JPH0819939A - Monitor for machining load - Google Patents

Abstract

PURPOSE:To precisely grasp a machining load and to easily monitor breakage and abrasion of a tool in a monitor of the machining load in a machine tool. CONSTITUTION:Load detection devices 21-24 of motors 1-4 of a machine tool, arithmetic processing units 16A-C of detection data, a graphic display means 31 and a monitor 11 for display are furnished', and when selection of a new tool is commanded from a machining program of an NC device to control the machine tool, the arithmetic processing unit 16C gives a scope erasion command to the graphic display means 31. Additionally, when selection of a new tool is commanded from a memory 32 to store a monitoring area designation file consisting of a plural number of records containing the upper limit values of a tool ID and a load and the machining program of the NC device to control the machine tool, a record containing the new tool ID is retrieved from the monitoring area designation file, and when the record to be an object to be retrieved exists, the upper limit value of the load of the record is given to comparators 17A, 17B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine load monitoring (including display monitoring) device for a machine tool.

[0002]

2. Description of the Related Art In a normal NC machine tool, a machining load is measured in order to detect breakage of a tool or the arrival of a tool life during machining. Recent NC devices have a monitor, and the measured load is displayed graphically on the monitor. Furthermore, the operator can specify a specific processing section and instruct automatic load monitoring. When performing this automatic load monitoring, the operator sets the monitoring section and the upper limit of the allowable load. Work is needed.

In the graph display of the machining load in this type of load monitoring apparatus, the horizontal axis represents time and the vertical axis represents load, and the load fluctuations of the spindle motor and the feed motor from the start to the end of machining the work are displayed in a graph. That is.

When the operator sets the processing load automatic monitoring section, the monitoring start time (elapsed time from the start of processing) and the end time are input to determine whether the motor to be monitored is a motor (for example, a spindle motor). Z-axis feed motor) and the upper limit of load. In machining performed while turret indexing or tool conversion by ATC, it is often necessary to set a plurality of load monitoring sections during machining of one workpiece.

[0005]

In the graph display of the machining load of the above-mentioned conventional apparatus, when the work is complicated and the machining time is long, the graph displayed on the monitor is compressed in the time axis direction, and each tool used. It becomes difficult to understand the minute fluctuations in the machining load. In addition, when large and small tools are used, the machining load when machining with a small tool (for example, a thin boring tool or small diameter drill) is only displayed small on the graph, making it difficult to understand the load fluctuation. , It becomes virtually unrecognizable. Therefore, even if such a small tool is broken or worn, it is almost impossible for the operator to recognize the occurrence of such a failure from the displayed graph.

Further, in the conventional automatic load monitoring, the operator must set the start and end of the load monitoring section for each individual monitoring section, and the section setting work is also performed during the entire machining process of the workpiece. Since it was necessary to set a specific section of by the elapsed time from the start of machining,
It is very difficult to understand what value should be input as the section setting value. In addition, the setting work is very complicated and time-consuming, such as checking what kind of tool is used at each time during machining and how to select the motor to be monitored in a machine tool with many control axes. However, there is a problem in that setting errors are likely to occur.

Therefore, although many NC devices have an automatic motor load monitoring function, there are many cases where machining is performed without using the automatic load monitoring function.

An object of the present invention is to make it possible to more accurately recognize a machining load during machining and monitor breakage or wear of a tool more easily.

[0009]

In order to solve the above problems, a machining load monitoring apparatus of the present invention is a load detecting apparatus 21 to 24 for motors 1 to 4 equipped on a machine tool and an arithmetic processing unit 16A for detected data. , 16B and 16C, a graph display means 31, and a display monitor 11, and when a new tool selection is instructed from a machining program of an NC device for controlling a machine tool, the arithmetic processing device 16C displays a graph. It is characterized in that a screen erasing command is given to the means 31.

Further, the arithmetic processing units 16A, 16B, 16
Comparing the detection value of the load obtained by the calculation processing of C with the set upper limit value, comparators 17A, 17B are provided, and when it is detected that the detection value is larger than the upper limit value, the NC device detects the overload. In the structure of giving a signal, the tool I
When a new tool selection is instructed by a memory 32 that stores a monitoring section designation file including a plurality of records including D and an upper limit value of the load, and a machining program of an NC device that controls a machine tool, the new tool selection It is characterized in that a record including a different tool ID is searched from the monitoring section designation file, and when the record to be searched exists, the upper limit value of the load of the record is given to the comparator 17.

Furthermore, a memory 32 for storing the maximum value of the load detected during machining together with the tool ID of the tool used for machining, a data input device 35, a monitor 11 for displaying data, and a monitoring section designation file. Input screen display means 34 for displaying the record input screen of FIG.
6C, and the data input device 35 when the data input screen is displayed on the monitor 34.
When the tool ID and the motor ID are input from, the arithmetic processing unit 16C reads the maximum value of the load detection value of the motor when the tool is used from the stored data of the memory 32 and displays it on the monitor 11. And

[0012]

The main reason why the machining load needs to be monitored is to detect breakage or wear of the tool. In the load monitoring apparatus of the present invention, the monitor (which can be detected by the T code of the machining program) is cleared every time a new tool is selected by indexing the tool turret or the like, and redrawing of a new graph is started. Therefore, the graph displayed on the monitor is updated every time the tool is changed, and it is possible to display in detail what kind of load is being applied to each tool. Can accurately recognize fluctuations.

The scale of the horizontal axis and the vertical axis when redrawing the graph is set by first starting the drawing using the default scale and automatically changing the scale according to the detected value. An appropriate scale is selected according to the size. Such automatic selection of the vertical and horizontal scales of the graph has been conventionally performed, and in such an apparatus, the vertical and horizontal scales of the graph are automatically set to default values when redrawing of the graph is started.

Further, as the vertical scale setting of the graph, an appropriate scale setting can be performed by using the upper limit value set in the record of the monitoring section designation file.

In the monitoring apparatus according to the second aspect of the present invention, the automatic load monitoring section is set by designating the type of tool and the type of motor during setup work. That is, by specifying the tool ID (T code in the normal NC program) of the tool to be monitored, when machining using that tool is started, automatic load monitoring is started and use of that tool is completed. Then, the automatic load monitoring also automatically ends. Even when automatic load monitoring is required for multiple tools, the operator only needs to register a record containing the tool IDs of the required tools in the monitoring section setting file, so tool replacement is frequently performed and a large number of tools are required. Even in the machining of complex workpieces where is used, the automatic monitoring section can be set easily.

Further, in the apparatus according to the third aspect, when a plurality of the same workpieces are continuously machined, the test machining is performed by using a new tool whose blade edge is not worn, and then the operator sets the automatic monitoring section. When the input screen is opened on the screen, the maximum load value for each tool during test machining is displayed, so the operator can set the upper limit value of the load by referring to that value and set the automatic monitoring section. It becomes possible to easily and accurately set the upper limit value (when the load exceeds this value, the machine is stopped because tool breakage or the like has occurred).

By displaying the input screen on the monitor after machining several workpieces, the maximum value of the load at the time of test machining (the value at which the tool cutting edge is not worn) and the current machining (for the tool) is displayed. It is also possible to grasp the wear state of the tool to be monitored by looking at the difference between the fact that wear has occurred and the processing load has increased.

[0018]

FIG. 2 shows an embodiment in which the present invention is applied to an NC turret lathe equipped with a rotary tool. As shown in FIG. 2, an NC turret lathe capable of using a rotary tool has four motors including a spindle motor 1, a Z-axis feed motor 2, an X-axis feed motor 3 and a milling motor 4 (in addition, an indexing motor for the spindle 6 and It also has an indexing motor for the turret 5 and the like, but it is omitted because it is not directly related to the present invention.
For driving, for example, cylindrical machining, for driving the spindle motor 1 and the X-axis feed motor 3, for example, end face machining, for driving the milling motor 4 and the Z-axis feed motor 2, for example, key groove machining, milling. The motor 4 and the X-axis feed motor 3 are driven to perform, for example, drilling in the direction perpendicular to the workpiece axis.

As shown in FIG. 1, the load monitoring apparatus is provided with two processing systems A and B (actually, one hardware is used for time sharing), and the monitor 11 is as shown in FIG. The loads of the two axes A and B are displayed at the same time.
An X-axis feed motor 3 and a Z-axis feed motor 2 are connected to the processing system A, and either one of them is displayed and monitored by the switch circuit 12A. A spindle motor 1 and a milling motor 4 are connected to the processing system B,
Either one is set as a display and monitoring target by the switch circuit 12B.

The power supply circuit of each motor 1, 2, 3, 4 includes:
Current detectors 21, 22, 23, 24 for load detection are provided, and their detection signals are AD converters 13,
Switch circuits 12A, 1 via the input interface 14
It is input to 2B. Switch circuits 12A, 12B
Is the T of the machining program of the NC device 15, as will be described later.
Based on the code, X-axis feed motor 3 and Z-axis feed motor 2
And one of them, the spindle motor 1 and the milling motor 4
The load data of either one of
Enter in 16B. The arithmetic processing units 16A and 16B convert the input detection data into loads (wattage) and give them to the comparators 17A and 17B. The comparators 17A and 17B are
The upper limit values set in the respective upper limit value buffers 18A and 18B are compared with the detection value input from the arithmetic processing unit, and when the detection value exceeds the upper limit value, an overload signal is output. When an overload signal is output from either one of the two comparators 17A and 17B, the overload signal is given to the NC device 15 via the OR circuit 19, and the NC device follows the emergency program registered in advance. Stop the device.

The load values calculated by the arithmetic processing units 16A and 16B are given to the graph display unit 31 and the monitor 11 is operated.
Line graphs A and B are displayed as shown in FIG.

FIG. 1 shows three arithmetic processing units 16A and 16A.
Although the B, 16C and the NC device 15 are displayed in different blocks, in reality, the arithmetic processing devices 16A, 16B, 1
6C is an arithmetic processing unit of the NC device 15. Therefore, the arithmetic processing units 16A and 16B determine whether the rotational speeds of the motors 1, 2, 3, 4 and the feed motors 2 and 3 are in the fast feed state or the cutting feed state. I am aware of The comparators 17A and 17
The sending of the detected value to B is started in the feed motors 2 and 3 after the cutting feed of the motor, and the rotation speeds of the spindle motor 1 and the milling motor 4 are the designated rotation speeds. The number is reached and the rotation of the feed motor 2 or 3 is given after the cutting feed. This prevents the momentary load at the start-up of the motor and the load at the time of tool rapid feed from being compared with the upper limit value to output an erroneous overload signal.

When the T code is read from the machining program into the NC unit 15, the arithmetic processing unit 16C (which is the arithmetic processing unit of the NC unit) uses the T code to store in the memory 32.
If there is a record with a matching T code, the switch circuit 1 is searched based on the designation of the monitored motor registered in the record.
Switch between 2A and 12B. In addition, the upper limit value registered in the record is set in the upper limit value buffers 18A and 18B. Further, the arithmetic processing unit 16C uses the machining program
When the code is read, the maximum value buffer 33A, 33
The value of B is written in the memory 32 and then cleared, and the monitor display erase signal is sent to the graph display device 31.

The above-mentioned processing is performed according to the procedure shown in FIGS. Here, the flowchart shown in FIG. 4 is the processing performed by the arithmetic processing device 16C, and the processing shown in FIG. 5 is the processing performed by the arithmetic processing devices 16A and 16B and the graph display device 31 (the arithmetic processing Each of the devices 16A, 16B, and 16C is an arithmetic unit of an NC device, and is shown as a separate block in Fig. 1 for convenience of explanation, and therefore, the program shown in the flowchart of Fig. 4 and the program shown in the flowchart of Fig. 5. And are run in parallel or sequentially as needed).

The processing shown in FIG. 4 is executed in the form of an interrupt program when the NC device reads the T code from the machining program. First, it is confirmed whether or not the monitoring section designation file exists, and if the monitoring section designation file does not exist (that is, if no tool is a monitoring target tool), a graph deletion flag is set and the process ends. On the other hand, when the monitoring section designation file exists, the data of the maximum value buffers 33A and 33B is stored in the memory 32, and whether or not the read T code is the monitoring target is searched for the T code of the monitoring section designation file. Confirm. If the corresponding T code is not the monitoring target, the graph erase flag is set and the interrupt program is terminated. If it is a monitoring target, the upper limit value set in the retrieved record is set to the upper limit value buffer 18
A and 18B are set, and the switch circuits 12A and 12B are switched according to the designation of the motor to be monitored in the record to end the interrupt program.

On the other hand, the program shown in the flowchart of FIG. 5 is repeatedly executed at set time intervals during machining of the work. At each execution, first, it is checked by the interrupt program of FIG. 4 whether the graph erasing flag is set, and if the flag is not set, load calculation is performed,
Add a new plot to the graph. As a result, lines A and B are drawn on the monitor 11 as shown in FIG. On the other hand, if there is a graph deletion flag, clear the monitor screen,
Perform load calculation and display the first plot after clearing.

To set the automatic load monitoring section, that is, to register the record in the monitoring section designation file, the input screen display means 34 displays the input screen as shown in FIG. 6 on the monitor 11, and the data input means such as a keyboard. Through 35. FIG. 6 shows a screen when the setting of the tools of T codes 0101 and 0303 is performed after the test machining of the work. In the setting of T code 0101, the Z-axis feed motor is selected as the motor to be monitored (cylindrical machining), and the maximum load value of the motor when the test machining is performed is the memory 32 as the initial value and the machining value.
Read from and displayed automatically. Therefore, the operator refers to these values and sets the damage value. Similarly, for the data of the tool code 0303, the motor to be monitored is designated, and the damage value is set based on the automatically displayed initial value and machining value.

Normally, the NC device recognizes the tool corresponding to the T code (the number indicating the tool mounting position of the turret in the case of a turret lathe), so that the motor to be monitored is automatically set for the type of the tool. Is convenient. Therefore, in such a case, the operator T
It suffices to input the code and set the damage value based on the monitored motor and the initial value and machining value displayed by the code. Since the example of FIG. 6 is a screen immediately after the test processing, the initial value and the processing value are equal. The initial value does not change in the state after machining some workpieces, and the machining value is changed to the maximum value of the load when machining the immediately preceding workpiece. Instead of registering the T code, it is of course possible to register the tool number and automatically convert the tool number and the T code by referring to the machining program.

[0029]

According to the present invention described above, it is extremely easy to set an automatic monitoring section for the machining load during machining of a workpiece, and the upper limit value (damage value) of the machining load can be set easily and without error. effective. In addition, since the graph display of the machining load on the monitor is updated and displayed each time the tool is changed, the operator can see the load fluctuations for each tool in more detail. There is an effect that the state can be monitored more easily and surely.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

2 is a machine tool (lathe) to be monitored by the device of FIG.
Schematic diagram of

FIG. 3 is an explanatory diagram showing a processing load graph display screen.

FIG. 4 is a flowchart of an interrupt program when reading a T code.

FIG. 5: Flow chart of graph display program

FIG. 6 is an explanatory diagram showing an example of a data input screen.

[Explanation of symbols]

 1 Spindle motor 2 Z-axis feed motor 3 X-axis feed motor 4 Milling motor 11 Motor 16 (A to C) Processing device 17 Comparator 19 OR circuit 20 to 24 Current detector 31 Graph display device 32 Memory 34 Input screen display means 35 Data input means

Claims (3)

[Claims] 1. A load detection device (21 to 24) for a motor (1 to 4) equipped on a machine tool, and a calculation processing device (16A, 16A,
16B, 16C), graph display means (31), and display monitor (1
In the machining load monitoring device for machine tools equipped with 1),
When a new tool selection is instructed from the machining program of the NC device that controls the machine tool, the arithmetic processing unit (16C)
The processing load monitoring device, wherein the screen display command is given to the graph display means (31). 2. A load detection device (21 to 24) for a motor (1 to 4) equipped in a machine tool and an arithmetic processing device (16A, 16A,
16B, 16C) and a comparator (17A, 17B) for comparing the detection value obtained by the arithmetic processing with the set upper limit value, and when it is detected that the detection value is larger than the upper limit value, NC In a machining load monitoring device for a machine tool which gives an overload detection signal to the device, a memory (32) for storing a monitoring section designation file composed of a plurality of records including a tool ID and an upper limit value of the load, and a machine tool control When a new tool selection is instructed from the machining program of the NC device, a record including the new tool ID is searched from the monitoring section designation file, and when a record to be searched exists, the record is searched for. A processing load monitoring device characterized in that an upper limit value of load is given to a comparator (17). 3. A memory (32) for storing the maximum value of the load detected during machining together with the tool ID of the tool used for machining.
, A data input device (35), and a monitor (1
1), an input screen display means (34) for displaying the record input screen of the monitoring section designation file, and an arithmetic processing unit (16C), and data is displayed when the data input screen is displayed on the monitor (34). When the tool ID and the motor ID are input from the input device (35), the arithmetic processing unit (16C) reads the maximum load detection value of the motor when the tool is used from the stored data in the memory (32). The processing load monitoring device according to claim 2, wherein the monitoring load is displayed on the monitor (11).