Cura Seems to Miss Out Perimeters on Models

[Paul @carnivalius]

So I’ve been using the most up to date version of AM on Cura and while the supports are nice and the time for it to slice objects is really good, I have been noticing that part way through a print it seems like the printer misses perimeters. This leaves little rings round the objects with no perimeter and if the infill is low it’ll just snap off.

This seems to occur even without supports enabled as I printed two statues and both of them had missing perimeters at the same point (so not a jam at certain points). I’ve seen this “banding” on at least three different objects I’ve tried to print.

I’ve attached a photo of my latest print (in progress, hence poor resolution), but as you can see it’s missed out perimeters on several layers but only on the top part of the maw, the lower jaw doesn’t show this (even on the same layers), so would discount a jam/unjam scenario (I’d expect it to jam at least once on the smaller object).

Overall I’m happy, but this missing of perimeters makes it hard to clean up my prints or polish them. I didn’t know if anyone else had seen these issues or a simple solution? At the moment it seems to be the way the software slices and processes the objects (either on Cura or AM’s end).

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[Paul @carnivalius]

I have run both printjob .gcodes through http://gcode.ws/ and I cannot see an obvious missing of layers. It’s almost like the printer has decided not to open the valve correctly for the outside perimeters.

Anyway I include a dropbox link incase anyone is interested in seeing more or having a delve themselves.

 

https://www.dropbox.com/sh/sg8kp4059yq3t8z/AADCC_C1ajNAiP39BAUDvFQPa?dl=0

[BHudson @bhudson My Robox is a Green Kickstarter Beta]

I have seen that behavior before. It is usually related to one of two things:

1. There is a wall thickness that is too small for Cura to evaluate. Anything less than about .030 inches doesn’t sometimes get sliced properly. This leads to skipped layers elsewhere.

2. The slicer has changed the extrusion to accommodate a solid infill layer or bridging. This can lead to over- or -under extrusion in certain circumstances.

I would try the same print with Slic3r and see if you get the same result. If so, look for a thin wall somewhere at that level.

I am not affiliated with CEL; I operate two Betas and one Production Robox.

[Paul @carnivalius]

Thanks for that. You’re idea of using Slic3r was a good one. Using that it only printed the support structures (usually an issue with manifolds if an object doesn’t print at all).

I then realised I had not checked the model was actually manifold as I had assumed it was fine. Netfabb agreed, so I’ve now repaired it and left it printing again while I go to work.

So hopefully I’ll be able to post a picture of the print later to see if the problem has gone away.

[poju @poju My Robox is a Blue Commercial Version]

Today i found out that in some models you need to run 2 times netfabb to fix them properly, first run do not fix all intersections

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