JPH10118890A - Control device of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically and effectively measure the length of a tool whose length is required to be measured in the control device of a machine tool, in the main spindle of which a plurality of tools is selectively secured to perform machining. SOLUTION: Whether measuring the length of the tool T secured in a main spindle 15 based on the command from a machining program is necessary or not is judged, and when it was judged necessary, the length of the tool T is measured. This control device is provided with a memory means to store whether measuring the length of each tool is required or not. The memory contents of the memory means is rewritten so that the measurement of the length of a tool whose length was measured once is omitted when and after the tool is used twice. In addition, this control device is provided with an input device, in which whether or not tool length measurement is required and approximate tool length are input for calculating the tool length from travel amount from the start points of the tool T and the datum face of a reference block to the contact point of the tool T and the datum face by relatively moving the tool T and the datum face of the reference block 12 based on the approximate tool length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a machine tool such as a machining center having a tool magazine having a plurality of tools and an automatic tool changing device for exchanging tools between the tool magazine and a spindle. .

[0002]

2. Description of the Related Art In a machine tool such as a machining center controlled by a numerical controller, in order to perform automatic machining, it is necessary to register a tool length of a tool to be used prior to machining in the numerical controller. The following methods are known for registering the tool length.

One is to measure the tool length outside the machine, and the operator manually inputs the tool length measured by the tool presetter from the operation panel of the numerical control device. Another method is to measure a tool length in a machine tool, and an operator gives a control command from an operation panel of a numerical control device by an MDI operation, so that a tool whose tool length is to be measured is a tool in a tool magazine. The tool was set on the table by indexing to the change position, attaching the tool indexed to this tool change position to the spindle by an automatic tool changer, and further giving an operation command of a program for measuring the tool length. The spindle is moved until it comes into contact with the reference block, the tool length is calculated from the movement amount at this time, and registered in the numerical controller.

[0004]

In the former case, an operator must measure the tool length using a tool presetter. In the latter case, the operator will not directly measure the tool length, but the operator must give control commands such as indexing the tool to be measured to the numerical control device, attaching to the spindle, and measuring the tool length by MDI operation. In any case, manual work by the operator is required.

In the case of the former, since the tool presetter and the machine tool are usually set apart from each other, the operator records the tool length measured by the tool presetter on a data sheet or the like. Key input to the numerical controller while viewing the data sheet may result in human error such as recording error or input error. further,
When measuring the tool length in a machine tool as in the latter, the machining length must be measured before starting the machining operation or by interrupting the machining operation during the machining, resulting in a decrease in work efficiency. .

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to automatically and efficiently measure a tool length. A machine tool control device that selectively mounts a tool on a spindle to perform machining, comprising: a machining program for controlling machining by the machine tool; and necessity of measuring a tool length of a tool selected to be mounted on the spindle. And a tool length measuring means for measuring the tool length of the tool mounted on the spindle according to a command of the machining program when the tool length measurement is determined to be necessary by the determining means. It is characterized by the following.

According to a second aspect of the present invention, there is provided a machining program for controlling machining by a machine tool, storage means for storing in advance the necessity of tool length measurement of a plurality of tools, and a spindle based on the storage means. Determining means for determining whether or not the tool length measurement of the tool selected to be mounted on the spindle is necessary; and determining that the tool mounted on the spindle is required by the processing program command when the tool length measurement is determined to be necessary. Tool length measuring means for measuring the tool length of the tool, and rewriting means for rewriting the storage contents of the storage means so that subsequent tool length measurement of the tool whose tool length has been measured by the tool length measuring means is unnecessary. It is characterized by having.

According to a third aspect of the present invention, there is provided a machining program for controlling machining by a machine tool, and input of necessity of tool length measurement of each tool and an approximate tool length when a plurality of tools are mounted on the machine tool. An input device, a storage unit for storing the necessity of the input tool length measurement and an approximate tool length, and determining whether the tool length measurement of the tool selected to be mounted on the spindle is required based on the storage unit. Means for determining
Tool length measuring means for measuring the tool length of the tool mounted on the spindle according to a command of the machining program when the tool length measurement is required by the determining means, and tool length measuring means for measuring the tool length of the tool. A rewriting means for rewriting the storage content of the storage means so that subsequent tool length measurement of the tool for which the measurement is performed is unnecessary, and a tool information table for storing the tool length measured by the tool length measurement means, The length measuring means has a contact detection function of detecting contact between a tool mounted on the spindle and a reference surface provided on a machine tool, and relatively measures the tool and the reference surface based on an approximate tool length. And the tool length is calculated from the amount of movement until the two come into contact with each other.

Further, the invention according to a fourth aspect is characterized in that the input device is provided in the vicinity of a tool mounting position of a machine tool. A tool information table for storing the tool length measured by the length measuring means is provided, and the tool length is corrected based on the tool length stored in the tool information table.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a machining center 1. A table 11 is provided on a bed 10 so as to be movable in the X-axis direction (perpendicular to the plane of FIG. 1). , A reference block 12 described below is attached. A column 13 is provided on the bed 10 so as to be movable in the Z-axis direction, and a spindle head 14 is provided in the column 13 so as to be movable in the Y-axis direction. Spindle head 14 has spindle 1
5 is rotatably held and driven to rotate by a motor 16. Then, by appropriately controlling the X-axis drive motor 17, the Y-axis drive motor 18, and the Z-axis drive motor 19, the tool T mounted on the tip of the main shaft 15 can be used to move the workpiece W placed on the table 11 Processing is performed. A tool magazine provided with a plurality of tools attached to the main shaft 15 and an automatic tool changing device for exchanging tools between the tool magazine and the main shaft 15 are not shown because a known device may be used.

Here, a contact detection coil 21 connected to an AC power supply 20 via a current detection resistor R is attached to the outer periphery of the tip of the spindle head 14 so as to surround the main shaft 15. Magnetic flux is generated. For this reason, when the tool T contacts the reference block 12, FIG.
, An induced current flows through an induced current circuit as indicated by a broken line, and lowers the impedance of the coil 21. When the impedance of the coil 21 decreases, the exciting current increases and the voltage generated across the resistor R increases, so that a high voltage signal is supplied to the contact detection device 22. The contact detection device 22 detects the contact between the tool T and the reference block 12 based on the increase of the voltage signal. When the contact is detected, a contact detection signal TS is sent to the numerical control device 30 described later. Is done.

As shown in FIG. 2, the numerical controller 30
PU 31 and R as a storage device connected to CPU 31
It comprises a keyboard 35 as an input device connected to the OM 32, a RAM 33 and the CPU 31 via an interface 34, and a CRT 36 as an output device. Here, the RAM 33 stores a tool information table as shown in FIG. The POT number of the tool magazine corresponds to the POT number of the tool magazine.
Stores various data on the tool such as the tool number, the tool length, the tool diameter, and the tool life of the tools stored therein, and these data can be rewritten as necessary. The numerical controller 30 controls machining with reference to these data. The tool length data according to the present invention is based on the tool length data.
Numeral 0 is used to perform tool length correction to correct, for example, the Z-axis command position data in the NC data for the machining program.

The CPU 31 has an interface 3
7, a digital servo unit 38 for driving the X-axis drive motor 17 is connected, and similarly, digital servo units 39 and 40 for driving the Y-axis and Z-axis drive motors 18 and 19 are connected. In addition, each drive motor 1
Encoders 41, 42, and 43 are attached to 7, 18, and 19, respectively, so that current position signals of the drive motors 17, 18, and 19 are fed back to the digital servo units 38, 39, and 40 and the CPU 31. Have been.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG. As shown in FIG. 5, prior to a machining program process in which machining is performed by the machining center, a tool mounting operation is performed. In this tool mounting operation, an operator mounts a tool necessary for machining on a tool magazine. When mounting the tool, as shown in a flowchart of FIG. Gives a tool length measurement instruction and inputs and puts an approximate tool length. Specifically, as shown on the screen of the CRT 36 shown in FIG. 4, “*” is input at a corresponding position of the POT where a tool requiring tool length measurement is mounted, and further, an approximate tool length is input from the keyboard 37. The presence or absence of the input tool length measurement instruction and the approximate tool length are stored in a predetermined area of the RAM 33. Also,
For a tool that does not require tool length measurement, for example, a tool whose tool length is known in advance by being measured by a tool presetter or the like, the tool length is directly input. The directly input tool length is registered in the corresponding area of the tool information table.

Next, the machining program processing will be described with reference to the flowchart shown in FIG. First, after performing various initial processes required for machining in S1, the presence or absence of a T code instructing indexing of a tool magazine is determined in S2. If there is a T code, the indexing process of the tool magazine is performed in S3. Done. In S4, it is determined whether there is an M6 code for instructing a tool change. If there is an M6 code, a tool change process is performed in S5. Then, in S6, processing relating to actual processing such as rapid traverse or cutting feed is performed. In S7, it is determined whether there is an M30 code indicating a program end, and the above processing is repeated until the M30 code appears.

FIG. 8 shows the T code processing in S3.
This will be described based on the flowchart shown in FIG. First, S3
At 0, it is determined whether or not the tool to be indexed to the tool change position of the tool magazine has been instructed to measure the tool length during the previous tool mounting operation. 1 is assigned to the variable # 559, and S3
At 2, the approximate tool length of the tool, which was also input during the tool mounting operation, is substituted into the common variable # 560. Also, S3
If it is 0 and there is no tool length measurement instruction, the process proceeds to S33, and 0 is substituted for the common variable # 559. After these processes are performed, the tool magazine is actually indexed at S34, and the tool specified by the machining program is indexed to the tool change position.

Here, the common variable is used for managing whether or not to perform the tool length measurement, using general-purpose software such as C language, and the tool length measurement processing for actually measuring the tool length is a numerical value. This is because the control is performed by the macro program of the control device 30, and a common variable is used as a data transfer means between the general-purpose software and the macro program.

Next, M6 of S5 of the above machining program processing
The code processing will be described with reference to FIG. First,
In S50, the automatic tool changer performs the exchange between the tool indexed to the tool exchange position of the tool magazine in the T-code processing and the tool mounted on the spindle 15.
Then, in S51, it is determined whether or not the common variable # 559 is 1, that is, whether or not it is necessary to measure the tool length. If there is no instruction to measure the tool length, the M6 code processing is terminated, and If there is a length measurement instruction, a tool length measurement process described later is performed in S52. When the tool length measurement processing is completed, the process proceeds to S53, where the measured tool length is stored in a corresponding area of the tool information table. next,
At S54, the tool length measurement instruction is turned off, and at S55, the approximate tool length is set to 0. As a result, once the tool is measured, the tool length is not performed in the second and subsequent use.

Next, the tool length measuring process in S52 of the M6 code process will be described with reference to the flowchart of FIG.
1 will be described. First, in S520, the spindle 15 on which the tool T is mounted is moved to a predetermined measurement start position SP. Then, the current value of the Z-axis at the measurement start position SP is read, and this value is substituted for B. Here, since the position of the reference surface 44 of the reference block 12 on the table 11 in the Z-axis direction does not change, the reference position of the spindle 15 at the measurement start position SP, for example, between the end surface of the spindle and the reference block 12 on the table 11. The distance from the reference plane 44 is known, and this distance is defined as L. Next, although not fast forward the Z-axis at S522, the feed amount l ₁ at this time is determined as follows.

L ₁ = L − (# 560 + 50 mm) That is, the approximate tool length (common) is calculated from the distance (L) between the reference position of the spindle 15 at the measurement start position SP and the reference surface 44 of the reference block 12 on the table 11. Variable # 560
) And a margin value (50 m in the above equation).
m) is subtracted.

Next, in step S523, the feed speed of the Z axis is set to a low speed, and the slow feed (feed amount l ₂ ) of the Z axis is continued until the contact between the tool T and the reference block 12 is detected in step S524. When the tool T comes into contact with the reference surface 44 of the reference block 12, the contact detection device 22 outputs a contact detection signal TS. This contact detection signal TS is output to interface 4
When input to the CPU 31 of the numerical control device 30 via 6, the CPU 31 stops the Z-axis feed (S 525), reads the current value of the Z-axis at this stop position, and substitutes this value for C. (S526) Note that S523 and S5
The process in 24 is normally called skip feeding, and has a function of instructing movement to a certain point behind (to the left in FIG. 11) from the reference plane 44, but stopping movement by the contact detection signal TS. In addition, reference numeral 45 in FIG. 11 denotes a spring, which
And to prevent breakage of the tool T. Here, in the contact detection method described above, the approximate tool length is input, and the rapid feed amount of the spindle 15 at the time of contact detection is determined based on the approximate tool length. As disclosed in JP-B-61-58263, the tool T is brought into contact with the reference surface 44 of the reference block 12 at a rapid traverse, the spindle 14 is retracted once until the contact signal is turned off, and the tool T is again moved at a slow traverse. If a contact detection method that makes contact with the reference surface 44 is used, accurate contact detection can be performed in a short time without inputting the approximate tool length.

Next, in S527, the Z axis is returned to the original position.
At 528, the tool length is calculated. That is, the tool length X is obtained by the following equation. X = L− | B−C | Then, in S529, the tool length X is stored in the measurement data storage area of the RAM 33, and the tool length measurement processing ends. Here, the tool length X stored in the measurement data storage area in S529 is stored in a predetermined area of the tool information table in S53 in the M6 code processing of FIG. 9 described above, and is used for tool length correction in subsequent machining. Used.

In the above embodiment, a tool information table is provided in the RAM 33 of the numerical controller 30.
Each process is performed by the CPU 31 of the numerical controller 30. A computer for tool management is provided separately from the numerical controller 30, and a tool information table is stored in the tool management computer. Necessary data may be transferred to and from a computer.

Further, as another embodiment, a tool setup operation panel as shown in FIG. 12 can be provided. In a normal machining center, the mounting of a tool is performed from the rear or side of the tool magazine, and the tool length measurement instruction is performed from an operation panel on the front of the machining center, so that there is a problem that workability is poor. However, as shown in FIG. 12, the tool setup operation panel 47 provided near the tool mounting location of the tool magazine is provided with input means for the presence or absence of a tool length measurement instruction and the approximate tool length. Thus, at the same time when the tool is mounted on the tool magazine, the presence or absence of the tool length measurement is selected by the changeover switch 48, the approximate tool length is inputted by the digital switch 49, and the tool mounting button 5
Press 0. With this configuration,
The workability of the tool mounting operation is improved, and the presence / absence of a tool length measurement instruction and the input error of the approximate tool length are reduced.

Further, another embodiment can be configured as follows. That is, in the above embodiment, the tool length measurement instruction is turned off after the tool length measurement in S54 of the flowchart shown in FIG. 9, so that the tool length measurement is performed when the tool is used for the second and subsequent times. Not configured. However, when high-precision machining is required, for example, the tool usage time is integrated, and when the integrated tool usage time exceeds a predetermined time, the tool length measurement instruction is turned ON, and the tool length measurement is performed again. If the configuration is such that the tool length is updated, it is possible to perform tool length correction in consideration of a change in the tool length due to tool wear.

[0026]

According to the first aspect of the present invention, when a tool determined to require tool length measurement is mounted on a spindle according to a command of a machining program, the tool length measurement of the tool is performed. Tool length measurement by hand or M
There is no need to issue a tool length measurement instruction by DI operation,
In addition, an input error of the tool length is prevented. Furthermore, since the tool length measurement is performed prior to machining when the tool is mounted on the spindle for use in machining, it is not necessary to change tools only for tool length measurement, and efficient work can be performed. Can be.

According to the second aspect of the present invention, in addition to the above effects, the stored contents of the storage means are rewritten so that the tool length correction of the tool whose tool length has been measured once is unnecessary. In the second and subsequent uses, the tool length measurement is not performed, so that there is an effect that more efficient work can be performed. According to the third aspect of the invention, in addition to the above effects, the tool length is measured by detecting the contact between the tool and the reference surface, so that the accurate tool length can be measured. Further, at the time of this contact detection, the feed amount for bringing the tool into contact with the reference surface is determined based on the approximate tool length, so that the tool length measurement time can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram showing a machining center and a contact detection device according to the present invention.

FIG. 2 is a block diagram illustrating a numerical control device according to the present invention.

FIG. 3 is a diagram showing a tool information table.

FIG. 4 is a view showing a tool length measurement instruction screen of the CRT.

FIG. 5 is a flowchart showing a work flow of the present invention.

FIG. 6 is a flowchart showing a tool mounting operation.

FIG. 7 is a flowchart showing a machining program process.

FIG. 8 is a flowchart showing T code processing.

FIG. 9 is a flowchart showing M6 code processing.

FIG. 10 is a flowchart illustrating a tool length measurement process.

FIG. 11 is a diagram showing a relationship between a tool and a reference block.

FIG. 12 is a view showing a tool setup operation panel according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machining center 12 Reference block 15 Spindle 21 Coil 20 AC power supply 22 Contact detection device 30 Numerical control device 33 RAM 44 Reference surface 47 Tool setup operation panel T Tool

Claims (5)

[Claims] 1. A control device for a machine tool for performing machining by selectively mounting a plurality of tools on a spindle, the machining program controlling machining by the machine tool, and a machine program selected to be mounted on the spindle. Determining means for determining whether or not tool length measurement of a tool is necessary; and determining that the tool mounted on the spindle by the command of the machining program requires tool length measurement by the determining means, the tool length of the tool is determined. A control device for a machine tool, comprising: a tool length measuring means for measuring. 2. A control device for a machine tool for performing machining by selectively mounting a plurality of tools on a spindle, comprising: a machining program for controlling machining by the machine tool; and a tool length measurement of the plurality of tools in advance. Storage means for storing the necessity of the tool, determination means for determining whether or not tool length measurement of a tool selected to be mounted on the spindle is necessary based on the storage means, and mounting to the spindle according to a command of the machining program. Tool length measurement means for measuring the tool length of the tool when the tool length measurement is determined to be necessary by the determination means, and after the tool whose tool length has been measured by the tool length measurement means A control device for a machine tool, comprising: rewriting means for rewriting the storage contents of the storage means so that the tool length measurement is not required. 3. A control device for a machine tool for performing machining by selectively mounting a plurality of tools on a spindle, comprising: a machining program for controlling machining by the machine tool; An input device for inputting the necessity of the tool length measurement of each tool and the approximate tool length at the time of mounting, storage means for storing the necessity of the tool length measurement and the approximate tool length inputted, and the main spindle based on the storage means Determining means for determining whether or not tool length measurement of a tool selected to be mounted on the tool is necessary, and determining that the tool mounted on the main spindle requires tool length measurement by a command of the machining program. A tool length measuring means for measuring a tool length of the tool; and a rewriting for rewriting contents stored in the storage means so that subsequent tool length measurement of the tool whose tool length has been measured by the tool length measuring means is unnecessary. With means The tool length measuring means has a contact detection function of detecting contact between a tool mounted on the spindle and a reference surface provided on a machine tool, and based on the approximate tool length, the tool and the reference surface And a tool length is calculated from a moving amount until the two come into contact with each other. 4. The machine tool control device according to claim 3, wherein the input device is provided near a tool mounting position of the machine tool. 5. The control device for a machine tool according to claim 1, further comprising a tool information table for storing a tool length measured by said tool length measuring means, wherein said tool information is stored in said tool information table. A machine tool control device for performing a tool length correction based on a length.