Extenal Corners Issue
Hi,
Finding new Mini prints the test objects very well. However, when I try to print anything with an external corner I am finding that the tips of the corners are always deformed as in the picture below.
The above is printed in PETG at 0.25 layer height and 100% speed.
Higher print speeds magnify the issue but I've tried slowing the outer perimeter down to a crawl and I still get the same result albeit to a slightly lesser extent.
This happens with PLA and PETG, with the latest firmware and new Beta firmware.
Finer layer height/quality settings help a bit but I need this to print as fast as my Mk3.
The picture below is the same model printed on my Mk3S at a print speed of 200% and 0.3 layer height and as you can see it is perfect. The first few layers look spaghettified due to a 45% bevel on the object:
I've checked and adjusted all mechanical parts which all seem fine and have tried rotating the print at 45 and 90 degrees but get exactly the same results so I and am now convinced that it is either a settings or software issue.
Any ideas?
RE: Extenal Corners Issue
Looks like oozing when speed is low (turning the corner). Linear Advance should correct for the problem with the right k-value (filament and printer dependent).
PrusaPrinters on the subject: https://help.prusa3d.com/article/t5w9VsdVai-linear-advanced
The next version of firmware will be using Linear Advance 1.5 (I think the Mini already has it).
Marlin has a k-factor generator to print a test pattern: https://marlinfw.org/tools/lin_advance/k-factor.html
The k value is set in PrusaSlicer GCode (expert setting).
Have a look at my models on Printables.com 😉
RE: Extenal Corners Issue
@area51
That k factor generator just about ruined my Mini bed. The resulting gcode just drives the nozzle into my bed and starts leaving a mark. I'm not sure exactly why or how it's doing that. Everything else I print leaves a nice first layer so somehow it's ignoring the settings on the printer for the first layer height. I don't see anything unusual in the beginning gcode that would explain that.
RE: Extenal Corners Issue
@rick-m12
I had the same experience after generation the code and just running it on the Mini - Nozzle was to low and I had to stop the print. Was sure I did an error, but diden't investigate to cause...
Maybe it will be more safe to handcraft the g-code for the k-value test, based on PrusaSlicer generated start and end g-code.
Have a look at my models on Printables.com 😉
RE: Extenal Corners Issue
I was able to run the k-factor generated g-code by replacing the beginning (and ending) portions of it with those portions of g-code taken from one of my current sliced objects.
RE: Extenal Corners Issue
@area51
I sort of fixed it by copying the beginning of another Mini gcode file and replacing the lines in the linear advance test gcode file. I was able to run it but it still doesn't look right. The print was severely squished much thinner than a normal first layer so there's still something odd going on. Because of that I'm not trusting the result.