JPH11282518A - Machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machine tool for changing a servo parameter according to a working condition. SOLUTION: Relating to a machine tool controller 21, optimal servo parameters 24a and 24b are selected from an RAM 24 based on the tool diameter of a tool to be exchanged the next, and each of axial servo motors 6, 13, 15, and 18 is controlled by a servo amplifier 27 by using the selected servo parameters 24a and 24b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool capable of performing desired machining by controlling a motor.

[0002]

2. Description of the Related Art Conventionally, in order to control a servomotor for driving a feed shaft of a machine tool, an industrial machine, or the like, a robot arm, or the like, it is necessary to set appropriate servo parameters of a servo control system including a servomotor. was there. These servo parameters are parameters that determine the response of a speed loop or the like, and need to be adjusted according to the control target. The response of the servo control system is determined, and various servo parameters are adjusted based on the measurement results.

[0003] Among the objects to be controlled are main spindles, and tools mounted on the main spindles are roughly classified into large diameter tools and small diameter tools. Conventionally, when the shape of the tool is different, the servo parameters are adjusted and set so as to satisfy even the worst conditions. Also, the set servo parameters are fixed for each device of the servo control system,
Could not be changed.

[0004]

If the servo parameters are adjusted and set to satisfy even the worst conditions as in the prior art, the response of the servo control system is poor and the stability is also poor. .

[0005] Therefore, there is a problem that the processing time becomes long.

As a method of solving this, it is conceivable to set the adjustment of the servo parameter to an intermediate value between the worst condition and the best condition. If machining is performed at the same speed or the like, there is a problem in that vibration of the main shaft, resonance noise of the main shaft, and the like are generated, and tap accuracy is reduced.

[0007] The present invention has been made to solve the above-described problems, and has as its object to provide a machine tool capable of changing servo parameters according to processing conditions.

[0008]

In order to achieve this object, a machine tool according to the present invention is intended for controlling a motor in accordance with machining data to perform desired machining, and particularly for controlling the motor. Storage means for storing a plurality of parameters such as gain and time constant necessary for each item such as the gain and time constant, and a plurality of parameters for each item stored in the storage means based on the processing data. And a control means for controlling the motor using the parameters selected by the selection means.

Therefore, an optimum parameter based on the processing data is selected from the storage means by the selection means, and the motor is controlled by the control means using the selected parameter. Motor responsiveness and stability can be obtained.

In the machine tool according to the present invention, the machining data includes information on a tool such as a tool diameter and a tool weight.

Therefore, the selection means selects one parameter from the storage means according to the diameter and weight of the tool to be used, and controls the motor using the parameter, so that the selection means is suitable for the tool being used. Processing can be performed.

Further, in the machine tool according to the third aspect, the selection means selects the current tool mounted on the spindle and the next tool to be replaced only when the type is different.

Therefore, when there is no change in the tool diameter or the tool weight between the current tool and the next tool to be used, the trouble of selecting the same parameter from the storage means can be omitted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A machine tool according to an embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 3 shows an external configuration of a main part of a machine tool according to the present embodiment.

Here, a column 3 is provided on the base 2 so as to extend upward. A linear guide 4 extending in the vertical direction is provided on the front surface of the column 3, and along the linear guide 4. The headstock 5 is supported to be vertically movable.

The column 3 is provided with a Z-axis servomotor 6 and a ball screw mechanism (only the ball screw 7 is shown) for freely moving the headstock 5 in the vertical direction. At the front of the base 2, a work (not shown) is set, and an XY table 8 is provided for freely moving the work in the XY directions.

The headstock 5 is provided with a machining head 9 and a rotary tool magazine 10 and a tool changing device 11. The machining head 9 has a spindle 12 at a lower portion thereof, and a spindle 12 at an upper portion thereof.
And a main shaft servomotor 13 for rotating the motor. A tool 14 is detachably attached to the main shaft 12.

Thus, the machining head 9 is moved up and down by driving the Z-axis servo motor 6 while rotating the tool 14 attached to the main shaft 12, and the X head is moved together with the X-axis servo motor 6.
When the work set on the Y table 8 is moved in the horizontal direction, processing on the work is performed. At this time, the XY table 8, Z
The shaft servomotor 6, the spindle servomotor 13 and the like are shown in FIG.
Is controlled by the control device 21 shown in FIG.

The tool magazine 10 has a plurality of tool pots (not shown) capable of storing the tools 14 arranged in a ring shape. When the magazine servo motor 15 drives the necessary tool pots (the tools 14), It is configured to be located at the lowermost tool access position. Then, the tool changer 11 exchanges the tool 14 stored in the tool pot at the tool insertion / removal position with the tool 14 attached to the main shaft 12 (when only one of the tools 14 is provided, The tool 14 is transferred to the other).

The tool changing device 11 includes a tool changing arm 16 for performing a tool changing operation, a tool changing cam (not shown) for operating the tool changing arm 16 by rotational driving, and a driving for rotating the tool changing cam. The servo motor 18 is provided.

The tool change arm 16 is located at an intermediate portion between the tool access position of the tool magazine 10 and the spindle 12 and extends so as to sandwich an arm support 20 provided below the headstock 5. A grip portion (not shown) for gripping and transporting the tool 14 is provided at both ends thereof in a point-symmetric manner.

Next, a control device 21 for controlling a machine tool according to the present embodiment will be described with reference to the block diagram of FIG.

The control device 21 includes a CPU 22 and an RO
M23, a RAM 24 as storage means, an interface (INT) 25, an axis control circuit 26, and a servo amplifier 27 as control means.

The CPU 22 is a processor that controls the control device 21 as a whole, reads a main program stored in the ROM 23 via a bus 29, and controls the control device 21 as a whole according to the main program. doing.

The ROM 23 stores a main program for controlling the control device 21 as a whole. The main program includes a program for judging the shape of the tool 14 mounted on the spindle and parameters for the servo amplifier 27. A program for executing processing for switching servo parameters is also stored.

The RAM 24 is a magazine in which temporary calculation data and display data and various data input by an operator via the operation panel 28 are set, in which a large-diameter tool or a small-diameter tool is set for each tool. There is a tool number data area 24c. Servo parameters required for servo control are also stored, and servo parameters 24a and 24b for the large-diameter tool and the small-diameter tool are stored in advance.

The interface 25 transmits a data signal from an external device connectable to the control device 21 to the C signal.
It serves to pass data to the PU 22, the ROM 23, the RAM 24, and the like.

The operation panel 28 includes a CP (not shown).
This is a manual data input device including a U, a memory, a display, a keyboard, and the like, which performs a display process based on data sent from the CPU 22 via the interface 25 and displays the data on the display.

The axis control circuit 26 receives a speed command or a movement command for each axis from the CPU 22 and outputs it to the servo amplifier 27 for each axis. The servo amplifier 27
Receives this command and drives each axis servomotor 6, 13, 15, 18 of the machine tool based on the servo parameter setting value in the servo parameter storage area 27a described later.

The servo amplifier 27 is provided with a servo parameter storage area 27a.
It can be sequentially updated by the servo parameters sent from the RAM 24 in response to a command from U22.

Table 1 below is a table showing differences in optimum servo parameters depending on the tool shape. The servo parameters in the present embodiment are parameters that determine the response characteristics of the servo control system, such as a notch filter, a gain, and a time constant.

[0033]

[Table 1]

The notch filter is a filter capable of attenuating, that is, removing around a specific frequency. The tool 14 may cause resonance at a certain frequency, and the resonance frequency differs depending on the tool shape.
For example, as shown in Table 1, a small-diameter tool has a higher resonance frequency than a large-diameter tool, and conversely, a large-diameter tool has a lower resonance frequency. Conventionally, none of the tools could be satisfied because the servo parameters were fixed for each control device 21. However, since the set values of the notch filter and the like can be changed for each tool, the resonance frequency can be changed for any tool. Can be eliminated, and the vibration and noise of the machine can be reduced.

Similarly, it is desirable to change the gain and the time constant according to the tool shape (large-diameter tool, small-diameter tool).

Next, the operation of changing the servo parameters according to the present invention will be described with reference to the block diagram of FIG. 2 and the flowchart of FIG. In addition, the flowchart of FIG.
This is executed when the operation of tool change is started.

First, the tool number of the tool 14 currently mounted on the main spindle is searched from the magazine tool number data area 24c in the RAM 24 of FIG. 2, and the tool mounted on the main spindle is searched from the tool number. It is determined whether or not 14 is a large-diameter tool (step 1, hereinafter, steps are represented by S). In S1, if the tool 14 mounted on the spindle is a large-diameter tool (YES in S1), it is determined from the magazine tool number data area 13c whether the next tool 14 to be replaced is a large-diameter tool. Then, if the tool 14 to be replaced next is also a large-diameter tool (YES in S2), since the tool shape is the same after the tool replacement, the processing for sending servo parameters to the servo amplifier 27 is not performed and the process ends. I do.

In the processing step of S2, if the next tool to be replaced is a small-diameter tool (NO in S2),
Since the shape of the tool 14 differs before and after the tool change, the RAM 24
Then, the servo parameters 24b for the small-diameter tool are sent to the servo amplifier 27, and the data in the servo parameter storage area 27a of the servo amplifier 27 is updated (S3).

On the other hand, if it is determined in the processing step S1 that the tool 14 mounted on the spindle is not a large-diameter tool (NO in S1), it is determined whether the tool 14 to be replaced next is a large-diameter tool. If it is determined (S4) that the tool is not a large-diameter tool (NO in S4), since the tool shape does not change even after the tool change, the process ends without sending the servo parameters to the servo amplifier 27. I do. In the process of S4, when it is determined that the tool 14 to be replaced next is a large-diameter tool (YES in S4), the tool 1 is changed before and after the tool replacement.
Since the shape of No. 4 is different, the servo parameter 24a for the large diameter tool in the RAM 24 is sent to the servo amplifier 27, the data in the servo parameter storage area 27a of the servo amplifier 27 is updated (S5), and the process is terminated.

In the above-described tool changing process, the relationship between the size of the tool 14 on the spindle side, the size of the tool 14 to be changed next, and the servo parameter switching operation from the RAM 24 to the servo amplifier 27 is as shown in Table 2. is there.

[0041]

[Table 2]

As is clear from the above description, the machine tool according to the present embodiment sets the optimum servo parameters 24a and 24b to RA based on the tool diameter of the tool 14 to be replaced next.
M24, the servo motors 6, 13, 15, and 18 are controlled by the servo amplifier 27 using the selected servo parameters 24a and 24b.
Motor responsiveness and stability according to the processing data can be obtained, and vibration, noise, accuracy, and the like of the machine tool can be improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in this embodiment, when the servo parameters are switched, the servo parameters 24a for the large-diameter tool or the servo parameters 24b for the small-diameter tool stored in the RAM 24 are stored in the servo amplifier 27.
The switching is realized by sending the data to the servo parameter storage area 27a and updating the servo parameters.
As another method, the servo parameters 24a and 24b for the large-diameter tool and the small-diameter tool are stored in the servo parameter storage area 27a of the servo amplifier 27 in advance, and when the servo parameters are switched, the servo parameters are stored in the servo parameter storage area 27a. Two types of servo parameters are assigned to CPU2
Alternatively, either one may be selected by a command from the second.

In this embodiment, the servo parameters are selected by using the shape of the tool, for example, the tool diameter, as the processing data. However, the weight of the tool, the material of the work, the processing method (drill, Tap or the like).

Further, in the present embodiment, it has been described that the servo parameter switching process is automatically performed when the tool changing operation is started. However, a servo parameter switching switch is arranged on the operation panel 28 in advance, and the operator performs the switching. A switch may be used so that the servo parameters can be directly switched at any time.

Further, in the machine tool of the present embodiment, the servo parameters 24a for the large-diameter tool are used as the servo parameters.
And a small-diameter tool servo parameter 24b, and all the parameters are used. However, it may be configured such that only a specific item, for example, only the gain can be changed.

[0047]

As is apparent from the above description, in the machine tool according to the first aspect, the selection means selects an optimum parameter based on the processing data from the storage means, and stores the selected parameter. Since the motor is controlled by the control unit using the motor, motor responsiveness and stability according to the processing data can be obtained.

Further, in the machine tool according to the second aspect, the selection means selects one parameter from the storage means according to the diameter and weight of the tool to be used, and the control means uses the parameter to control the selection means. Since the motor is controlled, machining suitable for the tool being used can be performed.

Further, in the machine tool according to the third aspect, when there is no change in the tool diameter, the tool weight, and the like between the current tool and the next tool to be used, the same parameter is selected from the storage means. It is possible to obtain effects such as saving labor.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the operation of the present embodiment.

FIG. 2 is a block diagram showing an electric circuit of the machine tool according to the embodiment.

FIG. 3 is a perspective view showing the entire machine tool of the present embodiment.

[Explanation of symbols]

 6 Z-axis servo motor 13 Spindle servo motor 15 Magazine servo motor 18 Drive servo motor 22 CPU 23 ROM 24 RAM 24a Servo parameters for large-diameter tool 24b Servo parameters for small-diameter tool 27 Servo amplifier

Claims (3)

[Claims] 1. A machine tool for controlling a motor according to machining data to perform desired machining, wherein a plurality of parameters such as a gain and a time constant necessary for controlling the motor are provided for each of the items such as the gain and the time constant. A storage unit that stores, a selection unit that selects one of a plurality of parameters for each item stored in the storage unit based on the processing data, and a motor that uses the parameter selected by the selection unit. And a control means for controlling the machine tool. 2. The machine tool according to claim 1, wherein the machining data includes information on a tool such as a tool diameter and a tool weight. 3. The machine tool according to claim 1, wherein said selecting means selects only when the type of the current tool mounted on the spindle and the type of the next tool to be replaced are different. .