slicing revolved / axisymmetric parts

Hello,

I have a part that is composed of a revolved feature - that is, a part that could be produced on a lathe. Cura is doing a poor job of producing it.

The entire part could be produced with extruded circles, which would be very fast and neat. However, I don't see any way to do 'polar' fill patterns. So cura is doing all the infill between circular shells in a cartesian pattern. This makes a tonne of opportunities for blobbing and is killing the quality of the part.

Also, It is travelling up z in the same location (at the top of the pic) so all the minor blobs from z travel are adding up in the same location, causing a mess.

Is there a way to get polar infill patterns?

Is there a way to randomize where the layer begins so that all the blobs don't happen in the same place?

Im sure Sli3r can do both of those. But that doesnt answer your question.

Switching back to slicer, I can see there is a concentric fill option. Although it didn't actually do so on the first 3 layers, it just layed them down linear.

I am running a 0.4mm magma hot end so I've designed the wall thicknesses all as 1.2mm. For some reason however, both slicer and cura fill the walls in one solid circle followed by a dashed circle(very slow) then another solid circle.

If you unwrapped the circles it is printing, the three layers look like:

--------------
- - - - - - - -
--------------

The middle ring is extremely slow and makes everything messy from all the stop starts. I just want this thing to extrude out lots of concentric rings!

Here's a good diagram. This is sliced in Cura but slicer does the same thing.

You can see the middle extrusion of each wall is a dashed line instead of a concentric ring.

I confirmed this is because the slicer is making some sort of assumption that the extrusion will be different in width than the nozzle. I remodelled the part with 1.3mm walls instead, and it now prints 4 continuous concentric rings nice and fast. The bottom layers filled in concentric also as I set the shell thickness high.

Only problem is cura still steps up z in the same place every time blobbing that region. Any fix to that?

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mullenc525
Only problem is cura still steps up z in the same place every time blobbing that region. Any fix to that?

Sounds like you may need to tweek your retraction settings.

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mullenc525
confirmed this is because the slicer is making some sort of assumption that the extrusion will be different in width than the nozzle. I remodelled the part with 1.3mm walls instead, and it now prints 4 continuous concentric rings nice and fast. The bottom layers filled in concentric also as I set the shell thickness high.

I've printed quite a few tube shapes (as adaptors to my workshop vacuum cleaner to connect to various power tools), and I've found that none of the slicers make a good job at getting the internal diameter correct.

I've also tried setting my wall width to a multiple of the nozzle width, but that didn't work.

Based on what you've seen it looks like Cura is adding about 8.33% (1.3 instead of 1.2) to the width in its calculation - which seems very odd