Turbine Casing Modelling

[cess9]

Hey there!, I am trying to model this casing in inventor. Any advice? do you have any procedure?

[James_Willo]

Hi, why do you need to model it if you already have it?

[cess9]

Hi James, it was made in another software, and we are migrating to Inventor, so I need have the native file for future changes.

[James_Willo]

If you need a parametric model, you should be able to model it exactly the same way as you did in the other software.
If you just need to make tweaks you can try using Direct Edit to manipulate the geometry. 

[cess9]

Thanks James, but I did not model it in the other software, that's why I am asking for advice. Maybe I was not clear enough, sorry for that. I just need to replicate this piece in inventor, it is quite complex to do it for normal ways.

[James_Willo]

You can use the step as a guide and build it up feature by feature, see this video. 

[piotrekdoro94]

What software have been used to make the cast and do you have access to it? It might be worth it to install it if you have an executable lying around or to try and download a time-limited or legacy version if it is available in order to retrieve all the features.

When it comes to modelling complex parts for metal casting (I'm assuming that's how the part will be manufactured) I would recommend trying a multi-bodied workflow. My general advice is:

• identify how will the part be molded/unmolded. Pay attention so that all surfaces are tapered in a correct direction. There should be no surfaces parallel to the direction in which you will slot in your model and cores and absolutely no overhangs
• make sure you round all the sharp edges or the molten metal might not fill them properly,
• the model you have access to might or might not be scaled to account for shrinkage of solidifying metal, so take that into account,
• try to model the cast part in its raw state first (the way it will look right after unmolding), apply all the features that are the result of machining after you are done with your raw cast,
• simplify your model into several bodies. You want them to intersect. Taper them properly, subtract them, delete leftover pieces of solids (use command in the image below), add them to create a single solid and apply fillets in this order

• you might have to use some lofts. If they get too complex you can divide them into several simpler profiles. Use guide rails generously, remember to check if your loft features didn't result in too thin/thick walls or you will end up with some holes/internal cavities. Remember that with lofts you can change boundary condition to tangent to avoid having to apply additonal fillets in places where new loft profiles are situated. 

 

[JDMather]

@cess9 

Can you Attach the *.ipt file of your attempt to remodel the geometry in Inventor?

I would model as a solid.

Then Shell

Finally, add the machined features.

This is not a beginner endeavor but at the same time the geometry is not overly complex.

[johnsonshiue]

Hi! To remaster the part, I would remove unnecessary detail first. This casting part has a lot of filleted edges. I would use Delete Face/Heal to remove the blends. After that, the body should be much more simplified. The dimensions can be measured more easily.

If you are moving from another CAD tool to Inventor, consider using GoToInventor (https://www.iti-global.com/interoperability-products/gotoinventor/) by ITI, an Autodesk partner specializing in translation services.

Many thanks!

[cess9]

James, this a good approach thank you, the thing gets a little bit tricky once you have to model the oulet pipe which has some special features. I was doing a different approach but still is not a good clean model since has too many operations that can be easily simplified.

[cess9]

Yes, indeed. I was following somehow that workflow.  I am attaching the model as I currently have. 

Thanks for your help!

[JDMather]

@cess9 

One thing I would probably do differently (if possible) is not add any of the Fillet features until near the end.  Certainly try to avoid dependencies to the Fillets.

Another tip is to add the Shell early, and then drag the EOP above Shell, create a feature and drag the EOP back down to make sure nothing fails.  Keep repeating this process (if possible) until all shelled features are completed. Then go on to the remaining features.

[JDMather]

@cess9 

I think you are getting this figured out - but remember, the start is from a casting with machined features.

So for example, this hole do as tapered to get the correct Shell and than after all is done add the "drilled" cylindrical hole feature.

[JDMather]

@cess9 

I have also found that sometimes overbuilding the geometry to as-cast condition helps in getting the fillets.

I saw only one fillet where this might be a useful technique.  Then cut away the excess cast material - just like on the shop floor.