Solid Edge – Spring Designer – Help!

[SillyOldDufferModerator @sillyoldduffer]

Anyone understand how SE’s Extension Spring Designer tool works?

It’s in the ‘Tools->Engineering Reference’ collection.  Looks straightforward.  In this example I’ve told it to calculate the load needed to extend a given spring:

Problem is when I press calculate, I get a red FAIL error and SE won’t create the spring.

 

The other design options fail too.  Either my spring requirements are breaking a hidden rule or maybe I don’t understand what I’m doing.

The spring I want is nothing special, a hooked extension spring 5mm diameter about 15mm long fully extended in 1mm wire.

The tool isn’t disabled: SE’s default settings for a large spring work:

Result: Green Pass!

 

Any suggestions?

Dave

 

 

 

[Grindstone CowboyParticipant @grindstonecowboy]

Tried to access this tool, but I must be doing something wrong, as it appears to be disabled for me. Odd, because I’m on the same version as you, according to what you posted in your Enigma thread the other day.

Stumped!

Rob

[SillyOldDufferModerator @sillyoldduffer]

Try it with an assembly loaded.  I now find it’s not available for me whilst working on a part.  Odd eh?

Dave

[David JuppParticipant @davidjupp51506]

Doesn’t the Help button do so?

[David Jupp]

On David Jupp Said:

Doesn’t the Help button do so?

Er, what Help Button?

With a part open for edit I looked Engineering Reference up with the command search and got this result:

 

Greyed out and tagged ‘This command is disabled in the current product state’.   Might be because the tool creates a new part, and dropping onto an existing one is daft.

Switch to an Assembly edit, and it comes alive:

 

If I could get the designer to generate a spring, I guess it could be added to the assembly.

Not worried about getting the tool to start, it’s that once designer is running, my spring parameters won’t make a valid spring.

Got a book about spring design, heavy going, and then the family dropped in for a visit.  Nice to them except the afternoon is gone!

Dave

 

 

[Grindstone CowboyParticipant @grindstonecowboy]

Managed to get to the tool, and can get a green PASS if the number of coils is specified (actually defaults to 10) and the hook type is one of the things you are looking for?? Not sure if this helps?

Options selected were:

EDIT – whilst creating this post, Dave posted again – maybe the Help referred to is the little question mark near the Pass/Fail result?

Rob

[David JuppParticipant @davidjupp51506]

I was thinking more of the button at bottom right of the dialogue, with Help written on it….

[David Jupp]

On David Jupp Said:

I was thinking more of the button at bottom right of the dialogue, with Help written on it….

Doh!  Hidden in plain sight.   Doesn’t help though, it just lists what’s on the tool anyway with no explanation of how the parameters interact.

Remembering my requirement is ‘The spring I want is nothing special, a hooked extension spring 5mm diameter about 15mm long fully extended in 1mm wire.’

Playing around this is the smallest PASS spring I could make, 55mm long, way too big:

The spring is part of the socket assembly, and it’s gigantic in comparison:

Looks like the SE Spring designer may not be able to generate small springs.  I guess the parameters have to be met within the Lo, Lp, and Lf dimensions, with a minimum wire diameter of 1mm (too big for me really), and meet the other spring requirements.

Possibly I can scale a big one down.

Maybe the compression spring tool will get closer.  Whilst springs can be drawn manually the helix and curved hooks are time consuming.

Dave

 

[Grindstone CowboyParticipant @grindstonecowboy]

Dave – try changing the material. I’ve just swapped to phosphor bronze and you get a choice of much smaller diameters.

Rob

[SillyOldDufferModerator @sillyoldduffer]

Scaling works, x0.15, as does hooking the spring in place with SE’s steering wheel tool.

New, problem.  Now the result is on screen, it’s apparent the sockets are very cramped.  The whole model is about half scale, causing various problems.   Looks OK, except I might have to start again.   I suspect simply scaling all the parts by x2 will break most of the assembly constraints.   SE doesn’t appear to support scaling an assembly with sub-assemblies all in one go.

Dave

 

 

[Grindstone Cowboy]

On Grindstone Cowboy Said:

Dave – try changing the material. I’ve just swapped to phosphor bronze and you get a choice of much smaller diameters.

Rob

Excellent! I’ll try it.

Many thanks,

Dave

[ChrisLHParticipant @chrislh]

Your original spring is very short (2 mm) and you don’t appear to have specified a wire diameter.

[ChrisLH]

On ChrisLH Said:

Your original spring is very short (2 mm) and you don’t appear to have specified a wire diameter.

If only I was that stupid!  What you’re looking at is the result of a failed Solid Edge calculation, not my input.   Something went wrong when SE attempted to calculate what load will cause a given spring to deflect a known distance.  Very likely my input was faulty, but I don’t see how.

In the workshop springs are very simple.  I just select one that’s about right from a box, or wind piano wire round a former.  SE calculates the spring from design parameters like load, extension, material, diameter, safety factor etc.  Seems very complicated and I don’t understand it by several miles!

Got a work-around, but I shall have to go back to why the tool doesn’t work as expected.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Shoot me down by all means … but I suspect that SE is simply applying a ‘sanity-check’ to your spring design, and rejecting something which is outside the envelope.

There is a lot of expertise involved in spring design, but do remember that ultimately you are only looking at a re-shaped Torsion Bar.

MichaelG.

[ChrisLHParticipant @chrislh]

It was a bit dim of me not to realise that what you showed was a failed working.

May be relevant, maybe not. You are probably aware of this but in case not, tension springs are commonly wound with preload so that a certain load has to be exceeded before the spring will extend.

Otherwise in the old days we used to use nomograms. With a bit of practice you can quickly get a new design and you can come at it from any direction depending on the constraints imposed by the job. If you would care to quote your inputs for your job I can easily run them through my nomograms and check for sticking points.

[SillyOldDufferModerator @sillyoldduffer]

Michael could well be right!

All I need from SE at this stage is a representation of a small spring of the type found in tape cassette player mechanisms. ‘nothing special, a hooked extension spring 5mm diameter about 15mm long fully extended in 1mm wire.’ In my application, the shorting bar on my Enigma project’s sockets, the load and movement are small. All the springs have to do is pull the shorting bar into contact across the sockets and stop the bar falling off!  Not critical.

SE can design springs, but it calls for parameters I don’t understand.  I suspect it may not be able to design small springs – I can only get big springs out of it!

Here’s an example that works with SE default inputs:

First the start conditions:

Second, the materials, a long list:

Third, the input parameters.  These are SE defaults and work, note the spring is huge compared with what I want!

Pressing ‘Calculate’ produces a shower of numbers, and a PASS:

 

Pressing ‘Create’ generates the expected big spring:

My problem is, what inputs should I specify to get a small weak spring.  And then, cos I like to understand if I can grasp it, what do the inputs mean?  This attempt fails, and it doesn’t seem unreasonable to me.

Delighted to be told I’m doing something obviously daft!  Not had anything to do with springs since Hooke’s Law over 50 years ago, when I was thinking about girls…

Dave

[JasonBModerator @jasonb]

Why don’t you just model it as a helical extrusion and add the hooks at the end if all you need is a representation of the spring

[Michael GilliganParticipant @michaelgilligan61133]

This might possibly be of some assistance, Dave:

https://www.acxesspring.com/extension-spring-design-guide.html

MichaelG.

[ChrisLHParticipant @chrislh]

I don’t have SE so cannot check what follows for your calculator. Inserting the above values my ancient nomogram I find I cannot make a spring design because there is insufficient information.

However if I assume a wire diameter of 2 mm, the following spring emerges.

Do = 20 mm,   d = 2.0 mm,   active coils = 5,   torsional stress = 320 MPa (very comfortable),   active spring length under the 90 N load = 13 mm (this is just the coils, the length of the hooks need to be added to get overall length.

What do you get from SE for these inputs ?

[JasonB]

On JasonB Said:

Why don’t you just model it as a helical extrusion and add the hooks at the end if all you need is a representation of the spring

Could do but

• The SE Spring Designer is quick provided I can make it work.
• So far as it’s possible. I’m in the hobby to improve understanding.
• A helical extrusion with added hooks is rigid.  In contrast, SE generated springs are recognised as elastic in assemblies and motorised animations.  Not needed for my Enigma, but useful for other models.

My current workaround is to generate a big spring with SE and scale down it to fit.

Dave

[ChrisLH]

On ChrisLH Said:

I don’t have SE so cannot check what follows for your calculator. Inserting the above values my ancient nomogram I find I cannot make a spring design because there is insufficient information.

However if I assume a wire diameter of 2 mm, the following spring emerges.

Do = 20 mm,   d = 2.0 mm,   active coils = 5,   torsional stress = 320 MPa (very comfortable),   active spring length under the 90 N load = 13 mm (this is just the coils, the length of the hooks need to be added to get overall length.

What do you get from SE for these inputs ?

Thanks Chris, I’m deep into another problem at the moment.  Watch this space!

Cheers

Dave

[SillyOldDufferModerator @sillyoldduffer]

Reporting back after a couple of hours stretching my brain yesterday!

As far as I can tell the Solid Edge Spring Designer doesn’t accept the parameters Chris lists, so no joy.   Looks as if the software doesn’t support the design method allowed by Chris’s nomographs.   Instead, and depending on the option selected, SE offers a list of mandatory parameters. I can’t pick and choose from them.  For example, wire diameter is usually an output, not an input.

Here’s an example that takes wire diameter as an input:

Asks for:

The values suggested by Chris result in a FAIL calculation, possibly because they were massaged by me so they can be plugged into the calculator.  And I don’t understand what I’m doing…   Time to think again.

The CAD spring downloaded from a catalogue looks good, but it’s incomplete.  It’s not what SE calls an “Adjustable  Part”.  Thus although the spring is represented dimensionally, it doesn’t stretch or compress under load when the assembly is animated.  Using a rigid spring locks the assembly; and – when that matters – the spring needs to be elastic.

Found a good YouTube video on modelling springs as SE Adjustable Parts.  Quite a lot to it so I’ll have to come back to it.

Thanks for the suggestion, I’m inching forwards!

Cheers,

Dave

 

[ChrisLHParticipant @chrislh]

Dave,

Although I have designed quite a few springs in my time I must confess myself totally bamboozled by the SE approach. The precise meanings of “Design spring at given loads” and “Test spring at given loads” escape me and the wire diameter does not seem to merit a mention despite its obvious importance. I know that the SE crew are not daft but I’m afraid I’m too set in my ways to want to wrestle with their approach. Sorry !

[Alan Wood 4Participant @alanwood4]

If you are just plain lazy you can download a 3D model for most of the MacMaster Carr range of springs.

[SillyOldDufferModerator @sillyoldduffer]

Thanks for trying Chris.  I feel better now someone who knows about springs can’t tune into the SE tool either!

From what I see, I think the SE tool is inflexible. It designs springs starting with the load, preload and some dimensions.  And if the load cannot be met within the dimensions and other parameters, it won’t create a spring, and doesn’t highlight why not.   Might be because it calculates big springs, and my springs are all small.   I’m baffled!

Thanks,

Dave

 

 

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