This invention relates to a numerically-controlled machine tool (hereinafter referred to as "a machining center", when applicable) which has a tool magazine accommodating a plurality of tools which are automatically replaced by a tool exchanging arm, and can display the tool numbers assigned to the tools in the magazine.
In general, in the case where, in a machining center having a tool magazine accommodating tools, tools for which numbers assigned to the tool accommodating pots of the magazine are stored as tool numbers must be returned to the respective pots. Accordingly, in returning a tool, the tool magazine must be positioned during the standby period so that its own pot comes to the tool exchange position, and it is necessary to provide an auxiliary station for the machining center to grasp the next tool.
In the case where coded tool numbers are provided on the tools themselves, or tool numbers are stored in the memory device of a control unit in advance, the tools themselves have their own tool numbers, and therefore it is not always necessary to return the tools to the predetermined pots. However, a satisfactory display means for recognizing the tool numbers are not provided for the conventional machining center, and means for showing the change of all of the tool numbers due to tool displacement or exchange is not provided for the machining center.