Help producing a semilunar shape

[ysnyder]

I was having trouble reproducing this shape and structure. The top of it has a complicated shape and I am having trouble wrapping my head around sweeps and lofts that can produce this structure. I have attached my .ipt and the image of the structure I am reproducing. As you can see there is a slope that is hard to model along with the circular structure. I would appreciate any recommendations you can offer. 

[Anonymous]

Hi! let me take a look at the part for a while and I'll see what I can do.

[Anonymous]

Is this the shape that you are looking for? If it is I'd suggest taking a look at how I did it using a loft and some variable fillets. I don't think that you can get a loft to close to a single point, so my guess is that the sides would probably have to have a little bit of height added to them.

[ysnyder]

I cannot seem to open the file. I am using Inventor Pro 2016, I assume you're using a newer version?  

[Anonymous · Accepted solution]

I am using inventor 2018, I will try to show you the way that I performed the feature.

This is what it looks like.

Essentially what I did was use 2 sketches to create a path for a loft, which seemed to be what you were trying to do. Make one sketch in the middle of the individual wedge surface to whatever height and curvature you'd like. Make sure it is a closed loop of course otherwise it won't work. Create the second sketch on the side of the indentation that runs through the shape. Make a third sketch on the flat top and put an arc in the gap between the 1st sketch and the second, this will be the path for the loft. 

It should look something like this in the preview.

After this, create a plane "midplane between two planes" and use the indentation referenced earlier to create a plane that runs parallel to the flat side of the loft. Mirror the loft over this plane and then use a circular pattern to duplicate the features to the other 2/3 of the part.

It should look like this.

Once that has been done, you can hide the workplane if you'd like. The next stage would be to add the fillets that are present in the 3 points that converge near the center of this part. Depending on what their radius may effect the next stage but mine were set to 0.05 in (.127 mm). 

Another reference just in case my explaining is bad. 

Lastly, we need to smooth out the curve on the feature in question, because yours had a fluent flow and not a defined center line. For this I used a variable fillet. Depending on what your radius for the previous fillet was will probably determine what the best values for your fillet will be. The key is to try and make the line more flat because the fillet will try to overlap the edge. 

I would suggest using 3 points (start, end, custom at .5). This should make the transition smooth. Again, the values used will be different depending on what your first fillet was and how much curve you'd like to add. Once done with that though, create another circular pattern to apply the fillet to the other 2 sections. That should leave you with a finished model. 

Add the hole if it is a part of your feature and then you should be all set mate.