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What are the best practices for designing snap-fit features to ensure ease of assembly?

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H
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Hey everyone, I’m creating a molded ABS enclosure for an electronic product with snap-fits to close the enclosure. I’m not sure of the best direction – I’ve looked at some products, I see little consistency. I’d love to hear from someone who’s tackled this before?

Solved by Daniel

Hey Henry! Cantilever snaps are the most common type because they're simple and effective. They work by having upstanding features from one case half that enter and hook into the other. When pressed closed, these features flex and then snap back to latch securely.

    • D

      Hey Henry! Cantilever snaps are the most common type because they’re simple and effective. They work by having upstanding features from one case half that enter and hook into the other. When pressed closed, these features flex and then snap back to latch securely.

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        Daniel

        thanks, Daniel. That all makes a lot of sense. What about the slot where the hook snaps into? Can you offer some thoughts about designing that part?

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        Henry Moore

        The geometry of the slot is easier in some ways. It needs to be wider and deeper than the hook. Also, include a small lead-in or radius at the entry.

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        Daniel

        Great. I want the enclosure to stay closed, but I also need to be able to open it for maintenance. How do I balance these?

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        Henry Moore

         You’ll need to find a sweet-spot where the snap is secure but not too difficult to open. Start with CAD simulation if you can. Start with a hook feature that’s a bit too big in an early prototype, and file the hook until it is a bit weak. Remember, make the hooks a little too SMALL in the tooling – increasing them is metal off and cheap.

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      • H
        Daniel

        Daniel, this is where your advice took me, in cutaway detail I like it, what do you think?

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        Henry Moore

        Great work – one detail though, you could give the snap a little room to move where its tip looks like it hits the lowercase.

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What are the best practices for designing snap-fit features to ensure ease of assembly?
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