slicing problem with fusion 360 generated object

[Sammysuj 0]

I am a real beginner, so apologise in advance if I am doing something so totally obviously wrong to you experts out there, but I have been trying for months, with hours and hours a week

to solve this issue without any progress,(I hate to add up the wasted time)

So pleeeeease please someone out there take pity and help me out. Tell me what I am doing wrong or better still help me fix it.

I am using a combination of Autocad 2017, Fusion 360 and Meshmixer. started with an imported scan of a very thin walled hollow object.  Drew up a base ring for it to sit on and in inserted into fusion360,  modded the ring extruding sections sections to create my required base with fixing lugs etc. The mesh was then "embedded" into the ring. 

Everything looks fine, when I rotate the object about in all planes I see exactly what I want. perfect -so I thought last Autumn !

when I highlight the entire object and create an stl file for printing -again all seems ok

Using Cura 4.4 I can then open the file, land it on the base, again all looks great, even viewing through the build plate from underneath again all looks fine.

However as soon as it is sliced (again it performs this perfectly) then when I preview or even create the 3D print it this is where the problem shows up.

 

it fills a 5 layer thick sheet right across the entire open base at the level where the "mesh joins the solid ring into which it is embedded.

I have tried, combine in the Mesh tools of fusion360,  even converted the Brep to a mesh and then combined, stitched, played around in Meshmixer, just about every conceivable way I can think of, to stop the Cura slicing stage adding this infill layer across the open neck of the mesh where it joins the extruded ring creation.

 

I know I am obviously doing something very wrong at some stage but I cannot find a solution.

Can anyone please please tell me how to solve this ?

 

Experiment1 v1.obj

[owen 19]

Hi

It sounds like you have an error/hole in your obj file. Possibly get a program that can show where it is and/or patch it or start again with a simple base maybe a mm higher than your current base. Once you can get that to slice than cut out most of that base and create your current base again. Just post back if any of this is unclear and if you really get stuck please send the fusion 360 file or share it.

[Torgeir 280]

Hi Sammysuj,

 

Welcome in here,

I just imported your model into Fusion 360, then sent the stl file to Cura 4.3.0 (the version I'm using).

I could not see any big problem with your model, but could see the 3 or 4 extra layer at the bottom of the upper part of your model. As I've also use Simplify 3D, I also imported the model in here. Simplify 3D also indicate 3 or 4 layer at the upper part of your model, but it's also indicate there is a gap between the upper and the base of your model. I'll assume that those to parts is not properly joined together as one part in Fusion 360. There is also some issues in the upper "curvature" according to S3d monitor.

 

Just my thoughts.

Thanks

 

Torgeir

 

[Sammysuj 0]

Thanks for your comments, I believe you are correct in that you say the upper "Mesh created part" and the lower Fusion created "Base mounting Ring" as I call it are not fused fully into one object.

Hence when slicing cura sees the "Mesh created" upper section of my model as an open ended mesh and closes it across .

I have tried so many ways of forcing them to join, combine, etc, including trying to make the lower ring sketches into a mesh and stitching the meshes etc but all without success.

What I want is one complete model that is totally hollow , rather like Top Hat from Alice in wonderland if you understand my meaning.

Any idea's would be much appreciated. 

 

Sammysuj

[Sammysuj 0]

On 1/26/2020 at 8:37 PM, owen said:

Hi

It sounds like you have an error/hole in your obj file. Possibly get a program that can show where it is and/or patch it or start again with a simple base maybe a mm higher than your current base. Once you can get that to slice than cut out most of that base and create your current base again. Just post back if any of this is unclear and if you really get stuck please send the fusion 360 file or share it.

Hi Owen,

it appears to be a problem with the upper part of my model which is an open bottomed Mesh as this is where it closes across.

the bottom "ring section prints ok on its own, but if I try to print the upper section on its own it fills across the open lower neck so to speak. 

I thought I had uploaded the fusion file in my post the Experiment1 v1.obj  attachment after my 3 images

(It is my very first post ever so sorry if I didn't do that correctly ? )

 

[gr5 2,266]

Is the mesh solid?  Or is it infinitely thin?  You have to give it a thickness.  I recommend at least 1mm thick.

[Sammysuj 0]

Hi, the mesh is infinitely thin, when you say give it thickness, do you mean by creating a 1 mm offset in the fusion stage - ? I did try that at some point but still couldn’t get the ashes to join properly to the “drawn ring” below it- 

any idea how I make that bit happen 

thanks for your input by the way 

[gr5 2,266]

Yes exactly.  If you make it infinitely thin cura really shouldn't be printing it at all as infinitely thin is the same as nothing at all.  But it's seeing that the mesh goes all the way around and assumes it's a solid.  As cura is meant to print solids.

 

[gr5 2,266]

Another option might be to make it "voronoi" for a more airy look.  I don't know fusion 360 so I don't know if this is a built in feature.