What is the 4 axis CNC router?

In a broad sense, a 4 Axis CNC Router machine refers to a CNC machine whose processing path include X, Y, Z, and A axis. And we are going to talk about a 4 axis machine whose spindle can swing left and right. Because the spindle of this type of CNC can swing left and right, the spindle can approach the work piece from multiple different angles and efficiently process three effective processing surfaces. This CNC machine can realize not only the plane engraving, but also the 3d carving of irregular work pieces. And this type of wood CNC machine is suitable for common work piece, three-dimensional work piece, complex work piece and irregular graphics processing.