2 minutes ago, gr5 said:
Look at your sliced model in PREVIEW mode and step through the lines as they are being drawn. In some places where your printer slows down - are there more points closer together?
I would understand if there was any geometry deviation. But there is no deviation and inconsistency in geometry. It is circular walls. Also model exported in 3MF to avoid ugly triangulation with STL. I suspect that neither Cura or Marlin 2 supports arcs so it's still getting split into direct lines. By 3MF I'm just trying to minimize amount of splitting it into lines.
I suspect that it's not the point of bad model and bad triangulation. It's made in SolidWorks, so it's not a mesh.
I saw posts about something similar caused by a bug in Cura 4.7 (that's why I didn't update), but I'm using 4.6.1 and this effect is not that pronounced.
Attaching screenshot of speed in Cura. Looks even.
I don't understand why vase mode prints perfectly. If there's issue with gcode line buffer, it would affect vase mode too - during 1 full line it have to have more than 16 lines considering it's a circle, not a rectangle.
I don't know much about the ender3 but it uses Marlin firmware and these types of printers (like Ultimaker printers) have typically either an 8 or 16 line gcode buffer. They have to plan the next 8 or 16 steps constantly as it's printing because if the very next gcode is a sharp corner the printer needs to be able to come to almost a complete stop without violating the acceleration criterea.
So if there are too many points (say 1 every 0.1mm) then it will print slow. And then in areas where there are fewer points/gcodes the printer will speed up.
Look at your sliced model in PREVIEW mode and step through the lines (horizontal slider - not vertical!!!) as they are being printed. In some places where your printer slows down - are there more points closer together? If so you may have to fix this in your CAD export step. Or you can import your model in meshlab to see what you CAD did and you can reduce the polygons a bit - maybe have the polygons at least 2mm across for the most part:
Of course this doesn't completely explain why vase mode is better. Still - looking in PREVIEW mode should give you some hints as to the problem.
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