Inventor General Discussion

Inventor General Discussion

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Active Member
cmanzo1
Posts: 8
Registered: ‎07-24-2013
Message 1 of 9 (248 Views)

re: shelling an object on the outside

248 Views, 8 Replies
12-19-2013 01:55 PM

Hello All,

 

I am trying to shell this object (a smart phone case) on the OUTSIDE by 1.8mm. It is giving me an error message with one vertex too small (in the corner).   I have gone down to .05mm to reduce the thickness just to see if it will shell at all, and it does not. Any thoughts? I finally got shapes to sweep here to make the object the correct shape and really need the actual object to be a shell 1.8mm larger than this current body. 

 

Inventor 14pro

 

Thanks much,

 

Christopher

Mentor
BarryZA
Posts: 199
Registered: ‎08-27-2012
Message 2 of 9 (215 Views)

Re: re: shelling an object on the outside

12-20-2013 02:11 AM in reply to: cmanzo1

I just learned something - didn't know you could shell to the outside!

 

Have you tried working with surface tools instead and offsetting the surface?

Or maybe derive as a percentage, just throwing ideas around.

 

I'm still on 2013, so I can't open your file I'm afraid.

Active Member
cmanzo1
Posts: 8
Registered: ‎07-24-2013
Message 3 of 9 (212 Views)

Re: re: shelling an object on the outside

12-20-2013 02:14 AM in reply to: cmanzo1

Found it - split off corner (the offending part) first, then shelled each separately.  Combine back and wha la, a complete shell.  C

Employee
wilkhui
Posts: 98
Registered: ‎06-28-2012
Message 4 of 9 (199 Views)

Re: re: shelling an object on the outside

12-20-2013 03:16 AM in reply to: cmanzo1

Hi Christopher,

 

It's good to hear that you found a workaround but there are some underlying sketch issues which may cause you downstream problems, such as what you're experiencing with the shell failure.

 

For instance, if I look at Sketch6 I can see that it hasn't been constrained because of the "62 dimensions needed" notification in the bottom bar:

 

Sketch6.JPG

 

Further, the sketch has multiple lines that are close to each other, which can introduce unpredictable behaviour:

 

multiple_lines.png

 

I'd like to draw your attention to JD Mather's 60 Autodesk Inventor tips document, in particular pages 5-12.

 

I'll work on your part and see if I can get the desired shell to work if the sketches are fully constrained and the duplicate lines removed but in the meantime I hope that JD Mather's tips prove useful.

 

Best wishes,

Indy



Inderjeet Wilkhu
SQA Engineer
Autodesk ShapeManager
Design, Lifecycle and Simulation
Autodesk, Inc.

Employee
wilkhui
Posts: 98
Registered: ‎06-28-2012
Message 5 of 9 (168 Views)

Re: re: shelling an object on the outside

12-20-2013 06:56 AM in reply to: cmanzo1

Hi Christopher,

 

I couldn't extract enough information about your required dimensions for the phone case so I've created a similar example made with fewer features, hopefully it illustrates what I meant in my previous post. I could have avoided Combine1 by changing the workflow a bit, it just goes to show that there is always room for improvement..!

 

case_example_iw.JPG

 

Thanks,

Indy



Inderjeet Wilkhu
SQA Engineer
Autodesk ShapeManager
Design, Lifecycle and Simulation
Autodesk, Inc.

Active Member
cmanzo1
Posts: 8
Registered: ‎07-24-2013
Message 6 of 9 (162 Views)

Re: re: shelling an object on the outside

12-20-2013 07:02 AM in reply to: wilkhui

Thanks Indy - I got it to shell by breaking off the corner and working each piece seperately.  What is 'constrained'?  I've seen this, but have no idea what it is/ does.  

 

Cheers,

 

C

Employee
wilkhui
Posts: 98
Registered: ‎06-28-2012
Message 7 of 9 (152 Views)

Re: re: shelling an object on the outside

12-20-2013 07:21 AM in reply to: cmanzo1

No problem - constraints and dimensions allow you to define sketches using conditions (perpendicular, parallel, etc.) and measurements (lengths, angles, etc.) in a similar way to what you would see in technical drawings.

 

If you haven't used these in Inventor before it may be worth going through the Sketch Constraints tutorial.

 

Hope this helps and feel free to get in touch for anything else,

Indy



Inderjeet Wilkhu
SQA Engineer
Autodesk ShapeManager
Design, Lifecycle and Simulation
Autodesk, Inc.

Active Member
cmanzo1
Posts: 8
Registered: ‎07-24-2013
Message 8 of 9 (145 Views)

Re: re: shelling an object on the outside

12-20-2013 07:56 AM in reply to: wilkhui

Hello Indy,

 

Oh... I have been using constraints... just did not know that was their name. So, Inventor likes known, constrained forms....got it. The more definition, the easier it is to make solids out of them.  Like the sweep, extrude, combo!  So, you are creating 'the edge' condidtion and then merging it into the block. Shell after this is done. That is nice. I was doing alot of extrude, extrude, extrude with the occasional sweep when it worked. But this has been getting me clunky corners, so I will try this other work flow as you have outlined. 

 

I was also able to, finally, make the sweep sketch 1.8mm larger, sweep it, and then shell it down inside.  Not sure why it was a problem to make it larger, but there you go. I also cleaned up the sketch, so that might have helped a bit.

 

Thanks for your help here - have a great holiday!

 

Christopher

Employee
wilkhui
Posts: 98
Registered: ‎06-28-2012
Message 9 of 9 (138 Views)

Re: re: shelling an object on the outside

12-20-2013 08:12 AM in reply to: cmanzo1

Hi Christopher,

 

That's correct, in general more definition makes life easier later on. Like everything else, it gets faster the more you practice and if you get stuck then the online Inventor community is always ready to help.

 

Hope you enjoy your holidays as well :smileyhappy:

 

Indy



Inderjeet Wilkhu
SQA Engineer
Autodesk ShapeManager
Design, Lifecycle and Simulation
Autodesk, Inc.

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