Compression spring model

[WDickman]

I need help. I want to design a compression spring - ends closed & ground - and I can't seem to find any info on just how to do the different pitches on the ends for the "closed" form. Someone must have come across this before. Any help will be appreciated. Are there any spring design macros out there?

 

[CorBlimeyLimey]

Which version of SW are you using?
SW07 has a variable pitch helix function.

If you don't have SW07, you will have to create a composite curve from a begining, middle and end helix.

 

[jacek0841]

SW07 has a variable pitch helix function

I think SW2006 too ...

 

[WDickman]

Thanks for the replies. I am running 2006 & have 2007 but can't install until my main customer does, and they like to wait for a few SP's are under the bridge...
Lee Spring has a tie - in with SolidWorks to download their springs, but they are imported and thus can't be modified to go from free length to working length. Makes the files almost worthless except for the purchase drawing view. C'mon 2007!

 

[israelkk]

I do not understand why are you wasting time to show the closed and ground ends. No one will use the SW model to manufacture the spring.

 

[CorBlimeyLimey]

WDickman ... You can install multiple SW versions providing you install to separate folders. Even if you don't use SW07 for production, you will be able to test and become familiar with it.

jacek0841 ... You are correct. Variable pitch was introduced in SW06.

 

[AnnaWood]

Here is a link to a zip that contains a couple spring files. I use these for my designs. Enough detail to satisfy me and the BOM for the assemblies.

Click on the last feature (extrude) and change that dimension and you model will update. I have an equation to drive the spring. There are multple configurations for open, closed, free length, etc.

You can mate to the flats on the end, the axis in the Lee spring and the outside dia of the die spring. Use the configurations to drive the motion in your tool.

http://visualvault.auerprecision.com/ViewFile.aspx?DlID=6eac1926-039a-436a-8133-1b3ddbf242ee

Regards,

Anna Wood
SW06 SP5 x64, WinXP x64
Dell Precision 380, Pentium D940, 4 Gigs RAM, FX3450
WD Raptors, 1 Gb network connection

http://designsmarter.typepad.com/solidmuse

 

[meintsi]

In most cases, you probally dont need to model the closed coils. The simple cuts Anna's models include will work just fine. When creating section views, the springs very rarely appear to be floating in space and the added detail helps other departments to understand some of the more complex assemblies we have when they are looking for information.

That being said, we model all spings "as designed". (I even go so far as the exact number of turns as generatd by our spring design program.)

Unfortunately, the variable pitch helix in SolidWorks does not work very well for this if you need multiple configurations (compression lengths).

For a simple compression spring, a layout sketch on the top plane includes the wire diameter, spring diameter, and free length.

The helix is created on the front plane (using height and revolution) by an equation driven composite curve of three parts. The first dead coils height is the wire diameter plus a small gap ( uusally +.001" to .003" dependening upon the wire diameter and compression of the configuration - the larger the wire or the more compressed the spring becomes - the greater this gap has to become to avoid rebuild errors.) Start with a single (whole)revolutions here until you get the feel for how the model reacts.

The height of the active coils is the free length minus the height of the first and last dead coils where the last dead coil mimics the first.

Configurations are created by changing the OAL of the spring in the layout sketch.

More complex layout sketches can allow for tapered springs, springs where the last coil only is wound tighter, etc...

I not sure if I have any of the files left in a version earlier than 2007 but can post a model to the web here from work anyway.

Remember...
[navy]"If you don't use your head,[/navy]
[navy]your going to have to use your feet."[/navy]

 

[btcoutermash]

I currently use this macro from SW's web site. Works very well. Hope it helps...

http://www.solidworks.com/pages/services/CodeExamples.html

"How to create springs using a macro feature"