JPH07108502B2 - Numerically controlled machine tool with automatic measurement function - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerically controlled machine tool having a function of automatically exchanging tools and a function of automatically measuring the size of a machining location, which is an automatic tool abnormality detection.

[Prior art]

2. Description of the Related Art Conventionally, as a numerically controlled machine tool having an automatic tool changing function, there is a machine called a machining center. For the method of indexing the position of the tool magazine in such a machine,
There are various methods. For example, the tools to be used are arranged according to the machining order, and the sequential method is used for indexing one step at a time, the fixed address method is used for indexing by specifying the identification number assigned to the tool pot, and the tool identification number. A variable correspondence table with the tool pot identification number is created, and each time a tool is automatically stored in an empty tool pot, the correspondence table is automatically rewritten, and in the machining program, the tool attached to the spindle with the tool identification number is used. There is a soft random method of specifying. In the above method, it is necessary that proper tools are correctly arranged in eight rows according to the machining order. In the above method, the machining program specifies the tool to be used by the identification number of the tool pot, so that the predetermined tool needs to be correctly stored in the predetermined tool pot. With this method, it is not necessary to store a specific tool in a specific tool pot, but the initial setting of the correspondence table can be performed without error, and the tool that matches the tool number specified in the machining program can be stored in the tool magazine without error. Need to be stowed. In any of the above methods, in short, it is necessary to store the correct tool corresponding to the tool planned to be used by the machining program in the tool magazine according to each promise. Since the tool size changes due to wear and the like, the tool correction amount is set in the machining program. However, if the correction amount is set incorrectly, the planned proper processing cannot be performed.

[Problems to be Solved by the Invention]

Therefore, when the tool stored in the tool magazine is replaced or the above-mentioned tool correction amount is changed, it is necessary to confirm whether the operation is performed without error. Conventionally, such confirmation has been performed by manual measurement and visual inspection by an operator. That is, immediately after the tool is replaced or the tool correction amount is changed, the operator manually measures the position, processing dimension, etc. of the processing location of the workpiece processed by the tool, and the scheduled processing is performed. It was confirmed whether the above operation was performed correctly by determining whether the operation was performed. Therefore, when a large number of tools are replaced, the work efficiency is low and the processing speed is lowered. The present invention has been made to improve the above-mentioned drawbacks, and an object of the present invention is to improve workability and efficiently perform processing.

[Means for solving problems]

The configuration of the invention adopted to improve the above problems is as follows. That is, the present invention, by program control, selects an instructed tool from the tool magazine in which the tool is stored and mounts it on the spindle, and an automatic tool change function, and mounts a measuring tool on the spindle to machine a workpiece. In a numerically controlled machine tool that has an automatic dimension measurement function to measure dimensions, the tools are divided into multiple groups according to the combination of tools used for each of multiple workpieces, and the correspondence relationship between workpieces and groups Depending on the storage means that stores, and the group to which the tool targeted for abnormality detection belongs,
A tool designating unit that designates the tool that is the target of abnormality detection, and a group that determines whether the workpiece to be machined after being designated by the tool designating unit is to be machined by the specified group of tools When the workpiece discriminated by the discriminating means and the group discriminating means is machined by the tool of the designated group for the first time after the designation by the tool designating means, the machining dimension of the machining portion of the workpiece is measured and set. And a tool abnormality detection device for determining that the tool of the group is abnormal when the abnormality is detected by comparing with the dimension and the abnormality is detected.

[Action]

When a new tool is set in the tool magazine, the tool is replaced, or the tool correction amount is changed, the operator designates the group to which the tool belongs by the tool designation means and designates the target tool. After that, the group discrimination means discriminates whether or not the workpiece to be machined is to be machined by the tool of the designated group. Next, when the workpiece discriminated by the group discriminating means is machined by the tool of the designated group for the first time after the designation by the tool designating means, the machining dimension of the machining location of the workpiece is measured to set the set dimension. When the abnormality is detected by comparing with, the tool of the group is determined to be abnormal. The tool abnormality detection device automatically measures the dimension of the processing point when the tool of the specified group processes the workpiece for the first time after the specification. If the machining dimension is within the allowable range with respect to the originally planned machining command value, it is determined that the tool of the designated group is the correct tool planned by the machining program and the tool correction amount is appropriate. To do. On the contrary, when the machining dimension does not exist within the allowable range, it is determined that the tool of the designated group is not a regular tool or the tool correction amount is not appropriate, and the tool abnormality is detected. When no abnormality is detected, the machining program is continued, and when an abnormality is detected, processing such as stopping the machine and notifying the operator is performed.

【Example】

The present invention will be described below based on specific examples. First
In the figure, 10 is a processing device that constitutes the main body of the numerical control device, including a microprocessor MPU, a read-only memory R
It is composed of an OM, a battery-backed non-volatile random access memory RAM1, and a buffer random access memory RAM2. The processing device 10 has a data input device for inputting a machining program or the like.
11, a push button switch 12 as a tool designating means, a pulse generation circuit 13 for supplying a command pulse to the servo motor drive circuits DUX, DUY, DUZ, automatic tool change, contact between the tool and the work W. The contact detection circuit 15 for detecting is connected through an interface (not shown). The abnormality detection device is configured as an internal function of the numerical control device 10, and a program for sequentially instructing an abnormality detection processing procedure of the device is stored in the ROM. On the other hand, 20 is a machining center type machine tool controlled by the numerical controller having the above-mentioned configuration. Reference numeral 25 is a work table that supports a work W, 24 is a headstock that mounts a spindle 26, and the relative positions of the two are servomotors driven by the servomotor drive circuits DUX, DUY, and DUZ, respectively. It is three-dimensionally controlled by the rotation of 21, 22, and 23. Further, 27 is a tool magazine for storing a plurality of types of tools, and a magazine indexing device and a tool changing device (not shown) 28
By this, the specific tool in the tool magazine 27 is selectively mounted on the spindle 26 and the work W is processed. Further, in order to measure the machining dimension, a measuring tool 30 is selected from the tool magazine 27 and mounted on the spindle 26. When the measuring tool 30 is mounted on the spindle 26, the contact detection circuit 15 excites the coil 31. When the measuring tool 30 comes into contact with the wall surface of the processed part of the workpiece W, the measuring tool 3
A closed current path L consisting of 0, the work W, the work table 25, the machine tool base 29, and the headstock 24 is formed.
A secondary current is induced by the change in the magnetic flux penetrating the. Then,
An induced current also flows through the coil 31, the primary conversion resistance of the coil 31 decreases, and it is possible to detect that the measuring tool 30 has come into contact with the wall surface of the machining location due to the change in the resistance. Therefore,
Machining dimensions can be automatically measured by program control from the feed amount until contact between wall surfaces. Next, the operation of the machine of this embodiment will be described. In the present embodiment, the tools are grouped in order to reduce the number of push button switches constituting the tool designating means. First, as shown in FIG. 5, a correspondence table of workpieces and tools to be used is created and grouped by a combination of tools used to machine one workpiece. For example, as shown in FIG. 6, workpieces a and b are tools T1, T3, T5, T6.
Since it is machined by, the set of tools is grouped as A. The set of tools T1, T3, T4 is group B, tool T
A set of 2, T4 and T6 is a C group. When the tool is designated, the group to which the tool belongs is designated.
For example, when the tool T1 is designated, since the tool T1 belongs to both groups A and B, both groups are designated. As shown in FIG. 4, the RAM 2 is provided with a management table for setting a group identification symbol indicating a combination of tools used for each workpiece and a flag for giving a measurement command. Then, according to the operation status of the push button switch 12, all the measurement command flags FLG of the corresponding group are set. In this way, the designation of the tool is input by operating the push button switch corresponding to the group identification symbol. On the other hand, the machining program and the measurement program for each workpiece shown in FIG. 3 are stored in the ROM, and the machining process and the abnormality detection process are executed by selectively executing these programs. In FIG. 2, the microprocessor MPU discriminates the type of the workpiece to be processed and executes the processing program corresponding to the type (100, 102). When the processing is completed, the corresponding measurement command flag FLG is read from the management table in FIG. 4 and its state is determined (104 to 108). In the reset state, since the tool used for machining the workpiece has not been specified, the processing of this execution cycle is ended and the processing of the next workpiece is started. On the other hand, when the flag FLG is set,
Since any of the tools used for the machining of the workpiece has been designated, the measurement program corresponding to the workpiece is read out and executed (110, 112). In the program, it is determined whether or not the measured machining dimension exists within an allowable range with respect to a predetermined command machining dimension, and when it does not exist, an abnormality detection flag is set. The abnormality detection flag is determined in step 114, and if there is an abnormality, processing for notifying the abnormality to the worker is executed (116), and if there is no abnormality, the corresponding measurement command flag FLG is reset and the processing of this execution cycle ends. Then, the processing of the next workpiece is continued. Therefore, after specifying the tool, the abnormality detection process is automatically executed only when the machining using the tool is completed for the first time, and if there is no abnormality, then the abnormality detection process is not performed. Only processing continues.

【The invention's effect】

The present invention is, in a numerically controlled machine tool, a tool designating unit that designates a tool to be an object of abnormality detection by a group to which the tool belongs, and a machining location of a workpiece machined by the tool belonging to the group for the first time after designation. It features a tool abnormality detection device that automatically measures the machining dimension and determines the abnormality by comparing it with the set dimension, and when an abnormality is detected, determines that the tool in that group is abnormal. There is. Therefore, when the tool stored in the tool magazine is replaced or the tool correction amount is changed, if the group to which the tool belongs is designated, whether the tool or the correction amount is appropriate is automatically determined in group units. Therefore, the processing efficiency is increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a numerically controlled machine tool according to a specific embodiment of the present invention, FIG. 2 is a flowchart mainly showing a processing procedure of an abnormality detection device, and FIG.
Arrangement diagram of programs stored in M, FIG. 4 is an explanatory diagram showing a management table for executing a measurement program, and FIGS. 5 and 6 show a method of grouping tools, respectively. FIG. 10 …… Processing device, 20 …… Machine tool, 12 …… Push button switch, 21,22,23 …… Servo motor, 24 …… Spindle head,
25 …… Work table, 26 …… Spindle, 27 …… Tool magazine, 28 …… Tool changer, 30 …… Measuring tool, 31 …… Coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshifumi Honjo 2-1, Toyota-cho, Kariya city, Aichi Stock company Toyota Industries Corporation (56) Reference JP 58-114843 (JP, A) 61-50643 (JP, U)

Claims (1)

[Claims] 1. An automatic tool change function for selecting a commanded tool from a tool magazine containing tools and mounting it on a spindle by program control, and machining a workpiece by mounting a measuring tool on the spindle. In a numerically controlled machine tool that has an automatic dimension measurement function to measure dimensions, the tools are divided into multiple groups according to the combination of tools used for each of multiple workpieces, and the correspondence relationship between workpieces and groups Depending on the storage means that stores, and the group to which the tool targeted for abnormality detection belongs,
A tool designating unit that designates a tool to be an abnormality detection target, and determines whether the workpiece to be machined after being designated by the tool designating unit is to be machined by a designated group of tools. When the group discriminating means and the workpiece discriminated by the group discriminating means are machined for the first time after being designated by the tool designating means by the tool of the designated group, the machining dimension of the machining portion of the workpiece is measured, A numerically controlled machine tool comprising: a tool abnormality detection device that determines an abnormality by making a comparison with a set dimension, and when an abnormality is detected, the tool of the group is determined to be abnormal.