What lean pipe joints are needed to build aluminum alloy material shelves?

Building aluminum alloy material shelves mainly relies on wire rod connectors (joints) to lock and fix the pipes, commonly requiring the following types:

Right angle joint: Connecting two vertically intersecting wire rods, it is the basic component for connecting shelf columns and beams, and is the most widely used.
-T-shaped connector: used for intersecting three wire rods to form a "T" - shaped structure, commonly used for supporting connections between crossbeams and the middle section of columns.
-Double tube joint: Two wire rods are fixed side by side in parallel, commonly used to strengthen the strength of laminates or columns.
-External hug/internal direct head: used for extending the docking of two wire rods on the same straight line, or achieving external locking in different directions.
-45 °/slant support joint: slant support is added on the diagonal of the side of the shelf to improve the torsional resistance and stability of the whole frame.
-Foot cup/caster: a support component at the bottom of the shelf, with fixed foot cup selection and mobile brake caster selection.