topic Re: Tapered Extrude Problem in Fusion Design, Validate & Document Forum

Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 01:46:49 GMT

I've probably been working on this extrude problem for several hours now. I'm starting to worry I'm not going to come up with a valid tapered extrude. I know imported dxf files can be problematic in Fusion 360 but I just dont' have the luxury of this information coming to me from Fusion 360 natively. I need to put a 4.36 degree tapered extrude on the sides of the trench that makes the images. Can anyone tell me what I'm doing wrong. I know if one tapered wall face is "consumed" by another before it reaches the floor of the trench it will cause an invalid operation but I can't see where this is happening here. I can get the extrude to work with a taper of 3 degrees but 4.36 is not working. I'm burning a lot of brain cells on this one. The outline was originally made in Rhino. I've take the dxf export and opened it in Autocad to sort out some issues. I've tried converting the polyline to arcs. The answer might lies in one of these operations but nothing I've tried so far seems to make it produce. Of note: When I have excluded the bear from the extrude operation it works! Any help is greatly appreciated.

https://a360.co/2Ppjq5e

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 09:08:57 GMT

Hi,

I converted the DXF to Bezier and pasted it back in.
I only used the panel with the extrusion 0.325.

günther

Re: Tapered Extrude Problem

barry9UDQ6 — Mon, 26 Apr 2021 09:18:26 GMT

The command that you need to use is modify-draft.

But because of the complexity of your imported sketch it has created countless faces, so I think you will struggle too much with the command.

I would try a couple of things first. Instead of importing the sketch in from Rhino, rather extrude the profile as a surface in Rhino, and then open it directly in Fusion. Hopefully this will give you a smoother profile.

Or use your imported sketch as a reference only and re-draw the profile in Fusion. This might take you 1/2 hour. But it will save you much time and frustration when it comes to using the profile and you will get a much better end result.

Rhinos interpretation of DXFs when it exports them is in my opinion very poor.

Re: Tapered Extrude Problem

HughesTooling — Mon, 26 Apr 2021 10:45:11 GMT

These setting will give you quite good exports from Rhino as a DXF. These setting seem to export splines quite well , Note the setting to explode polycurves and split curves at kinks. Can you share the original Rhino file? You'll need to ZIP it to upload to this forum.

Mark

Re: Tapered Extrude Problem

barry9UDQ6 — Mon, 26 Apr 2021 12:58:34 GMT

I am going to try these settings for myself!

I have had problems in the past with ticking the maximum angle box, it caused my gentle curves to deviate quite badly from the original (and it was for cutfiles)

And whenever I have ticked the explode polycurves box my profiles have come through as open.

But I must have had another checkbox wrong somewhere.

Re: Tapered Extrude Problem

HughesTooling — Mon, 26 Apr 2021 14:22:56 GMT

Not sure the curve tessellation options do anything if you have Simplify unchecked. I found I needed explode polycurves checked because a mix of lines, arcs and splines in one curve caused problems, think it was multi spline curves that caused the most problems.

Mark

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 15:58:36 GMT

Hi,

just something to illustrate

günther

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 16:15:21 GMT

This refinement to the export characteristics of Rhino looks really promising. I used your settings and brought in my image. The sketch information looks really clean and it appears to be a closed profile. However, I got the attached warning when I imported it and can't seem to generate an extrude from the result. Any thoughts are appreciated.

The file link is here: https://a360.co/3ev5LlH

I have also attached a simplified Rhino file. You will notice there are two closely spaced and parallel polylines that indicated the top and the bottom of the drafted surface. As per our discussion, I am working with the outer one and trying to create a tapered extruded void. Strangely, the polylines in the other rows above have functioned fine. Thank you for all your help. Invaluable.

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 16:17:58 GMT

I'm not familiar with the convert-to-bezier process in Fusion but this does job a memory I have of first importing a dxf sketch and then converting it to something else before performing an extrude. Would you mind elaborating?

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 16:28:23 GMT

Hi,

Since a conversion to Beziér is not possible in Fusion, I did it in V-Carve pro.
The result can be found in the attached file above.
I just want to show that extruding, especially with taper, depends on a suitable profile.
How and with which application this is achieved is another story.

günther

Re: Tapered Extrude Problem

HughesTooling — Mon, 26 Apr 2021 17:27:22 GMT

The original curves don't look too bad but the offset ones are not good (these are the ones giving the error in Fusion). This is always a problem with offsetting splines especially in a polly curve.

The exturde from the original curves look a lot better using the export setting I show above. It still doesn't work with a taper though. What do you need the taper for. Are you going to machine the part, if so does it actually need the taper?

Re: Tapered Extrude Problem

jodom4 — Mon, 26 Apr 2021 17:42:41 GMT

mcobb, are you still using that spreadsheet to make your dihedral angles, Mike? 😉

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 19:03:36 GMT

I could geekily talk your ear off about that one. 🙂 ... but no, I am not using a spreadsheet for dihedral angles these days. 🙂

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 19:11:36 GMT

Hi,

I would just like to point out that the extrusion including the desired taper in the file attached above works.

günther

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 19:12:30 GMT

The mill produced will be used to cast a polyurethane rubber mold for some concrete work. See attached images of a sample prototype.

Yes, the offset profile is problematic for extrudes. I'm not planning on using that for any extrude operations. Instead, this inner line will be the path for a trace command during manufacturing. I am using a tapered bit to perform the milling around the perimeter of all the pockets. Right now, I am simply trying to define the model and this one extrude command is being problematic.

Looks like you were able to accomplish an extrude command with that problematic polyline. That is great! I wasn't able to accomplish even that. I wonder what you did differently than me? Thank you for all the help thus far.

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 19:14:28 GMT

!?!? I'm sorry, forgive my ignorance, which file are you referring to? Something you posted or a file that I posted?

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 19:31:16 GMT

Hi,

@mcobb wrote:
!?!? I'm sorry, forgive my ignorance, which file are you referring to? Something you posted or a file that I posted?

#2 > „Part_NEW“ Tested < 6.3deg

günther

Re: Tapered Extrude Problem

mcobb — Mon, 26 Apr 2021 19:54:30 GMT

I see. Thank you. The taper is actually negative 4.36. I should have been clearer. For some reason he the taper reduces the width of the channel, this still does not work. Thank you for trying. So close. 😞

Re: Tapered Extrude Problem

g-andresen — Mon, 26 Apr 2021 20:13:45 GMT

Hi,

@mcobb wrote:
I see. Thank you. The taper is actually negative 4.36. I should have been clearer. For some reason he the taper reduces the width of the channel, this still does not work. Thank you for trying. So close. 😞

Then position the sketch so that you can use a positive angle.

günther

Re: Tapered Extrude Problem

HughesTooling — Mon, 26 Apr 2021 20:55:34 GMT

Looking at what you're doing you don't need to model the tapered extrude. If you use 2d contoured and setup a cutter with the correct angle the offset for the taper will be calculated for each depth. You could even use a parallel cutter, I seem to remember 2d pocket and contour have options for taper pocket if you use multiple depths.

Mark