Solid infill layers not adhering properly
Hey all,
I've noticed some odd behavior on the solid infill layers for large prints on my MK3S. Not sure if it's a problem with bed leveling, z height, or what...
The solid infill layers don't adhere properly (see the picture below), causing lumps of filament that affect following layers drastically and sometimes even result in crashes.. I've only noticed this in large prints with these settings but I've not tested anything super exhaustively. Generally, everything seems to work just fine in small prints. The only thing that seems to help with these large prints is changing the print speed down to about 80% which is obviously not ideal since keeping it there can add hours to the print time if done through the entire print. This is printed at 190C nozzle temp and is the best result I've seen so far, but I've tried varying temperatures all the way up to 215 with similar results. This is .2mm layer height on a .4mm nozzle. I can only assume this is some kind of settings problem, but not sure what settings to try adjusting and whether they would be in the slicer or on the printer itself.
Thanks in advance for what I'm sure will be helpful advice 🙂
Best Answer by --:
Acceleration explains why the smaller areas (and near the perimeters of this large part) are working for you. Be aggressive with the flow; try 8, then 4. Many have said 11 is about the true max with most PLA. I've shown the printer will do 15, but only on a limited range of PLA I use.
It's also worth previewing the actual print speed in slicer; and follow what is really happening as you change flow rates. Once you dial in what works you can then adjust everything to get the quickest prints within the limitations of the printer/filament.
Also - just curious - are you using a brass or steel nozzle?
RE: Solid infill layers not adhering properly
The image is symptomatic of trying to print too fast. Essentially exceeding the filament/hot end volumetric extrusion rate. PLA is somewhere above 10 mm3/s; but PETG is much less, 4mm3/s. Without knowing the details of what and how you are printing, it's guesswork trying to explain exactly what's happening.
RE: Solid infill layers not adhering properly
@tim-m30
Printing too fast is in line with the fact that slowing the print down helps... This is Overture PLA using the stock PrusaSlicer settings (other than temperature, as mentioned). Looking at the settings, it says max volumetric speed is 15mm3/s, I can try lowering it down by a few to see what happens. As far as the model goes, this is just a test design (150mmx150mmx1mm slab) to get long travel distances of solid infill - I haven't seen this problem in smaller models.
RE: Solid infill layers not adhering properly
Acceleration explains why the smaller areas (and near the perimeters of this large part) are working for you. Be aggressive with the flow; try 8, then 4. Many have said 11 is about the true max with most PLA. I've shown the printer will do 15, but only on a limited range of PLA I use.
It's also worth previewing the actual print speed in slicer; and follow what is really happening as you change flow rates. Once you dial in what works you can then adjust everything to get the quickest prints within the limitations of the printer/filament.
Also - just curious - are you using a brass or steel nozzle?
RE: Solid infill layers not adhering properly
@tim-m30
It's a brass nozzle; the default E3D v6 that comes with the Mk3S kit.
RE: Solid infill layers not adhering properly
Thanks for all the help Tim. Ran some prints today and changing that setting made immediate improvements. Now it's just a matter of optimizing everything.