The device and the corresponding method according to the invention relate in particular to a CNC machine tool and a machining method preferably for large machining patterns. The CNC machine tool may comprise a machining head 2 which may be connected to a Z-axis 1 such that it can be manually and/or automatically changed, and which may have at least two tool spindles 3 for receiving tools 4. The Z-axis 1 can be moved in a linear manner at least along two linear axial directions. The Z-axis 1 and/or the machining head 2 may have at least one axis of rotation.

A CNC dual-spindle transmission device is installable on a CNC dual-spindle machining center to receive first and second spindles of the CNC dual-spindle machining center to mount thereto. The CNC dual-spindle machining center includes a base, a machining table movably mounted on the base, and a vertical column erected upright at a rear portion of the base. The CNC dual-spindle transmission device includes a linear rail assembly mounted to the vertical column, a first slide seat slidably mounted to the linear rail assembly and receiving the first spindle to mount thereto, a second slide seat extending across the first slide seat and slidably mounted to the linear rail assembly in a manner of being spaced from the first slide seat to receive the second spindle to mount thereto, and first and second power units mounted to the vertical column to respectively driven the first and second slide seats to move.