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I would like to print a custom version of something akin to this rugged case that was originally created using injection molding:

ea weather proofed tablet with over-molded rubber

The outside consists of a material that is a bit softer than the main body.

It is used to protect the electronics against drops when the case falls onto the floor.

Unfortunately, I don't know which material this is, and I don't know which method I could use to measure its softness.

I would therefore like to ask if anybody has experience with such a softer outer hull and can tell me which material could be used when I want to 3D print it.

I would like to use this case in a hospital environment.

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TPU or TPE

You are looking for a Thermoplastic Urethane or Theroplastic Elasomere. Both are types of FDM printable synthetic rubbers, which can be used to create such flexible buffers. However you need to properly design your casing with the correct thickness and hardness of the material in mind - you can not just take the dimensions and design from an over-molded material.

Most flexible filaments need to be printed hollow to achieve good protection for the part. In some cases, you might want to use a foaming TPU/TPE that expands and creates cushioning voids, allowing to slow the part falling down to a slow enough speed to protect sensitive circuits.

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  • $\begingroup$ Thank you. Can you please tell me which possible pitfalls you might see? $\endgroup$
    – tmighty
    Sep 8, 2022 at 21:23
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    $\begingroup$ @tmighty, the obvious pitfall is printing it solid. TPU isn't like foam rubber -- it doesn't compress much. A good fall protector is as much about picking the correct infill as it is about the overall shape. $\endgroup$
    – Mark
    Sep 8, 2022 at 23:34
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    $\begingroup$ Also, not every printer can handle these materials well, and you may need print much slower (as low as 25mm/s) than you are accustom. $\endgroup$ Sep 9, 2022 at 14:20
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I do it a couple of ways.

I use TPU which is pretty good for impacts and either make it thick or stiffen it with another filament as an inside or outside shell.

But TPU is what you want for this project because it's flexible in the way you need it to be.

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  • $\begingroup$ Thank you. Can you also tell me what you would use for the stiff interior plastic? $\endgroup$
    – tmighty
    Sep 8, 2022 at 13:37
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    $\begingroup$ I have used both PLA and PETG for that. Just a plate of it rather than a full cover. But TPU on it's own is fine as well. I used the plates because I wanted something totally rigid to build a swingout stand with $\endgroup$
    – Kilisi
    Sep 8, 2022 at 18:53
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Case designers usually use TPU for flexibility and polycarbonate for stiffness

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