Why does my print have stability issues (floating object part) in my slicer?

[ekaj_999]

I have just finished a model and when slicing it in PrusaSlicer, it is flagged for 'floating object part':

PrusaSlicer Error

On closer inspection it looks like there is a layer missing:

Layer missing in PrusaSlicer

I'm not sure why this is, because I was very careful to extrude this top tab of my model to the face it connects to in Fusion 360 to ensure it was properly attached:

Extruding to surfaceFinished model

The error message disappears when I enable supports in PrusaSlicer, but I was wondering if I had done something wrong during the modelling process, and maybe I can fix it so the printer doesn't need to add supports for this part?

[TheCADWhisperer]

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@ekaj_999 wrote:

I was wondering if I had done something wrong during the modelling process, and maybe I can fix it so the printer doesn't need to add supports for this part?

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@ekaj_999 

Modeled incorrectly.

Q1. Did you intend for this to be 4 different bodies (some of which are intersecting which is not possible in the real world) - or did you intend for 1 body?

Q2. Why are some of your sketches not fully defined?

Q3. What do you observe if you zoom in here?

We can start over from scratch to do this correctly step-by-step if interested.

MainBody Sketch1 arc is missing a dimension?  How big is that arc supposed to be?

[ekaj_999]

Thanks so much for the reply 😁

1. I did intend for this to be one body but in my head I split it into 3 sections (main body, top tab and side tabs) so I could assemble them at the end - I don't think this is best practice but my thought process was that I would have to go back to each element many times to tweak dimensions and it would be easier to find the relevant sketches to work on a specific part if I split the model into parts (and I didn't think this would cause any issues when exporting) 

2. The model that I'm making is for a game controller, I only measured the dimensions of where it needs to slot into (the rectangle on sketch 1) and estimated the other dimensions such as the arc as my plan was to 3D print it initially, place it into the controller and then tweak the other dimensions slightly based on feel and how it moves in the slot

3. Ah it does seem like there is a gap there which explains the error in the slicer - I would really like to fix this and improve my knowledge of Fusion and workflow as I'm making a lot of mistakes it seems -

I've defined it now as 2.2mm from the edge of the rectangle to the apex of the arc

[TheCADWhisperer · Accepted solution]

@ekaj_999 

Did you really really intend this .125 offset (little more than thickness of sheet of paper)

or did you really intend for these faces to be flush?

Examine the Attached file.

[g-andresen]

Hi,

The messages are typical for Prusa Slicer 2.6.0.
Try an older version or set a small BRIM.
Fillets at the lower edge are problematic for 3 D prints.
It is better to use a 45° chamfer there and then let it taper off into a fillet at the top exit.

günther

[ekaj_999]

Those faces were supposed to be flush, I was sure I was creating the sketch for the side tabs on the back face of the main body so I'm a bit confused as to why there was a gap there 😕

Thank you so much for taking the time to revise and attach the project file - I will definitely opt for a similar workflow in future instead of trying to split it into different sections. 😅

Many thanks @g-andresen too for the advice, much appreciated 🙏

[TheCADWhisperer]

@ekaj_999 

Nothing wrong with splitting into different sections. But Combine when done. And of course carefully inspect the final geometry.