The 2-axis, 3-axis, 4-axis and 5-axis, which refers to the number of axes of movement.
The 2-axis is generally designed to left-and-right movement, forth-and-back movement, such as 2-axis broom tufting machine; rotation and forth-and-back movement, such as roller brush making machine.
The 3-axis is designed to left-and-right movement, forth-and-back movement and rotation (or change to up-and-down according to the shape of the brush).
The 4-axis can be left-and-right movement, forth-and-back movement, rotation, forth-and-back swinging.
The 5-axis is mainly designed to left-and-right movement, forth-and-back movement, up-and-down movement, rotation and swinging. It's suitable for many kinds of brushes.