Why is my nozzle dragging across all of my prints?
I'm finding that my nozzle is dragging across the top surface of every full layer, and leaving drag marks along the finished surfaces. Finished surfaces are also too rough. Is this an extrusion issue or Lift-Z issue?
As you can see in the attached pictures, there are smooth lines drug through the top layer when the head is repositioned for infill in a different region. When the 1st layer isn't properly adhered, it can cause the print to break free. If the print is solid, it leaves a nice, smooth line from one side to the other. This is a single layer test image, printed with the default slic3r settings: 0.15 first layer, 1.75mm PLA, 210/55C.
In this one, you can see both the nozzle drag lines circled in red, but also the very rough finished surface. This is the stock Prusa file that came on the SD card with the printer.
Extrusion multiplier is 1.
Is the rough surface a function of over extrusion? If so, why wouldn't that show up on the 1st layer? If so, will the dragging go away if I were to change the extrusion multiplier?
Re: Why is my nozzle dragging across all of my prints?
You can eliminate this effect to some extent by enabling Z-hop in your Slic3r.
Vojtech
Re: Why is my nozzle dragging across all of my prints?
It appears that it might be both a Z lift and an overextrusion issue.
I deleted and reloaded all the Slic3r settings and Lo! the Lift Z setting was now 0.15mm, not zero. Part of the problem solved. The latest print didn't have the dragging. I'm not sure why the Prusa logo print has drag marks, so I'm reslicing it.
I wiped the nozzle, extruded an additional 10 (whatever the units are in the system), and measured it:
Measured as 1.18, divided that into 100 to get an extrusion multiplier of 0.847 that I put in the filament settings. The top surface is less rough and matte on the new print. Also incorporating this setting into the new Prusa reslice.
With the lower extrusion rate, you can see a much shinier surface and fewer drags on the lower fish. The upper fish has a very matte and rough to the touch surface:
However, there are still some areas where the extruder paused (?) that look like they're plowed in.
If by default it is extruding too much, could that mean that the nozzle temp is too high for this filament and that variable is the better one to be tweaking?
Re: Why is my nozzle dragging across all of my prints?
Are you sure it's the nozzle dragging and not the PINDA probe? When I first assembled my MK2 upgrade I had the probe too low and it dragged across parts of the printouts...
Re: Why is my nozzle dragging across all of my prints?
Are you sure it's the nozzle dragging and not the PINDA probe? When I first assembled my MK2 upgrade I had the probe too low and it dragged across parts of the printouts...
Thanks for asking. The PINDA probe would be disastrous! Yes, this is the nozzle. I've got my PINDA probe set a bit high so my Z offset is -250, but that wouldn't explain why the stock Prusa logo would be dragging unless I reslice and put in Lift Z.
Re: Why is my nozzle dragging across all of my prints?
Curtis
You think there may be some over-extrusion, then it would be best to calibrate the feed.
Insert a light-coloured filament and measure 110mm from the top of the extruder and mark the filament. Extrude 100mm (using Pronterface etc), then measure from the top of the extruder to the mark.
Adjust the steps accordingly, but remember, that there are many reasons for under/over extrusion including but not limited to:
Filament diameter (this does vary across a roll of filament)
The hardness of the filament (which can even vary according to colour pigment)
The tightness of the filament drive tension screws
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is my nozzle dragging across all of my prints?
Curtis
Apologies, forgot to mention, you will always get some marking on the top surface due to nozzle moves. The only way to prevent this is by using Z Lift which may be difficult to apply to the top layer only as in general it is a who-model-print setting.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is my nozzle dragging across all of my prints?
My nozzle has never left marks on the top of my prints Peter...
Re: Why is my nozzle dragging across all of my prints?
Maybe it's a slicer thing then, but I am sure I also saw the issue on the Prusa logo file from the SD card (I can't find my print at the moment to check out).
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is my nozzle dragging across all of my prints?
Ok, I think I may be missing something, what does the length of the extrusion have to do with the over-extruding. That is a function of temp, nozzle size, feed rate and filament diameter resulting in extrusion diameter. Granted that there is a pull factor when the extrusion contacts the bed or object, however that factor is not one that I normally consider. Am I missing it?
Re: Why is my nozzle dragging across all of my prints?
Jay
That is precisely why I moved the conversation to the amount of filament fed into the printer.
Measuring the length of the extrusion has no meaning; it is the volume extruded (the diameter of the extrusion will vary depending on a few factors).
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…