In terms of cross-section, there are many kinds of cross-sectional shapes of shelf columns, but from the current market share, basically mainstream profiles are still basic “Ω” type, some of which are relatively simple in structure, mainly used for lightweight shelves; The multilateral rolling structure is relatively complicated, and the processing technology is also relatively complicated, mainly used for medium and heavy shelves. The other shapes derived from the basic type are mainly to increase the bending on the longer side to enhance the rigidity and stability of the shelf column.