living hinge
 

I'm designing a small plastic part with a living hinge . I have the specifications for the hinge itself , but I'm not sure how to model its operation in 3d cad - where is the axis of rotation , or is there more than one? It's a catch that fits over a peg so I need to be able to visualise the sweep it makes and it's final position. Any ideas?

Re: living hinge
 

I don't know of any way to simulate this accurately in CoCreate Modeling. You cannot deform a single solid part like that. The FEA module can only simulate small linear deformations, not the large deformations that are required for flexing a plastic hinge. You might be able to fake it using sheet metal bending operations but I don't know if it would be accurate. If you just want visualization you could cut the part at the hinge then use Assembly relations to rotate the hinge portion and animate it, but you would have to know how the hinge moves.

For people like me who didn't know what a living hinge is, a quick web search turned up this page.

http://www.efunda.com/designstandards/plastic_design/hinge.cfm

Re: living hinge
 

hello,a lot of vendor provide 3d model in many kinds of format to its standard parts product, you can ask your vendor about this information.

Re: living hinge
 

sorry miss your question, but some vendor still provide 3d model for it's real working suitation, for example the extension/compress spring, or you need to create animation yourself according your spec.

Re: living hinge
 

There are a few good plastic Design Guides out there that would greatly assist you in making a living hinge; Honeywell (Allied-Signal) Plastics Guide, GE Plastics (now owned by SABIC) has a good guide, the Brigham-Young University Plastic Guide, Ohio State Snap-Fit Guide 619, Bayer Plastics ATI Design Guide, Borg-Waner Plastic Design Manual, The ASME Snap-Fit Guide, DuPont Plastic Molding Guide, The NJIT of Plastic to Plastic Fastening, Celanese-Ticona Plastic Snap-Fits for Assembly, VCC-Cliplite LED Snaps, Ryton Design Guide, Basell PP Guide, and the Lifetime Hinges on Good Design; Injection Molding Magazine -December 1996.

Most of these can be found easily on the web. In a google search, use the " -filetype:PDF " option for " plastic snap design "

With a CAD model living hinge, you will need to bisect the flexing axis to model the before and after joint. If it flexes you will need to use angles to project the deformation onto some planes. Personally with something like this, I've done it easily in another CAD software and verified the results using ANSYS, but it might be doable in CoCreate with more operations.