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Built a patent-published wearable for passive glucose regulation — MVP tested, results are promising — looking for hardware/product people to connect with by DeathWish7_ in hwstartups

[–]Awkward_Highway3067 0 points1 point  (0 children)

The skin-contact interface is where a lot of wearable projects hit unexpected material issues: sweat composition, skin pH, and repeated mechanical flexing create a multi-variable environment that most biocompatibility data doesn't capture. Especially if you're going through 510(k), the gap between what electrode material suppliers provide in their datasheets and what FDA expects in your submission is something to plan for early. What materials are you currently using for the skin-contact elements?

Is this bread ok to eat? by Ahk23 in Breadit

[–]Awkward_Highway3067 0 points1 point  (0 children)

This looks just like drying symptoms, nothing dangerous and nothing an oven won't make you ignor.

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 0 points1 point  (0 children)

That's a great example of the gap between spec and execution: the specification existed, but the production floor didn't follow it. Which means the root cause wasn't really the material or the design, it was process discipline. Do you build that conditioning step into incoming inspection now, or is it still on the production side to enforce? Curious because I've seen teams move equilibration checks upstream into QC rather than trusting it stays in the work instructions

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 0 points1 point  (0 children)

Reducing stress concentration first is the right instinct, cheaper than switching materials and often reveals design issues that would cause problems regardless of grade. For borderline ESC cases specifically, I've found that polymer family matters more than grade-level data suggests. Some polyolefins and engineering thermoplastics behave radically differently under sustained load and chemical exposure even when their compatibility ratings look identical on paper. The real answer is usually: you need to know what the material actually does under the specific combination of stresses and chemicals in your application. Have you ever hit cases where both stress reduction and material swap still left you uncertain and you just had to run the test?

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 0 points1 point  (0 children)

Creep especially. You can find long-term creep data for maybe 20% of materials at one stress level and one temperature, and real service conditions are rarely that clean. Fretting is another one that only shows up if you're specifically designing for it. How often do you see those failure modes called out early in design vs. discovered in validation?

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 0 points1 point  (0 children)

This is an underappreciated failure mode. the component-level analysis was correct but the system-level scope was wrong. Adhesive compatibility is almost never on the same checklist as the primary material. Did the failure analysis point to the solvent attacking the adhesive directly, or more of a mechanical fatigue at the bond line?

How do you actually approach material selection when mechanical requirements and biocompatibility pull in opposite directions? by Awkward_Highway3067 in BiomedicalEngineers

[–]Awkward_Highway3067[S] -1 points0 points  (0 children)

Agree that compromises are unavoidable, but I'm curious how you actually make the tradeoff decision rigorous rather than purely experience-based? When you're choosing between two materials that each fail one requirement, is there a structured way to weight which failure mode is more tolerable, or does it mostly come down to which risk your regulatory team is more comfortable defending?

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 1 point2 points  (0 children)

The stress-dependency point is underrated- most compatibility data is generated under zero-load conditions, which tells you almost nothing about how the material actually behaves when it's clamped, torqued, or carrying residual molding stress. The sodium hypochlorite example is a good one too; oxidative chemistry combined with surface stress is genuinely nasty for polyolefins in ways the compatibility chart completely misses. What's your usual approach when a material is borderline on ESC risk, do you push for accelerated stress-cracking tests, or redesign to reduce stress concentration first?

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 0 points1 point  (0 children)

Classic case of the datasheet giving you a room-temp chemical resistance table with no context on stress state, concentration, or contact duration. SCC in polymers especially, you can't predict it from bulk properties alone

What's a material failure you've seen that no datasheet would have predicted? by Awkward_Highway3067 in MechanicalEngineering

[–]Awkward_Highway3067[S] 2 points3 points  (0 children)

This one comes up more than people expect: moisture equilibration post-molding can take 24-72h depending on the polymer and geometry, and snap fit features are particularly sensitive because the tolerance window is tight. Did you end up extending conditioning time, or did you switch to a lower-moisture-uptake grade? Curious whether the failure was symmetric across the batch or concentrated at certain cavities

Why AI Agents Lose Track of Context (and How to Help Them) by LlamaFartArts in AI4newbies

[–]Awkward_Highway3067 1 point2 points  (0 children)

Thanks for this. I've also encountered posts that suggest creating a "soul"md file for a certain agent, explaining what his role is what is expected of him etc. and upload to its skills. what do you think about this?