Errors with Draft and Sweep on Curved Path

[tedbradley314]

Hi folks, 

I'm extruding clay through a profile/die. I want the extrusion die to have a draft like a funnel so it compresses the clay into the final shape as it passes through the die. 

I'm having a tough time modeling the funnel/draft. I first tried to create a draft feature and got the attached error. Then created my own draft profile and tried to sweep it along the profile path but got errors doing that as well. A bit of help would be very much appreciated. 

Thanks,

Ted

[etfrench · Accepted solution]

Here are a couple of ways you can work around the sweep limitations:

1: Do the sweep in small segments.  You'll still need to determine what to do with the acute angles where the sweep will intersect.  https://knowledge.autodesk.com/community/screencast/3b848b21-1beb-40f2-9244-10b43f96341c

2: Use the loft command.  You'll need to adjust the profile around the same acute angles: https://knowledge.autodesk.com/community/screencast/2b1c0162-a38a-4ef8-813a-6fc0dd915c6c

Here's the loft method:

[HughesTooling]

Could you keep the corners sharp then add fillets (constant radius rather than conical) after the draft? Only problem are the 2 splines, could they be fillets? If not I'll leave it up to you to create something you could sweep or loft. See attached file.

Mark

[tedbradley314]

Thanks @HughesTooling.

Fillets seem to only work between two straight lines. I wasn't able to use them between a straight line and a spline. 

Thanks @etfrench. 

I tried loft and it gave me a perfect result. 

[HughesTooling]

@tedbradley314 Do you really need the splines? It becomes a lot easier if all corners are filleted. Actually it's only internal corners that are a problem. If you can use constant radius fillets, uncheck tangen selection and only select the faces, not the fillets. Screencast shows what I mean, don't know if this might be useful if you make a lot of these.

Mark

[HughesTooling · Accepted solution]

---

@tedbradley314 wrote:

Thanks @HughesTooling.

Fillets seem to only work between two straight lines. I wasn't able to use them between a straight line and a spline. 

---

Reading this again I see the problem, your part is a good example of why you should not fillet the sketch but fillet the body. In the first file I attached I created the body with no fillets, added draft then added the fillets. A lot more simple and quicker than filleting sketches.

First unfilleted body.

Then add draft then fillet.

Mark

[tedbradley314]

Thanks Mark! That looks like a great solution. Namely:

• removing fillets from the draft and adding them to the body
• creating draft by selecting individual flat faces rather than all faces including the fillets

I wish I would have seen that before I poured a couple hours into getting the loft to work. The challenge with the loft is that it doesn't know what reference points to line up when creating a face between the two profiles. So I had to add a ton of rails which was very time consuming, since every rail required it's only sketch on a unique sketch plane. But it did get a good result in the end.