JPH05169355A - Tool abnormality detection device - Google Patents

Abstract

PURPOSE:To provide a tool malfunction detector that makes a tool detectable irrespective of size in the degree of its malfunction and applicable even to precision machining. CONSTITUTION:This detector is provided with a spatial frequency analytical means 6 which analyzes an image being obtained by photographing the machined surface of a work 4 by means of a cutting tool 3 with a TV camera 2, in direction of a turning shaft of the work 4, and detects something wrong with the cutting tool 3 on the basis of a distribution of spatial frequency constituent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool abnormality detecting device.

[0002]

2. Description of the Related Art If a tool is chipped or worn during cutting, the machining accuracy and reliability of the work will be deteriorated. As a countermeasure, it is important to constantly manage the soundness of the tool. However, in the conventional technology, since the worker visually judges the quality of the cutting tool, there are many variations in the judgment due to individual differences among workers, and the judgment of the tool abnormality detection is non-quantitative. . As a means for automatically detecting a tool abnormality during machining of a workpiece by a machine tool, for example, in lathe machining, the workpiece and the current value of the motor that rotates the workpiece are monitored, and when a tool abnormality occurs, the motor load is detected. Since the motor current fluctuates and changes, a means for detecting this is known.

[0003]

However, in the case where the degree of tool abnormality is extremely large with such means,
Although it can be detected, it cannot be detected when the degree of abnormality is small. Therefore, the current state of the art is that motor current detection is not applied to precision machining such as finishing machining.

The present invention has been proposed in view of the above circumstances, and it is an object of the present invention to provide a tool abnormality detecting device which can detect a tool abnormality irrespective of the magnitude thereof and can be applied to precision machining. To aim.

[0005]

To this end, the present invention has means for spatially frequency-dividing an image obtained by photographing a surface of a workpiece to be cut by a cutting tool with a TV camera in the rotational axis direction of the workpiece, An abnormality of the cutting tool is detected based on the distribution of the spatial frequency component.

[0006]

[Function] The cutting surface of the work being cut is subject to change in state due to the feed of the cutting tool, pitch, speed torque, and shape of the cutting edge, etc. It is converted to the distribution of the spatial frequency component in the lateral direction and compared with the distribution of the normal spatial frequency component to detect an abnormality at the tool processing end.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view and an overall system diagram thereof, and FIG. 2 is a diagram showing the lightness and darkness of a TV camera image when a cutting tool is normal or abnormal. 3 is an original image diagram by the frequency analysis device when the cutting tool is normal and abnormal in FIG. 1, and FIG. 4 is a flowchart showing an operating procedure of the device of FIG.

First, in FIG. 1, the irradiation line 5 constantly output from the light source 1 irradiates the processing member 4 during cutting, and the surface of the processing member 4 irradiated by the irradiation light 5 is exposed to the TV camera 2.
The image is captured by and the frequency analysis device 6 decomposes it into spatial frequency components in the lateral direction.

Here, the spatial frequency component is a value indicating how many times the lightness / darkness has changed per unit length, and assuming that the tool is normal, for example, as shown in FIG. If the brightness and darkness change, the spatial frequency is 1 [1 /
mm]. This is because the cutting trace is constant based on the constant cutting depth, cutting position, and tool cutting shape of the tool, and the spatial frequency component is also constant.

On the other hand, when an abnormality occurs in the cutting tool, as shown in FIG. 1B, the cutting marks, that is, the cutting marks, are cut based on changes in the cutting depth, the cutting position, the cutting edge of the tool, etc. The spatial frequency component fluctuates, and in the case of the same figure, the spatial frequency component becomes 1.75 [1 / mm].

FIG. 3 shows an example of the spatial frequency component distribution obtained when the cutting tool 3 is decomposed using the apparatus as described above when the cutting tool 3 is normal and when the cutting tool 3 is abnormal. That is, when the cutting tool 3 is in a normal state, as shown in (A) of the same figure, the original image taken by the TV camera 2 has cutting traces evenly arranged, and the spatial frequency component distribution has a low frequency. And two peaks are seen at high frequency. However, if an abnormality occurs in the cutting tool 3, as shown in FIG.
The original image picked up by the V camera 2 has non-uniform cutting traces, and the spatial frequency component distribution differs from the normal state due to the different peak numbers.

Based on such a relationship, the spatial frequency component distribution when the cutting tool 3 is normal is stored in the storage device 7 in advance and compared with the spatial frequency component distribution obtained during cutting. The processing is continuously performed by the device 8 to detect an abnormality of the cutting tool 3, and the processing result is displayed on the screen using the display device 9.

[0013]

According to such an apparatus, it is not necessary for an operator to visually check the state of the cutting tool at all times, labor can be saved, and abnormalities of the cutting tool can be quantitatively evaluated.
The reliability and accuracy of the workpiece are improved.

In short, according to the present invention, there is provided means for spatially frequency-dividing an image obtained by photographing the cutting surface of the work by the cutting tool with the TV camera in the rotational axis direction of the work, and the distribution of the spatial frequency components. By detecting an abnormality of the cutting tool based on the above, it is possible to detect this regardless of the magnitude of the tool abnormality, and a tool abnormality detection device applicable to precision machining is obtained, so the present invention is extremely useful in industry. It is something.

[Brief description of drawings]

FIG. 1 is a perspective view and an overall system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the brightness of a TV camera image when the cutting tool is normal and when it is abnormal in FIG.

FIG. 3 is an original image diagram by the frequency analysis device when the cutting tool is normal and abnormal in FIG.

FIG. 4 is a flowchart showing an operating procedure of the apparatus of FIG.

[Explanation of symbols]

 1 Light Source 2 TV Camera 3 Cutting Tool 4 Processing Member 5 Irradiation Light 6 Frequency Analysis Device 7 Storage Device 8 Comparison Device 9 Display Device

Claims (1)

[Claims] 1. A cutting tool having means for spatially frequency-dividing an image obtained by photographing a cutting surface of a work by a TV camera with a TV camera in the rotational axis direction of the work, and based on the distribution of the spatial frequency component. A tool abnormality detection device, which is characterized by detecting an abnormality in the tool.