JPS6124146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool abnormality monitoring method, and more particularly to a tool abnormality monitoring method in which tool abnormality monitoring data is created during trial cutting and tool abnormality determination is made by referring to the data during recutting.

In general, in machine tools, when a tool abnormality such as tool breakage or wear occurs, a workpiece becomes defective, so it is necessary to promptly detect the abnormal tool. In order to monitor the occurrence of this tool abnormality, the current value of the spindle motor of the machine tool is compared with tool abnormality monitoring data, and a tool abnormality is determined. This tool abnormality monitoring data is created based on the current change data of the spindle motor obtained during trial cutting.
It is necessary to introduce monitoring information such as diameter, number of blades, etc.), abnormality judgment criteria (tolerable values), etc. Here, the criterion for abnormality determination can be changed to various values depending on the characteristics of the tool, etc., and is set to, for example, +20% of the above-mentioned current data at the time of trial cutting.

FIG. 1 shows a tool abnormality monitoring device that performs the tool abnormality monitoring described above. As shown in FIG. 1, the numerical control device 1 not only gives control commands to the machine tool 4, but also provides NC command information (for example, what kind of tool is currently used for machining) to the tool abnormality monitoring device 2, which is necessary for monitoring tool abnormalities. provide information about the current situation). Further, the tool abnormality monitoring device 2 receives monitoring information such as abnormality determination criteria and tool characteristics through the input device 3. Furthermore, when trial cutting is performed, the main motor current data from the servo unit of the numerical control device 1 is input to the tool abnormality monitoring device 2, and the current data at the time of trial cutting and the above-mentioned monitoring information are processed as data in the monitoring device 2. Processed and tool abnormality monitoring data is created. Fig. 2 shows a fluctuation curve I _R of the spindle motor current during trial cutting (here, the convex part of the curve shows the cutting process, and the concave part shows the idle cutting time), and the current variation curve based on this current variation. A tolerance curve _ID is shown. Usually, the tool abnormality monitoring data is created as a function of time so as to correspond to the tolerance curve _ID .

FIG. 3 shows a block circuit of a tool abnormality monitoring device conventionally used to perform the above-mentioned tool abnormality monitoring. In the tool abnormality simplification device shown in FIG. 3, the above-mentioned monitoring information is inputted in advance to the tool abnormality judgment standard and tool characteristic output circuit 51 by a manual input device or recorded on an NC tape, etc. , current value output circuit 52 during trial cutting
Only when trial cutting is performed, the main spindle electric current of the machine tool is appropriately sampled and the gate circuit 53 is
supply to. The gate circuit 53 is connected to the outputs of the abnormality determination criterion and tool characteristic output circuit 51 and the trial cutting current value output circuit 52, and the outputs of both are supplied to the processing device 54 only during trial cutting. In the processing device 54, tool abnormality monitoring data is created based on the above two signals,
This data is provided as an output of processing unit 54 to monitoring data storage 55 . In the monitoring data storage device 55, the tool abnormality monitoring data described above is stored. The output of the monitoring data storage device 55 is
The signal is supplied to the tool abnormality determination circuit 57. The tool abnormality determination circuit 57 is also supplied with the output of the NC information output circuit 56, that is, the current data of the spindle motor during re-cutting. The tool abnormality determination circuit 57 determines whether or not there is a tool abnormality based on the output signals from both the storage device 55 and the output circuit 56. If a tool abnormality exists, that is, the output data from the output circuit 56 is stored in the storage device 55. An alarm signal is generated if the monitoring data (so-called threshold) from the sensor is exceeded.

In the tool abnormality monitoring device shown in Fig. 3, the tool abnormality judgment criteria and monitoring information such as tool characteristics are set in advance according to empirical rules before starting trial cutting, or are set independently of trial cutting. Therefore, it is not possible to variably introduce monitoring information while performing trial cutting, that is, depending on the cutting condition at the time of trial cutting, and it is not possible to introduce complex information according to conditions such as tool characteristics. The problem is that it needs to be configured.

In view of the problems of the conventional method, the main purpose of the present invention is to variably introduce monitoring information according to the cutting conditions at the time of trial cutting while performing trial cutting. (Usually, the cutting state is judged by vibrations and cutting sounds during cutting), monitoring information can be variably input manually, i.e. via the keyboard, thereby detecting tool abnormalities. It is an object of the present invention to provide a tool abnormality monitoring method that allows monitoring data to be created simply and with flexibility. This allows the above-mentioned monitoring data, which serves as a threshold for determining tool abnormality, to be arbitrarily set according to the test cutting conditions that are normally performed each time the workpiece is replaced (in this case, the tool is also generally replaced). It can be increased or decreased. That is, in the present invention, in the tool abnormality monitoring method, tool abnormality monitoring data is created during trial cutting, and tool abnormality determination is performed by referring to the data during recutting. Monitoring information such as judgment criteria is variably introduced according to the cutting condition during trial cutting, and the current change data of the spindle motor during trial cutting is automatically changed and corrected, and the modified cutting current is A tool abnormality monitoring method is provided, which is characterized in that change data is stored in a storage device as tool abnormality monitoring data, and tool abnormality determination at the time of re-cutting is performed based on the stored tool abnormality monitoring data.

FIG. 4 shows a tool abnormality monitoring device used in a tool abnormality monitoring method as an embodiment of the present invention. In the tool abnormality monitoring device shown in Fig. 4,
An abnormality determination criterion and tool characteristic input device 61 is connected to the gate circuit 63 , and the output of the trial cutting current value output circuit 62 is also connected to the gate circuit 63 . In the gate circuit 63, even when current value input is supplied during trial cutting, monitoring information such as abnormality determination criteria and tool characteristics can be variably introduced according to the situation at the time of trial cutting. Two inputs are provided to processing unit 64. The processing device 64 creates tool abnormality monitoring data based on the two input signals and supplies this tool abnormality monitoring data to the monitoring data storage device 65. The tool abnormality monitoring data is stored in the monitoring data storage device 65 , and the stored tool abnormality monitoring data is supplied to the tool abnormality determination circuit 67 . The tool abnormality determination circuit 67 also includes an NC information output circuit 66.
, that is, the current data of the main shaft motor at the time of re-cutting. Tool abnormality determination circuit 67
The presence or absence of a tool abnormality is determined based on the above two inputs, and if a tool abnormality exists, that is, the output data of the output circuit 66 exceeds the monitoring data (so-called threshold value) from the storage device 65. If so, an alarm signal is generated.

In the tool abnormality monitoring device shown in FIG. 4, the abnormality determination criteria and tool characteristic input device 61 are used to automatically change and correct the current change data of the spindle motor. Monitoring information can be introduced variably. Further, it is also possible to set a plurality of standard data regarding the monitoring information in advance and select the most suitable one from among the plurality of data during trial cutting.

According to the present invention, it is possible to manually input monitoring information variably during trial cutting according to the situation at the time of the trial cutting, thereby making it possible to create tool abnormality monitoring data concisely and with flexibility. A tool abnormality monitoring method is provided, which allows tool abnormalities to be accurately monitored based on the current cutting situation.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a device that generally monitors tool abnormalities during cutting with a machine tool, and Figure 2 shows changes in the current of the spindle motor during trial cutting and the current of the spindle motor in the device shown in Figure 1. A waveform diagram showing permissible values of change, FIG. 3 is a system diagram for explaining tool abnormality monitoring operation in a conventional tool abnormality monitoring device, and FIG. 4 is a tool abnormality monitoring as an embodiment of the present invention. FIG. 2 is a system diagram for explaining a tool abnormality monitoring operation in a tool abnormality monitoring device used in the method. Explanation of the numbers, 1: Numerical control device, 2: Abnormality monitoring device, 3: Input device, 4: Machine tool, 51: Abnormality judgment criteria/tool characteristics output circuit, 52: Current value output circuit during trial cutting, 53: Gate circuit, 54: Processing device, 55: Monitoring data storage device, 56: NC information output circuit, 57: Tool abnormality determination circuit, 61: Abnormality determination criterion/tool characteristic input device, 62: Current value output circuit during trial cutting, 63: Gate circuit, 64: Processing device, 65: Monitoring data storage device, 66: NC information output circuit, 67: Tool abnormality determination circuit.

Claims (1)

[Scope of Claims] 1. A tool abnormality monitoring method in which tool abnormality monitoring data is created during trial cutting and tool abnormality determination is performed by referring to the data during recutting, comprising: Monitoring information such as standards may be introduced depending on the cutting condition at the time of trial cutting, and the cutting current change data of the spindle motor at the time of trial cutting is automatically changed and corrected, and the modified cutting current is A tool abnormality monitoring method characterized by storing change data in a storage device as tool abnormality monitoring data, and determining a tool abnormality at the time of re-cutting based on the stored tool abnormality monitoring data.