The invention relates to a machining device for the machine-assisted production and machining of dental workpieces (16), particularly of artificial teeth and/or other dental replacement parts, the at least one workpiece (16) being clamped in at least one workpiece retainer (11) which can be raised, lowered and rotatably driven, is positioned on a rotational axis (9), and, for the purpose of machining, feeds said workpiece (16) to at least one tool spindle (4, 5, 6) that is rotationally driven and has a tool (7) secured thereto, an additional tool retainer (2, 2a, 2b) with a plurality of tools (7) arranged thereupon being associated with said workpiece retainer (11, 11a, 11b) and lying opposite on one side thereof, and a workpiece changer (22, 22a, 22b) which receives the workpieces (16, 16a, 16b, 16c) to be machined, such that they can be exchanged, being arranged on the other side of said workpiece retainer (11, 11a, 11b).

An automatic tool changer (ATC) serves as an ATC for automatically changing a tool attached to a lower tool rest of a machine tool. The ATC includes a robot arm and a movement mechanism unit moving the robot arm between inside and outside of a machining area. The robot arm has a base unit coupled to the movement mechanism unit, an arm unit pivotably coupled to the base unit, and a gripping unit provided in the arm unit and detachably gripping the tool. The arm unit is formed to extend in an arm shape from the base unit toward the gripping unit, and swings on a pivot axis as a fulcrum relative to the base unit. By such a configuration, an ATC implementing an automatic change of a tool by a simple and compact mechanism and a machine tool including such an ATC are provided.

In order to be suitable for space-saving of a multi-functional processing machine in which a tool main spindle device is disposed at a center of an opposed biaxial lathe, there is provided an automatic tool exchanger provided in the multi-functional processing machine, the automatic tool exchanger including: a tool magazine that is disposed in a machine body front surface upper portion of the multi-functional processing machine and is configured to house multiple tools for exchange with respect to the tool main spindle device; a shift device configured to move the tool between the tool magazine and a tool exchanging position with respect to the tool main spindle device; and a tool changer configured to exchange the tool between the shift device and the tool main spindle device.