Creating a spiral tube...

[SimonPlatten]

I want to create a spiral tube that starts off with a diameter of for example 20mm then decreases to a diameter of 8mm.   I intend to 3D print this and I want it to be a spiral pipe work that liquid can flow through.  I've create a solid object using the coil feature, however I don't know if I can create a pipe that starts off as one diameter then reduces to another diameter, also its solid, I've tried using shell on the coil but it doesn't have the effect I desire.

Can anyone help ?

[Warmingup1953 · Accepted solution]

Here's my go it.

[SimonPlatten]

Thank you, I saved your file, edited and reviewed actions, I see now using Loft.

[SimonPlatten]

How do you create the spiral on the sketch ?

[TheCADWhisperer]

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@SimonPlatten wrote:

How do you create the spiral on the sketch ?

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All in the Timeline.

Unfortunately it is not correct as the circular profile is not perpendicular to the path.

[Warmingup1953]

I used the Coil function (with a couple of false starts!).

I think CADWhisperer is correct in his criticism re perpendicularity but that may not matter for your use. 

[HughesTooling]

Here's a version with the end faces perpendicular to the helix. I used a pipe around the coil to give me faces to sketch on, could have used plane along path as another option. Only used the pipe because I thought you could set start and end diameters but Fusion can't do that (another program I use can). 

See attached file. Was going to just shell the first loft but Fusion created some strange artefact when I tried that. Could be because the seam on the loft is twisted?

[SimonPlatten]

Thank you, looking at the file and timeline it starts off with CoilPrimitive1 then Pipe1, Sketch3, Sketch4, Loft1 and finally Loft2.

I've looked at the file several times and I don't really understand how the spiral appears between the two sketches.

I've added a screen shot showing the entry sketch and the exit sketch where the entry is from the top and the exit is 90 degrees and 300mm below.  I am trying to create a spiral pipe that gets narrower as it does down, starting with a 20mm inner diameter and exiting with a 8mm inner diameter.

I'm hoping that this design with help to increase water pressure when water is passes through it from above ?

[Warmingup1953]

This is Loft 1

[SimonPlatten]

Thank you, but can you please fill in the blanks with some instructions suitable for me to follow step by step ?

[Warmingup1953]

[SimonPlatten]

Thank you, but the diagram alone doesn't really help me.

[Warmingup1953]

Just for clarity.

[SimonPlatten]

What does that clarify ?

[Warmingup1953]

Mmmm. OK I'm unsure of the level you are at with Fusion 360 learning journey but here I go....The Yellow body is the Coil. The Vertix of that body is used as a Centreline path. The Pipe (Solid Red) gives you a planar surface at either end...On onbe planar surface you create a sketch of the proposed large end's inside and outside diameters concentric with the spiral path you'll use for the loft (Yellow) You then Loft a solid Outside spiral of diminishing diameter and ditto for the inside then you Combine cut those two solid spiral diminishing solids to create the spiral tube of your desires!

[SimonPlatten]

 

Thank you, assume I know nothing and then you can't go far wrong.  I've been using Fusion 360 for a while, but not constantly, now and then when I get time.  Attached is another 3 sketches showing the top entry hole of the pipe, rotate 90 degrees then spiral down to the exit point at the bottom.

[Warmingup1953]

Well that can be done as Extrudes and revolves if I understand you needs

[SimonPlatten]

Thank you, getting there slowly...

[SimonPlatten]

I'm struggling to see how I create the sketch that creates the line that will be used to follow and create the spiral ?

[HughesTooling]

If you're just talking about the spiral, use the edge of the coil. You should use the edge because a surface edge is more accurate than a sketch.