CAD Forum

Hi,

I am currently modeling a few different snap features to retain a cover to a plate and circuit card between the 2 and having trouble visualizing what the snap looks like or how I would model it in the collapsed condition:


you can see it doesn't look right maybe I need to use splines?

If anyone has a good resource or something that explains snaps better that what is on the web as already downloaded a ton of pdf's that give a bunch of long formulas but none seem to define the relationships for a given material.

Thanks in advance,
Jim

The material is going to bend, not compress like you're showing it.

If you want to do all the calcs I'd look at beam load and deflection calculations. it's not going to be easy to do that long hand. You might be able to do a beam calc and sweep it though for an approximation.

What I'm wondering is if you could do a simulation and find the deflection and then save the resultant model. I've never done that but I could have sworn I read somewhere you can save the results of simulations.

Personally, I would continue the slots into the disc at the base of the feature just to allow more flexure.

The 4 prongs will come together in the center. I would just use a 2D sketch block to show it deflected. Take 4 of those 90 degree slices and move them all toward the center until they touch. Then the hole the prong snaps into needs to be slightly bigger than that.

Hi again,

This is what I was thinking the one sketch is the at rest position:
This is really my first time doing snap features on plastic and just trying to get my head around what is going on so to speak

Regards,
Jim

There are calculators you can use to make sure your design is adequate. I will use simulation express (because that's what we have) to check that what I have is reasonable. I'd model it undeflected and then use a sketch or copied surfaces for the deflected version.

Hi,

Tried the simulationxpress for the first time evidently I don't have the inputs correct:
Regards,
Jim

JMOS4 wrote: ↑Thu Apr 08, 2021 9:10 am Hi,

Tried the simulationxpress for the first time evidently I don't have the inputs correct:

image.png

Regards,
Jim

Having never tried this, my first thought is that you would want to deflect at least the two opposite tangs at the same time and have them set for "No Penetration" so they would stop upon contact.