cut Helical groove

[mmistry]

Can someone help I am trying to cut helical groove as per drawing.  groove design is as per section (A-A) but an angle.  please see attached drawing. 

[LT.Rusty]

Coil feature set to subtract will probably be your best bet.  Do one groove of the three, then a circular pattern to make the rest.

Post the .IPT file of what you've done so far, we'll take a look and see exactly where you need help.

[mmistry]

as requested see attached 2 files

[LT.Rusty]

Looks like you already got it, in your 826-A file?

[JDMather]

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@LT.Rusty wrote:

Looks like you already got it, in your 826-A file?

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Doesn't look correct to me.

On one like this you have to consider how the cutting tool will move along the path.

I don't have time to take a close look at this one, but if this is the problem I think it is, there is more involved here in getting it correct.

[LT.Rusty]

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@Anonymous wrote:

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@LT.Rusty wrote:

Looks like you already got it, in your 826-A file?

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Doesn't look correct to me.

On one like this you have to consider how the cutting tool will move along the path.

I don't have time to take a close look at this one, but if this is the problem I think it is, there is more involved here in getting it correct.

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Ah, yeah, I see what you mean.

Hm.  I have a few minutes to play with here ... unfortunately I think the OP has a version <2013, so he probably won't be able to open anything I might come up with.

[JDMather]

As you experiment - notice that the center of the arc appears to be below the edge of the cylinder.

I think it will take a Coil surface path, the profile perp to the path and a Sweep with the Guide Surface (cylinder) option.

I would also question the function of the part as it might be simplified in the old 2D drawing and not representative of the real part.

Ref see - http://forums.autodesk.com/t5/Inventor-General/Sweep-Cut-a-solid/td-p/3251382

[LT.Rusty · Accepted solution]

Yeah, there's some issues with the drawing, and I really question how this could even work.

If you look carefully, the sketch profile is not actually normal to the path of the sweep.  Another thing - and one that took me a good few minutes to catch on to - is that the section plane is not 39.53 degrees of vertical - it's 39° 56' off vertical, which is actually 39.93°.

Also, the cross section simply cannot have that geometry.  The outside contour of the part along that section is not even remotely close to being a straight line, and the edges of the groove cannot be at 90° to something that is not a straight line.  Further, a true round profile at the bottom of the contour will not provide the profile shown in the end-on view of the part.  (See your 826-A file, or my scroll 826-rusty 3.0.ipt for examples of this.)

That said ... I was able to fudge some dimensions that aren't provided in the drawing to get something that kinda-sorta approximates the shape of the profile shown in section a-a, but with some caveats.  The bottom of it is not a half-round, and it doesn't have straight sides.  It's a sort of half-ellipse, BUT it does give the bottom profile that's shown in the drawing, more or less.  (I don't have full arc dimensions there, so I guessed on some things.)

See if you can post more details of the original part drawing.  There's really not enough info there to do more than guess.  The pitch of the helix, for example, is not specified.  You used .3 turns in 9.53mm in your file, I did 1/3 in 3/8" for mine.  (I'm guessing, but I suspect that is what the actual number would be.)

Anyway, here's the files I've generated.  I'm not positive you'll be able to open them though ... I think you're using something earlier than Inventor 2013 ...

[mmistry]

Thank you Rusty I will have look at it in the morning and send you reply back tomorrow

[mmistry]

thank you guys I cannot ope the files but I have down loaded on my PC, the Scroll 826-Rusty looks similar to what I created. i know the 2D drawing is wrong therefore i am attaching a picture of the scroll.  it is similar to above and my 'A'.ipt.  I have asked our IT for a upgrade version untill then thank you for your help. 

[JDMather]

That doesn't even look like the same part?

Do you have any manufacturing information - are you currently manufacturing the part?

I have often seen cases where the CNC code has been generating parts for years - but this was all figured out on the shop floor and the documentation doesn't match what is happening on the shop floor.  Getting that information is the key to correctly documenting the part.

[mmistry]

we do not manufacture these in-house therefore i will have try and requested the manufactuing data and come to you as soon as possible.  I did try your suggestion of (http://forums.autodesk.com/t5/Inventor-General/Sweep-Cut-a-solid/td-p/3251382), with simlar result to Rusty & Rusty-A. Twicking with Helical options see the result attahed.  Thanks again.

[mmistry · Accepted solution]

I have asked our supplier for the cnc program but they have refused.

[Mark.Downes]

Hi mmistry,

I had a quick look at this, I modeled the part as per the first drawing on your post and got pretty much the same as LT.Rusty when I overlaid them in an assembly.

Ok, that’s not how the photo looks? The angle 39.933° (40° for ease of explanation) is taken from plum vertical. It would suggest from the photo the part is made closer to 60° (if you tweek the sketch plane angle).

Could be the part is made to one spec and your drawing is an old issue.

Cheers

Mark

Inventor 2014

[mmistry · Accepted solution]

Looks very good like the component Mark, thank you but i cannot open it as i am on version 2012,  I am getting an upgrade soon.  thanks again to all for you valuable and expert input.

[LT.Rusty · Accepted solution]

Okay, now a few more things make sense. 

Looking at the picture of your actual finished part, it looks like the profile shown in section a-a of your drawing is probably pretty close to reality, if you ignore the shape they show for the outside profile of the part.  It probably is actually a half-round of R0.156" (or so) with straight-ish sides.

I wonder why they'd show something different in the plan view?

[mmistry]

I don't know as you and others have said the 2D drawing is drawn wrong. Thank you once again. I will have ago when I have a look at how you have done it. We have some more variety of scrolls which will need updating.

Best regards,
Manny Mistry / Project Engineer / Tyco Fire Protection Products
Tel: +44 (0) 161 477 1886 / Fax: +44 (0) 161 474 0928
Unit A3-A5, Stockport Trading Estate, Yew Street / Stockport / Cheshire / SK4 2JW / United Kingdom
mmistry@tyco-bspd.com / www.tfppemea.com
Tyco Fire Products Manufacturing Ltd. Registered in England No. 1841522. Registered Office Security House, The Summit, Hanworth Road, Sunbury-on-Thames, Middlesex, TW16 5DB
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[mmistry · Accepted solution]

cracked it thank you Mr Rusty & Mather for your help

[LT.Rusty]

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@Anonymous wrote:
cracked it thank you Mr Rusty & Mather for your help

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Congratulations!  Now let's see how you did it.  🙂

[mmistry]

see attached.