NUMERICAL CONTROL APPARATUS WITH AUTOMATIC TOOL DETERMINATION FUNCTION

Abstract: The apparatus is provided with a tool file storing the tool number of a tool and the tool number of a tool which is used in the step before the step in which the first tool is used. In response to a final machining tool command (S3) for each machining step which is input from an input device, tools to be used and the tool order are determined according to the tool file (S5, S6, S7) , and a numerical control machining program is prepared and stored (S8, S9) according to machining configuration data input from the input device, and the thus-determined tools and tool order.

Description: SPECIFICATION NUMERICAL CONTROL APPARATUS HAVING AUTOMATIC TOOL SELECTION FUNCTION Technical Field The present invention relates to a numerical control apparatus having an automatic tool selection function. Background Art In a conventional numerical control apparatus, when a series of machining operations are performed at a single position with different tools, the tools are designated in an order of machining operations, and the machining positions must also be designated in units of tools. However, in the respective machining positions, a workpiece must be often machined in a predetermined order of machining steps. Even in this case, according to the conventional numerical control apparatus, each tool and its machining position must be designated. For example, when tapping is performed, the tools are a center drill, a prepared hole drill, a chamfering drill and a tap, and the order of machining steps is a predetermined or standard order. When a nominal diameter of the tap is designated, nominal diameters of other center and prepared hole drills are determined. However, according to a conventional numerical control apparatus, a tool and a machining position must be designated even for the standard tools and the corresponding order of machining steps, resulting in inconvenience. Disclosure of Invention It is a first object of the present invention to improve the drawbacks of the conventional numerical control apparatus having an automatic tool selection function wherein tools and an order of machining steps need not be specified for tools used in a single machining position and a predetermined order of machining, and a tool and its machining position in a final step are designated to automatically determine the previous tools and the order of previous machining steps. It is a second object of the present invention to provide a numerical control apparatus having an automatic tool selection function wherein a name of a tool used in a final step of each machining cycle, its nominal diameter and its machining position are used to automatically determine the tools and the order of machining steps when a plurality of tools are used at a single machining position. In order to achieve the above objects of the present invention, there is provided a numerical control apparatus having an automatic tool selection function, characterized by comprising: an input unit for entering numerical control machining data such as machining shape data and tools to be used; a standard tool file for storing at least tool numbers of tools used in machining and tool numbers of tools used in previous steps to each machining step in standard machining; means for searching a final tool of each machining step entered at said input unit, the final tool being searched from said standard tool file, and for sequentially detecting tool numbers of previous steps so as to determine tools and an order of machining steps for the respective machining steps; machining program producing means for producing a numerical control machining program of the machining steps in accordance with machining shape data which is given for each machining step entered at said input unit, and tool data determined by said tool sequence determining means; and means for storing the numerical control program. In order to perform machining different from standard machining, a -special tool file for storing different tools and the order of machining steps is provided. The tool and tool order determining means accesses the special tool file and the tool file in the order named. In this manner, even when special machining is performed, the tools and the order of machining steps can be automatically selected. Tool name data and nominal diameter data thereof may also be stored in the tool file and the special tool file. In this case, tool designation can includes'the tool name and the nominal diameter thereof. The numerical control apparatus according to the present invention has the arrangement described above. When only the machining position data and the final machining tool data are entered, the necessary tools and the order of machining steps are automatically selected. Therefore, the machining position need not be entered in units of tools. The numerical control program can be easily produced at a high speed. Even an unskilled worker who is not accustomed to numerical control machining can perform NC machining by designating the final machining tool of each machining cycle. As a result, machining errors can be greatly decreased. Brief Description of Drawings Fig. 1 is a block diagram of a numerical control apparatus according to an embodiment of the present invention; Fig. 2 shows part of a tool file used in the apparatus shown in Fig. 1; Figs. 3A and 3B are respectively tables for explaining the formation of a special tool file; and Fig. 4 is a flow chart for explaining the operation of the apparatus shown in Fig. 1. Best Mode of Carrying Out the Invention The present invention will be described in detail with reference to the accompanying drawings. Fig. I is-a-block diagram of a numerical- contro-l apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a central processing unit (to be referred to as a CPU hereinafter); and 2, a ROM for storing a control program for controlling the overall operation of the apparatus. The control program stored in the ROM and the CPU 1 constitutes a tool and tool order determining means and a machining program producing means. Reference numeral 3 denotes an input unit such as a keyboard for entering machining data such as a machining shape and tool designation. Reference numeral 4 denotes a RAM for storing processed data; 5, a CRT of a display unit for displaying a produced program or the like; and 6, a memory means for storing a tool file and a special tool file which will be described later, and a produced numerical control machining program. In this embodiment, the memory means 6 comprises a nonvolatile memory such as a bubble memory or the like. Reference numeral 7 denotes a bus. Fig. 2 shows part of the tool file. The tool file includes items such as tool number data, tool name data, nominal diameter data, tool length data and tool data representing a tool used in the immediately previous step. These data for all tools used in the corresponding numerical control machine tool are stored in the tool file. Referring to Fig 2, assume that tool number 1001 is designated in tap machining. The previous tool number is given to 1002 after reference to the tool file. The previous tool number of tool number 1002 is given by the tool file to 1003. In this manner, when the tool file is used and the final tool number is specified in each machining cycle, the first to final standard tools in this cycle can be automatically designated. The tools designated by the tool file and their order are standard ones. In the corresponding machining, when the standard tools and the -correspondin^ord-er of--machining steps are-not used, a special tool file is produced to designate special tools and a corresponding order of machining steps. In the tool file in Fig. 2, when tapping is performed by designating tool number 1001, the previous tool numbers and order are designated as 1002, 1003 and 1006. Assume that a drill with tool number 1005 is used in place of a drill with tool number 1003. In this case, when tool number 1001 is entered at the input unit 3, the CpU 1 searches the tool file and causes the screen of the CRT 5 to display the standard tapping tools and a corresponding order of machining steps, as shown in Fig. 3A. Then, tool number 1005 is entered in place of tool number 1003 in a list of the special tools and a corresponding order of machining steps. These data are stored in a special tool file shown in Fig. 3B. As a result, the tools and the order of machining steps which are designated by the tapping tool with tool number 1001 are given in an order of 1006, 1003, 1002 and 1001 in the standard tool file. However, the tools are designated in an order of 1006, 1005, 1002 and 1001 in the special tool file. When the standard tools and the corresponding order of machining steps are used, the special tool file need not be produced. In other words, only the standard tool file is required. The numerical control machining program is produced by using the standard tool file and the special tool file. Data is entered at the input unit 3 to set the apparatus in an edit mode. The CpU 1 causes the CRT 5 to display a program so as to edit the control data. Machining shape data and machining tool command are entered at the input unit 3. As shown in the flow chart of Fig. 4, the cu 1 discriminates in step S1 whether or not the machining shape data is entered. If YES in step SI, the entered machining shape data is displayed on the CRT in step S2. However, when the machining tool command is entered, i.e., when the tool number of the final tool used in each machining cycle is entered, the CPU 1 searches for a special tool file in the nonvolatile memory in step S4. If the input tool number is not found, the CPU 1 searches the standard tool file in step S5. When the designated machining tool data is found, it is diplayed and stored in step S6. When the tool number of the previous step is stored in the special tool file or the standard tool file in step S7, the CPU 1 searches the special or standard tool file again to find the tool number of the previous step in steps 54 and S5. When a tool which has nowt been assigned with the tool number of the previous step is found, the CPU 1 discriminates in step S7 that this tool is the first tool in the machining cycle. When an entry switch of - the input unit 3 is depressed, the CPU 1 as the machining program producing means causes the nonvolatile memory 6 to store the machining shape data and the machining tool data (tools and the order of machining steps) read out from the special and standard - tool files, thereby producing and storing a one-cycle machining program (steps S8 and S9). In this manner, when the special tool number finally used in each machining cycle is entered, the numerical control machining program of the entire NC control operation can be stored in the nonvolatile memory such as the bubble memory 6. When the special and standard tool files are searched for machining tool data (tool number), and this data is not present therein, the CPU 1 causes the display 5 to give an indication that the desired tool data is not found in step S5'. When a data cancel is not performed in step S10, the operation from step S1 is automatically restarted. In the above embodiment, and the special tool file is used. However, the standard tools and the corresponding order of machining steps which are stored in the standard tool file can be used for the respective machining steps, and the special tool file need not be used. In this case, the operation in step S4 in Fig. 4 is not required. In the above embodiment, the tool designation is performed by the tool number. However, when there is only a single combination of each tool and the nominal diameter, the tool name and its nominal diameter may be used in place of the tool number.

Claims: CLAIMS 1. A numerical control apparatus having an automatic tool selection function, characterized by comprising: an input unit for entering numerical control machining data; a standard tool file for storing at least tool numbers of tools used in machining and tool numbers of tools used in previous steps to each machining step in standard machining; means for searching a final tool of each machining step entered at said input unit, the final tool being searched from said standard tool file, and for sequentially detecting tool numbers of previous steps so as to determine tools and an order of machining steps for the respective machining steps; machining program producing means for producing a numerical control machining program of machining steps in accordance with machining shape data which is given for each machining process entered at said input unit, and tool data determined by said tool sequence determining means; and means for storing the numerical control program. 2. An apparatus according to claim 1, characterized by further comprising a special tool file for designating a tool different from that designated by said standard tool file, said tool and tool order designating means being searched from said special tool file and said standard tool file in an order named so as to determine designated tools and a corresponding order of machining steps. 3. An apparatus according to claim 1, characterized in that said standard tool file further stores tool name data and nominal diameter data thereof, the tool designation being performed by the tool name data and the nominal diameter data. 4. An apparatus according to claim 2, characterized in that said standard tool file and said special tool file further store tool name data and nominal diameter data thereof, the tool designation being performed by the tool name data and the nominal diameter data.

Inventors: INOUE, TSUYOSHI, NAGAMINE, TSUYOSHI, TORIYAMA, SHUJI
Applicants: FANUC LTD
Application year: 1984
Main classification: B23Q15
IPC codes: B23Q3, B23Q15, G05B19