5 Replies Latest reply on Jan 10, 2014 3:24 PM by Jerry Steiger

Having trouble designing a spring. What am I doing wrong?

Valentina Tina Jan 5, 2014 5:30 PM

Hello.

I'm fairly new to CAD, but I know most of the basics.

I am trying to design a spring with 2 inefficient revolutions (1 on each side) and 9,5 efficient revolutions - 11,5 total. Firstly I sketched a circle with a dimension of the middle diameter of the spring. Then I created a helix with a variable pitch/rotations (the height of the spring matches the desired height), and a circle piercing the helix. When I try to create a sweep boss/base I get an error saying 'the sweep operation failed to complete'. I'm guessing the thickness of the circle is too big to complete the sweep.

I am attaching a file of my helix sketch.

Could someone please help me design the spring?

Thank you in advance!

Spring.SLDPRT.zip 55.4 KB

Re: Having trouble designing a spring. What am I doing wrong?

Surendra Narayan Jan 5, 2014 6:46 PM (in response to Valentina Tina)

Hi Valentina,
You are correct...the 6 mm diameter spring causes a failure due to the parameters you have at the bottom of the path.
(Pitch = 6mm. , Rev = 0, Height = 0 and Dia = 50 mm.) I have attached two images:
Figure 1

Figure 2

You can depending on your design intent:
1) Keep the path as is and reduce the diameter of the wire, In Figure 1, I reduced the diameter from 6 mm to 3 mm.
2) Keep the diameter the same and increase the pitch for Rev 0. In Figure 2, I increased the pitch from 6 mm to 9 mm.
Regards
Surendra
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- Re: Having trouble designing a spring. What am I doing wrong?
  
  Valentina Tina Jan 6, 2014 7:39 AM (in response to Surendra Narayan)
  
  Thank you for your reply Surendra.
  
  The thing is, the spring is supposed to be 6mm thick. I'm going to try to design it by increasing the first and second pitch.
  Could I kindly ask you for the .sldprt of the second spring anyway? In case I won't succeed on my own.
  
  Thank you again for the tips
  
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  - Re: Having trouble designing a spring. What am I doing wrong?
    
    Joseph Sensenig Jan 6, 2014 8:12 AM (in response to Valentina Tina)
    
    Hi Valentina.
    
    I tried to design a spring as well shortly after I started using SW. I decided it is fairly tricky. I found a macro from 3D Content Central that SW will run, and will design about any spring you want. The only thing is the taper does not seem to work.
    
    Just save the macro to your computer, then in SW, go to <Tools<Macro<Run< and select the macro.
    
    Hope this helps.
    
    Spring Macro.swp.zip 169.0 KB
    
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  - Re: Having trouble designing a spring. What am I doing wrong?
    
    Surendra Narayan Jan 6, 2014 7:40 PM (in response to Valentina Tina)
    
    Hi Valentina,
    Here you go.
    Regards
    Surendra
    
    Spring.SLDPRT.zip 749.3 KB
    
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  - Re: Having trouble designing a spring. What am I doing wrong?
    
    Jerry Steiger Jan 10, 2014 3:24 PM (in response to Valentina Tina)
    
    Valentina,
    
    The problem is that SolidWorks can't handle non-manifold bodies, which is what you get when two of the coils just touch at the tangency point. One workaround is to very slightly change the pitch on the closed coils so that they aren't quite closed. With a 6 mm wire diameter you might try a pitch of 6.01 mm.
    
    Jerry S.
    
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