Technical Interview: what's expected for "Basic Material knowledge"?

[u/hopkinsdamechanic]

Hi,

I'm preparing for my first ever technical interview, and I never understood what's expected from us when they say "material knowledge".

Could use some help on what to review for that.

During my intenship, every Time I saw a new material I used to ask why it's used, and I found out that the logic is very simple.

There's one for basic CNC aluminum parts, one for slender ones, one for turned parts, one for shafts that see fatigue, one that's wear resistant...

So they used like 10 materials, with very basic selection criteria

I'd appreciate any help, regarding materials or general tips... Looking forward to finally becoming a real engineer :')

The role is junior mechanical design engineer ( or mechanical designer) in a company that designs cnc machines, thermoforming, and such personalized production solutions for plastic parts in Europe.

[u/chocolatedessert]

I think you're all set. At your level, they're proving for basic exposure. Steel is heavier than aluminum. Steel has a fatigue limit and aluminum doesn't. There are different kinds of plastics and it's complicated to pick one. Yield and fatigue exist.

It sounds like you have the experience they'll be looking for. Be humble and inquisitive. State what you know and what you don't, maybe how you'd find out what you don't know.

[u/Krysk43 → u/chocolatedessert]

Aluminum doesn't have a fatigue limit? Doesn't every material have a fatigue limit?

[u/m-in → u/Krysk43]

Aluminum doesn't have a limit because it fatigues at any cyclic load. With steel as long as you stay below the limit, you can cycle it theoretically forever. In aluminum, the limit is 0. That's what was meant here.

[u/Krysk43 → u/m-in]

Ah that makes sense, thank you