Corner Bracket angle support AJ28

This is a standard mechanical part to connect two aluminum beam in right angle.
We can see a lot of these parts (those are made of aluminum ) in many DIY CNC machines or 3D printers.
The size is length 28mm , height 28mm , and depth is 20mm. Holes are for two M5 screws (D 4.5mm )
I made the wall and base thicker to improve strength.

It's for 2cm width aluminum beams.