JPH0751994A - Numerical control device for machine tool - Google Patents

Abstract

PURPOSE:To make accurate measurement of a machining time at each machining process even when a work is machined at a plurality of processes. CONSTITUTION:In a first processing part 1, an NC program is called from an NC program memory part by a first processing device 3 based on machining information inputted from an input part 4 and a work is machined by executing the NC program. In a second processing part, a machining time at each process is measured by given symbol and numeral described at the NC program by a second processing device 6 based on an input signal from the first processing part 1 simultaneously with execution of the NC program by a process time counting part 9. A machining time measured by a display means 7 is displayed together with each machining process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control device for machine tools.

[0002]

2. Description of the Related Art Conventionally, in a machine tool equipped with a numerical control device, a method of using a timer of a sequencer and a method of timing processing in an NC program have been adopted as methods of measuring the machining time of a work.

[0003]

However, the former method cannot accurately measure the time by the timer of the sequencer when there are many machining steps of the work and the required time for each machining step is short (0.05 to 10 seconds). There was a problem.
On the other hand, in the latter method, for example, as shown in FIG. 5, a plurality of timings are measured between one processing step (n) (step S _n ) and the next processing step (n + 1) (step S _{n + 6} ). Since the processes (steps S _{n + 1} , S _{n + 3} , S _{n + 5} ) are included, there is a problem that the time processing of these processes takes time and the entire processing time becomes long.

[0004]

The present invention has been made in view of the above problems, and the first aspect of the present invention is as follows.
In a numerical control device of a machine tool for machining a workpiece into a predetermined shape by executing an NC program in the NC processing unit, the numerical control device is provided in a second processing unit different from the first NC processing unit, Machining time measuring means for measuring the machining time for each step using predetermined symbols and numbers described in the NC program, and a display for displaying the machining time measured by the machining time measuring means together with each machining step And means are provided.

According to the second aspect of the present invention, a storage means for storing the processing time measured by the processing time measuring means is provided, and the display on the display means indicates the current processing for each processing step. The machining time of the workpiece and the machining time of the previously machined workpiece stored in the storage means are performed together.

According to a third aspect of the present invention, machining time comparing means for comparing the machining time of the workpiece currently being machined with the machining time of the workpiece machined immediately before, in each of the machining steps. A notifying unit for notifying an abnormality of the tool based on the comparison result of the machining time comparing unit is provided.

According to a fourth aspect of the present invention, there is provided tool change informing means for accumulating the machining time measured by the machining time measuring means for each machining step and notifying tool exchange based on the accumulated time. It is provided.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic circuit configuration of a numerical control device for a machine tool according to the present invention. This numerical controller comprises a first processing section 1 and a second processing section 2. First processing unit 1
Is the first processing device 3, the input unit 4, the NC program storage unit 5
Is equipped with. The second processing unit 2 includes a second processing device 6, a display unit 7, a data storage unit 8, a process time counting unit 9, and an abnormality notification unit 1.
It has 0.

The processing contents of the numerical controller having the above configuration will be briefly described. In the first processing unit 1, the processing information is input to the first processing device 3 from the input unit 4. The first processing device 3 calls the NC program from the NC program storage unit 5 and executes it based on the processing information to process the work into a predetermined shape. The NC program is composed of a plurality of blocks. Each block corresponds to one machining process of the work and is given a specific N number. In the grinding process shown in this embodiment, the N number in the 9000 range (9nn
n: 9001 to 9999, where 9999 indicates the end of processing. ) Is attached to each block. Specifically, 9004 is rough processing and 9008 is finishing processing. The contents of the NC program can be changed based on the input from the input unit 4.

In the second processing unit 2, the NC
When the N number of the program is input to the second processing device 6,
It is determined whether or not this N number is in the 9000 range. 9
If it is an N number in the 000's, the process time counting unit 9 counts the processing time of the processing process corresponding to the N number, and the processing time is stored in the data storage unit 8. In addition, the processing time is sequentially displayed together with the names of the processing steps or the symbols corresponding thereto in the display unit 7.
Is displayed on the CRT (not shown). When a plurality of workpieces are machined by repeatedly executing the same NC program, the display unit 7 simultaneously displays the machining time of each process counted during the previous machining of the workpiece.

Next, taking the case of grinding as an example, FIG.
The processing contents of the numerical controller will be described in more detail with reference to FIGS. When the machining information such as the machining shape, machining dimension, tool to be used, machining condition, etc. of the work is input from the input unit 4, the first processing unit 1 calls the NC program from the NC program storage unit 5. Then, this NC program is executed according to the flowchart of FIG. 2 based on the processing information. That is, as shown in steps S1 to S12,
The steps of indexing, rough semi-express, black leather, rough machining, rough spark-out, dress, finishing semi-express, finishing, finishing spark-out, overfeed, table retraction, and idling are sequentially executed.

On the other hand, the second processing section 2 executes the processing of counting the processing time in parallel with the execution of the processing step in the first processing section 1 according to the flow chart shown in FIG. That is, in the second processing device 6, it is determined whether or not the N number of the NC program input from the first processing unit 1 in step S21 is the N number in the 9000 range representing the processing of the machining process, and the N number is in the 9000 range. If not, it waits without performing the processing described below. If the N number is in the 9000 range, it is determined in step S22 whether the N number is "9999". The N number "9999" means the end of the machining process, and is the end of the NC program, that is, the step S1.
It is provided after 2. Therefore, the N number is "99.
If it is "99", the following processing is not executed, and the process proceeds to step S28. If it is an N number in the 9000 range other than "9999", the process proceeds to step S23.

In the process time counting section 9, after clearing the timer counter in step S23, the timer counter is started in step S24 to measure the time required for each machining process. Next, in step S25, it is determined whether or not a different N number in the 9000 range is newly input from the first processing unit 1. And a new N in the 9000 range
If no number is input or the same N number in the 9000 range is input, the counting process of the process is continued, and if a new N number in the 9000 range is input, the counter is stopped in step S26 to perform the counting process. To finish.

Then, in step S27, as shown in FIG. 4, the measured machining time is displayed on the display unit 7 together with the name or symbol of the corresponding machining process, and the machining time is stored in the data storage unit 8. Remember. Further, the display unit 7 indicates not only the machining time of each machining process for the workpiece currently being machined but also each machining time of all the machining processes for the workpiece machined before is called from the data storage unit 8 at the same time. Is displayed. It is preferable that the machining time of the immediately preceding work be called from the data storage unit 8 before the machining of a new work is started and displayed on the display unit together with the machining process.

By repeating the steps S21 to S27, the processing time of each processing step which is sequentially executed is counted. When all the machining steps are completed, the N number becomes "9999" as described above, so the machining time counting process is also completed by the determination in step S22.

As described above, in the above embodiment, the NC program is executed by the first processing unit 1, and in parallel with this process, the second processing unit 2 measures and displays the processing time for each processing step. I am trying to do. Therefore,
Even though the time required for each of the processing steps is short, accurate measurement can be performed. As a result, for example, when the tool used is a grinding wheel, the timing for dressing the tool can be easily set based on the measured processing time.

Further, since the machining time of the work currently being machined and the work machined immediately before is displayed, the operator can recognize the change in the machining time at a glance, and an abnormality occurs in the tool. When it is done (whether or not a dress is necessary for the grinding wheel), the judgment becomes easy.

In the above embodiment, the machining time of the workpiece currently being machined and the machining time of the immediately preceding workpiece are displayed together with the machining process, and the operator can judge the abnormality of the tool by looking at the machining time. , The second processing unit 2 compares the two processing times, and when the difference becomes larger than a predetermined threshold value, the operator is notified by the abnormality notification unit 10 such as a buzzer or a lamp or the screen display on the CRT. You may do it. However, in this case, it is preferable to control so that the machining is automatically stopped or the tool is maintained when the second processing unit 2 detects an abnormality in the tool.

In the above embodiment, the tool abnormality is detected by comparing the machining times. However, the second processing section 2 is provided with a cumulative data storage section (not shown), and this storage section is provided. It is also possible to store the cumulative machining time for each machining step and display it on the display unit 7. Further, the cumulative processing of the cumulative machining time, that is, the processing of adding the machining time for the workpiece currently being machined to the already stored cumulative machining time may be performed at the time when one machining step is completed, It may be performed after the machining of the workpiece currently being machined is completed. Then, when the cumulative machining time exceeds the durability time of the tool used for each machining, it is convenient to notify the replacement of the tool by the abnormality notifying unit 10 so as to prompt the replacement and maintenance of the tool. Further, other symbols may be used for the symbol N for measuring the machining time used in the above-mentioned embodiment, and the numbers in the 9000 range may be the numbers in other ranges.

[0020]

As is apparent from the above description, according to the invention described in claim 1, the execution of the NC program and the measurement of the machining time are performed by separate processing units, and the machining time is reduced to the NC. Since the measurement is performed using the predetermined symbols and numbers described in the program, it is possible to measure the processing time for each processing step, which has been difficult to measure in the past. Further, since the measurement result is displayed, it is possible to efficiently take out the material and maintain the tool.

According to the second aspect of the present invention, the machining time currently being machined is displayed together with the machining time immediately before, so that both machining times can be compared and a tool abnormality can be reliably detected. can do.

According to the third aspect of the present invention, the machining times are compared by the machining time comparing means, and if the tool is abnormal, the informing means informs the operator. There is no need to keep track of changes over time.

According to the fourth aspect of the present invention, the tool usage time and the like are taken into consideration based on the result of accumulating the machining time for each machining step. Therefore, maintenance is performed before the tool reaches its durable life. Can be applied.

[Brief description of drawings]

FIG. 1 is a block diagram showing a numerical control device according to the present embodiment.

FIG. 2 is a flowchart showing a method for processing a work piece.

FIG. 3 is a flowchart showing a method for measuring processing time.

FIG. 4 is a table showing processing steps and processing times displayed on the display unit of FIG. 1.

FIG. 5 is a flowchart showing a method for machining a workpiece and a method for measuring machining time according to a conventional example.

[Explanation of symbols]

1 ... 1st process part (processing control means), 2 ... 2nd process part, 3
... first processing device, 5 ... NC program storage part, 6 ... second
Processing device, 7 ... Display unit (display unit), 8 ... Data storage unit (storage unit), 9 ... Process time counting unit (processing time measuring unit), 10 ... Abnormality notifying unit (notifying unit).

Claims (4)

[Claims] 1. A numerical control device for a machine tool for machining a workpiece into a predetermined shape through a plurality of steps by executing an NC program in the first NC processing unit, and a second processing different from the first NC processing unit. And a machining time measuring means for measuring machining time for each step using predetermined symbols and numbers described in the NC program, and machining time measured by the machining time measuring means. A numerical control device for a machine tool, comprising: a display means for displaying together with a machining process. 2. A storage means for storing the processing time measured by the processing time measuring means is provided, and the display means displays, for each processing step, a processing time of a workpiece currently being processed and the storage means. The numerical control device for a machine tool according to claim 1, wherein the machining time of the previously machined workpiece stored in is also displayed. 3. A machining time comparing means for comparing a machining time of a workpiece currently being machined with a machining time of a workpiece machined one before in each machining step, and the machining time comparing means. The numerical control device for a machine tool according to claim 2, further comprising an informing unit for informing an abnormality of the tool based on the comparison result. 4. A tool change notifying means for accumulating the machining time measured by the machining time measuring means for each machining step and notifying tool change based on the accumulated time. The numerical control device for a machine tool according to claim 1.