Question

[SHADFAN]

So I am wondering if the motherboard shouldn't be mounted on something that is electrical conductive then why cases are made of metal? 

[boggy77]

strength and price. it's easy to insulate the mobo from the case.

a plastic case would need to have much thicker walls too be stiff enough.

carbon fiber is expensive.

[Drama Lama]

There are standoffs and the cases are regularly painted ( don’t know if the second matters 

Edited June 19, 2020 by Drama Lama

[SHADFAN]

8 minutes ago, boggy77 said:

strength and price. it's easy to insulate the mobo from the case.

a plastic case would need to have much thicker walls too be stiff enough.

carbon fiber is expensive.

 

8 minutes ago, Drama Lama said:

There are standoffs and the cases are regularly painted ( don’t know if the second matters 

I still don't understand. Is there like space between the mobo and the case? What's the insulator exactly? 

[Hairless Monkey]

1 minute ago, SHADFAN said:

What's the insulator exactly? 

Air. There is space from the standoffs. The standoffs actually help ground the board, as well.

[Eschew]

Hey there. My guess is that metallic chassis are easily mass-produced, malleable, sturdy, and heat- and water-resistant. Below is what I remember and reason from high school D.T. classes, please take it with a grain of salt, I'm not a materials specialist.

• Cheap wood (plywood, particleboard, MDF) isn't all that suitable for small, mass-produced goods with uniquely-shaped grooves, cut-outs, notches, and other what-have-yous (small relative to, say, your desk). On top of that, cutting out those tiny nooks and crannies would leave a lot of wasted wood. Wood also easily warps and/or cracks with humidity, temperature changes(?), and is flammable. And plywood and particleboard tend to leave a lot of wood dust floating around, if their edges aren't sealed with varnish.
• Plastic, while easily mass-produced, electrically non-conductive, and usually water-resistant, tends to warp with temperature changes, and is more fragile compared to metal.

[VIVO-US]

The motherboard stand-offs put enough of a gap between the board and case to prevent any of the electrical connection on the PC board from making contact with the metal case.  This makes short circuits impossible with a correctly installed motherboard.  The metal case doubles as a common electrical ground for the board and other components, making the build a little safer and more reliable.