Hard Part- Help Experts

[bespel]

Hi to all,

i have problem with this.

I have no more infos but the attached drawing.

I have attached too the part until the level i have reached with all my force.

Thank in advance for the help.

[salariua · Accepted solution]

I am no expert but the 4.03 dimension seems wrong (ADS1 file attached) and I think it should be 3.992 (ADS2 file attached)

[bespel]

Hi Adrian,

you are very kind. Thank you for your help.

I was going mad trying with sheet metal... with no success.

Thank you!  The wrong dimension... i don't know..probably you are right!

Thank you again!

Bes

[bespel]

Hi Adrian,

what are the consideration that make you  think that there is an error and that it's better that other number?

Just to learn 🙂

[salariua]

the 4.03 dimension makes the coil sit wrong. Point one is not on face and point two not coincident with exit edge. That's why I have the delete face operation at the end of ADS1 file.

If you delete the dimension and constraint point one on face edge you end up wit 3.992 but I am no expert.

[bespel]

thank you Adrian!

[IgorMir · Accepted solution]

Hi Bespel,

Here is what I can offer. IV 2010 fiile. End tips need some more work on it but overall it should give you some ideas.

Cheers,

Igor.

[JDMather]

Looks like the actual geometry is the typical cylindrical cam problem posted here many times over the years.

To model correctly - you have to consider the actual manufacturing process.

Can you provide information on your manufacturing process?

I am going to assume this is not from rolled sheet welded to the hub, (but if it is - you should let us know).

.....well I was going to continue... but decided I need to know answer to above question.

[IgorMir]

Hi JD

I couldn't see any sheet metal part in the sketch provided by OP. It looks like the machined part all together. While we are on the topic - in the model I have provided I couldn't get the Sweep to do a clean cut at the tip. It leaves a small step over there. Seems like Sweep doesn't want to follow the Rail properly. Or am I missing something obvious here?

Thanks,

Igor.

[JDMather]

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@IgorMir wrote:

Hi JD

I couldn't see any sheet metal part in the sketch provided by OP. It looks like the machined part all together.

Igor. 

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That is what I see in the drawing as well.  But I am thinking the drawing might be a simplification of the actual part - based on some very similar designs I made more than 20 years ago when I was still working out on the shop floor.  I will go ahead and proceed as though it was totally machined from bar stock.

[JDMather]

Hopefully this is going to make some sense.

First, I think the supplied drawing is an approximation on some of the dimensions based on old 2D drawing techniques and hand measurements rather than geometry.

Second, I think the true profile depends on the manufacturing process as I will try to demonstrate.

I am going to assume the true profile is a Helix cut with the side of a Ø5mm end mill (and then perhap ground finished). 

The motion of the cutter is essentially a cylindrical cam follower - the cut profile is dependent on the follower diameter (the end mill in this case).

With Sketch2 visible - examine the 2 sketch points from the Right side view - I think these are approximations in the drawing.

Hide Sketch2.

Unsuppress Thicken1 - the surface representing the centerline path of a Ø5mm cutter.  Now this could be moved, but the point to observe - is that the actual cut profile will be dependent on the cutter diameter, whatever the position of the centerline of travel.

At least that is the way I see it.

[bespel]

Hi, it is machined from bar. I don't know much but this.

Your points are very interesting and correct, thank you for your help, your time, the parts you have modelled  and your experience.

Thank you all.

Now i will study your solutions!

[JDMather · Accepted solution]

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@bespel wrote:

Now i will study your solutions!

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I just realized that I had one of the dimensions as Ø30 where it was supposed to be Ø32.

[bespel]

Thank you for the accuracy!

[IgorMir]

Ni Bespel,

Here is an updated part with the end tips fixed.  There was a small problem with the Sketch6 for the Sweep1.

Cheers,

Igor.

[rmerlob]

I've always thought that we should be able to parametrically sketch directly on curved surfaces, at least cilinders. Something along the lines as a 3D sketch where all lines and points are constrained to a surface.

Or is that too much to ask to any CAD software?

Anyways i'll give it a try and see what i come up with.

[JDMather]

Like 3D sketch Equation Curves?

[rmerlob]

No what I had in mind is more like drawing a line/circle/spline in the 3D sketch enviroment but when you click the points it actually projects them through the view and onto the surface.

In this mode of course when you pick two points for a line instead of an actual line you would be drawing a spiral, I know you can do this with other commands but what I have in mind is something a bit more intuitive that actually feels like drawing on a rolled sheet of paper or something like that.