I want to bend steel/aluminium plates exactly 90 degree so that it will be similar to a c channel. Are there any good techniques/tools to do so perfectly?
Sure thing! The C-channels were done by roll forming (Roll Forming - YouTube), so we can rule out that process for the small shop, as it requires tooling to be made.
The tool you need is called a “brake”, and comes in a couple styles. Small shops (and probably the best thing for what you’re looking for) use a box-and-pan brake: Sheet metal on the box and pan brake 101 - YouTube You can find these in all sizes, even a super-economy at Harbor Freight: https://www.harborfreight.com/18-inch-bending-brake-39103.html
The other style of brake is the “press brake” (Sheet Metal Forming using Press Brakes - YouTube) and there’s even a small version of this, handy for a U-team, and it includes a shear and rollers: https://www.harborfreight.com/30-inch-shear-press-brake-and-slip-roll-5907.html
Can confirm. Our class uses a sheet metal brake to bend or break/shear the plate steel or aluminum. Burl-less cuts, no heat, and its ultra-safe compared to everything else.