Can't create wide finned coil, (like an auger)

[-Nick-]

I'm trying to create a coil for a type of mixer, 200mm diameter, 3 revolutions, 250mm high with a -10 deg taper.  The coil is square sectioned, (2mm), and I have no trouble creating it but I cannot adapt the coil to create wider fins, 10mm at least. 

If I offset the inside face of the coil, after 5mm the geometry fails.

If I try and sweep a profile from the bottom of the coil, (my preference as I can play with the profile shape), either it also fails or I get unpredictable twisting and edges.

Finally, I am suffering numerous crashes when either creating or editing coils, as happened when I was trying to record a screencast for this post.

Help would be appreciated.

[davebYYPCU]

You need the coil, as you have described.

Then sketch the 10mm flange line, connected to the vertex of the coil. (or the flange profile for a solid flange)

then Sweep with Rail and Guide Surface, in the patch area for a surface, like this, (coil is hidden)

Might help....

[-Nick-]

Yes, that did help - using a guide surface.  However, not still not sure why I'm getting all these edges, (radiating outwards), which in your image you seem to have avoided.

[davebYYPCU]

Your visual style is Shaded with Visible Edges, 

I use Shaded.

[-Nick-]

Thanks for your help but I do think there's a problem somewhere with coils.  I've had numerous crashes, (4 or 5 a day), offset fails easily and edges get created where there should be none.  Should I care about the edges? Perhaps not...

[HughesTooling · Accepted solution]

How about making the coil section wider then press pull the top face to make it thinner? This started as a 30mm square section.

Mark

[-Nick-]

Ha ! That actually worked pretty well and I got the shape I wanted.  I didn't get to design a fancy profile but for the moment that's not an issue and maybe it never will be.  Thanks!

[-Nick-]

... spoke too soon.  When you offset the upper surface the offset is actually created at a weird angle so that if you reduce a 25mm section by 23mm, you actually end up with a wedge shaped profile rather than a flat, 2mm thick coil.

To finally get what I wanted I created a 25mm section, copied it to 2mm above itself and used it as the tool to cut the original using the combine tool.

[TrippyLighting]

You could of course reduce the section size to 2mm and use the press-pull tool to move the outer helix to the desired 25 mm width 😉

[HughesTooling]

@TrippyLighting In the first image in the thread you can see press pull fails at around 10mm offset, the odd thing is it works if you enter 23!

One other problem with coil is the section is parallel with the axis not the helix so the 2mm height actually gives a material thickness of 1.98, probably close enough but something to bear in mind. See attached file.

Mark

[HughesTooling · Accepted solution]

Looking at the coils made with press pull the wall sections are not consistent. They vary from about 1.98 to 1.83 so to get an accurate thickness you might want to extract one of the surfaces and thicken, see attached.

Mark

[-Nick-]

Yes, that works, thanks.

I am not qualified or capable of examining the geometry necessary to make this kind of shape, but having spent some time now trying to make my ribbon mixer using the tools available I wonder if the coil command could not be improved? Perhaps this is a little used feature but having again had Fusion crash this morning while trying to edit the temp file you attached, I wonder if it is not a bit buggy.

Thanks for all the input.

[HughesTooling]

The coil tool could definitely be improved but I haven't had any crashes using it, have you sent in the crash reports. I you have I'd start another thread in support about the coil crashes and include the report numbers. It could be a problem with your install.

Mark

[-Nick-]

All my crashes were reported and though it may be my install it only happens with coil, usually when double clicking on the coil event in the timeline to edit an existing event. I will post a separate message if I can reproduce the crash but at the moment it is quite random.

[HughesTooling]

I've been experimenting quite a bit the last few days with this post and another on custom threads and not had a single crash. Are you using a PC or mac?

@PhilProcarioJr has a thread somewhere demonstrating how to make coils in the patch workspace, no use of the coil feature at all. I've attached a sample file, the path in the sweep doesn't even need to be a line if you want to make a coil follow a spline for example.

Mark

[PhilProcarioJr]

@HughesTooling

It was here.

https://forums.autodesk.com/t5/fusion-360-design-validate/easy-way-to-make-a-bent-spring-or-cord/m-p...

[PhilProcarioJr]

@HughesTooling

It's sad that we have to use all these work arounds for broken core tools in Fusion...but hey what do I know... 

[-Nick-]

@HughesTooling

Thanks for bringing that post to my attention, it really helps. (Should have put "Spring" in my original forum searches).  The crashing may well be linked to my setup but why it should be linked to coil, I don't know. 

@PhilProcarioJr

That's opened up a lot of possibilities for me going forward so enormous thanks to you and all the other posters.  (I don't know what I'd do without this forum, seriously).

[PhilProcarioJr]

@-Nick-

I'm happy it is of use to you.

For me these days I need a CAD system that actually works without me jumping through hoops for no reason at all.

The bugs in Fusion along with missing core functionality is just unacceptable. I had high hopes for Fusion, but the last 3 years has shown me it will be a very long time before it will do what I and many others need. 

[TrippyLighting]

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@-Nick- wrote:

(I don't know what I'd do without this forum, seriously).

---

See, this is the difference between now and 15-20 years ago. 15-20 years ago you'd been referred to RTFM

At that time documentation was often readily available and written with wit and humor and often very detailed.

This can still be seen in the Autodesk Alias documentation of which much was written before AD got a hold of Alias.

Nowadays, there is not in-depth documentation, which takes the "fun" out of responding to thread s like this, because 

even that which is there is almost entirely non-technical rarely explains concepts and is aimed almost exclusively at beginning CAD users.