leveling is for the X and Y travel of your nozzle to be parallel to the bed at any given height of Z.
Z height adjustment is altering that distance for the amount of squish in your filament as it lays down on the bed and later on the filament below it.
Hope that helped,
Neal
Right.. I think this is where I am confused as my Printrbot does its bed level check before EVERY print.. It only checks 3 points, so is pretty quick, but it does it every time.. Where as my Z height is locked in NV RAM..
So on the Prusa, you do the Level Calibration ones (or as often as needed).. And then set your Z height using Live Adjust (again as often as needed)..
Re: Problem with large prints
I was referring to the manual mesh bed levelling. The printer does an automatic levelling using the PINDA probe, but the probe is rather inaccurate and you have to manually fine-tune it. At least, I had to for large prints as they would stick fine in the center, but lift off in the top left.
- Martin
- Martin
Re: Problem with large prints
Purty much. But that nine point check that the Prusa does before every print is its version of checking bed level-ness. Live Z adjust is great for when you change filaments about. The calibration squares and other methods kinda set you up in the general area. But as you know the differences in filaments by type, manufacturer, and even color can be pretty spread out so the Live Z lets you tweak on the fly without changing your standard settings.
Neal