JPS6274553A - Method for detecting abnormality in machine tool - Google Patents

Abstract

PURPOSE:To improve accuracy in judging abnormality by obtaining and storing the rotating position of a cutting tool when an abnormal vibration is detected, and defining said tool as abnormal when abnormal vibrations are continuously detected for a certain number of rotations in the same rotating position. CONSTITUTION:In a cutting-tool abnormality detecting device 24, a threshold value for detecting abnormal vibration is previously operated from the average value of vibration signals which are inputted via an amplifier 22 in an operated circuit incorporated in the device 24, and the magnitude of a vibration signal is compared with the threshold value in an abnormality judging circuit. If the vibration signal is larger than the threshold value, the abnormality judging circuit outputs an abnormality signal while, at the same time, it stores an encoder value. And, when a milling machine 12 again outputted an abnormality signal with the same encoder value, the cutting tool in the rotating position is defined as abnormal and a warning signal is outputted from a warning device 26.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for detecting an abnormality in a cutting tool, and in particular, the present invention relates to a method for detecting an abnormality in a cutting tool of a milling machine. The present invention relates to an improvement in a method for detecting an abnormality in a cutting tool when cutting a fracture-resistant phase while avoiding the rotation of a cutting operator installed in the machine.

(Conventional technology 1) "An abnormality in the cutting tool of a milling machine naturally leads to an abnormality in the cutting surface of the fracture-resistant phase that is cut by it. Therefore, early detection of the abnormality by the cutting operator is important. This is important in maintaining the finish viscosity of a certain workpiece.

Furthermore, when milling a fracture-resistant phase using the milling machine, if one cutting tool is abnormal, for example, broken, the cutting amount that the cutting tool was originally supposed to cut will be reduced to the next cutting amount of the cutting tool. There will be 14 tools. In normal milling, the amount of cutting is often small, but in heavy cutting, for example, in edge milling equipment that cuts the side edges of steel plates, there is a large amount of cutting with a glue cutting tool for each sheet. In equipment where cutting tools are
However, since this is equivalent to assigning 6N of cutting for two cutting tools to the next cutting tool, it is easy to judge the excessive amount of cutting and suspect damage to the cutting worker. Therefore, damage to one cutter may cause damage to successive cutters in a chain, resulting in serious damage.

How to cover cutting tools to prevent such damage? %
1' detection method includes, for example, the Japanese Patent No. 8 Sho 57-16304.
There is a cutting tool damage detection method proposed in No. 2.

This is done by installing damage sensors on a large number of cutting tools.
By transmitting the No. 15 detected by the sensor from the transmitter installed in each sensor and receiving the enlightenment with one receiver, it is possible to create There is a detection method characterized by detecting abnormalities in tool vibration, temperature, cutting force, etc. during cutting.

(Problem to be solved by the invention 1 However, the above-mentioned Japanese Patent Application Laid-Open No. 57-163042
When abnormal vibration of a cutting tool is detected using the method proposed in
For example, there is a risk of detecting vibrations caused by variations in the quality of the material to be cut, increases or decreases in the amount of cutting due to human precision, or variations in the hardness of the material to be cut.

When vibrations caused by disturbances other than the tool as described above overlap with abnormal vibrations caused by the cutting tool, if an abnormality in cutting 11 rl is detected based on the severity of the detected vibration, it may be possible to detect abnormalities other than the abnormality in the cutting tool. Let's include the signal in Y.: Regular detection A5 and perform excessive detection. Therefore, the above-described detection method has a problem in that the abnormality in the cutting amount I cannot be accurately detected based on the abnormal vibration.

OBJECT OF THE INVENTION 1 The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to reliably distinguish between vibrations caused by abnormalities in cutting tools and vibrations caused by ponding, and to detect abnormalities caused by cutting workers. The purpose of the present invention is to provide a method for detecting abnormalities in cutting tools that can accurately detect abnormalities in cutting tools.

[Means for Solving the Problems] The present invention, as shown in FIG. and the rotational position, based on the average value of the detected vibrations, find a threshold value that serves as a reference for detecting abnormal vibrations of the cutting tool, and compare the found threshold value with the detected vibrations to detect abnormal vibrations. is detected, the rotational position of the cutting tool at the time when the abnormal vibration is detected is determined twice, and the abnormal vibration is detected a predetermined number of times in succession at the same @ rotation position, The above object has been achieved by detecting abnormalities in the cutting tool.

[Operation 1] Generally, a predetermined number of cutting tools are arranged on a rotary disk of a cutting machine, and as the rotary disk rotates, the material to be cut is sequentially cut. After cutting, the blade of the cutting tool performs lino cutting on the material to be cut again in the next rotation. At this time, each cutting worker's blade is used for cutting once in one rotation.

Now, if one of the cutting workers is abnormal, abnormal vibration will occur during the first month of cutting and every time the material to be cut is cut. This abnormal vibration occurs at a specific rotational position corresponding to the location of the cutting tool on the rotary disk. Therefore, by combining this rotational position and abnormal vibration and examining the reproducibility of whether abnormal vibration occurs continuously at the same rotational position, it is possible to detect an abnormality in the cutting tool.

The present invention is based on such knowledge and exhibits the following effects.

That is, when cutting a workpiece with a rotating cutting tool, the vibration of the cutting amount 1 and its rotational position are detected. Then, based on the average value of the detected vibrations, the cutting 1 [threshold value that serves as a reference for detecting abnormal vibrations of shellfish] is determined. Further, detecting abnormal vibration of the cutting tool by comparing the vibration with a threshold value,
When the abnormal vibration is detected, the cutting tool displacement indicated by IYj is determined and stored. At this time, an abnormality in the cutting tool is detected based on the fact that the abnormal vibration is detected a predetermined number of times in succession at the same rotational position. In this way, it is possible to reliably distinguish between vibrations that occur when the cutting tool is abnormal and vibrations that occur due to other causes, and to detect abnormalities in the cutting tool with good accuracy.

[Example] Hereinafter, a detailed description will be given of an actual iJ color example of an abnormality detection device in which the cutting tool abnormality detection method according to the present invention is adopted.

As shown in FIG. 2, this embodiment detects an abnormality in a cutting tool of a milling machine 12 that cuts a material 10 to be cut.

The drive device that drives the milling machine 12 includes a J drive motor 14 that generates a driving force to rotate the milling machine 12, and a speed changer that changes the driving force of the drive motor 14 to the milling machine 12. It is equipped with 1G.

Further, the +if abnormality detection device includes a drive motor 14 for outputting rotational position signals corresponding to the positions of the blades 13 of a large number of cutting tools provided in the milling cutting machine 12 as encoder values. The attached rotary encoder 18, the vibration detector 20 that detects the vibration of the milling cutting machine 12, the amplifier 22 that amplifies the signal of the vibration detector 20, and the milling cutter that is input via the shadow amplifier 22. 1, 7J cutting tool abnormality detection device 24 that detects abnormality of the cutting tool based on the vibration signal of the cutting machine 12;
An alarm device 26 is provided which issues an alarm when an abnormality signal is output from the cutting tool abnormality detection device 24.

J3, the cutting tool abnormality detection device 24 has a
+ Threshold that serves as a standard for detecting abnormalities in signal size (
A calculation circuit that calculates the signal B1 from the average value of the magnitude of the shaking J signal outputted from the amplifier 22, and an abnormality determination circuit that compares the drive and the signal threshold are incorporated.

The example for Vr will be explained below.

When the workpiece 10 is being cut by the milling machine 12, the vibration of the milling machine 12 is detected by the vibration detector 20, and sent via the amplifier 22 as a vibration signal g to the cutting tool abnormality detection device 24. is input. .

At this time, the cutting tool status detection device 24 continuously uses the encoder value output from the rotary encoder 18 as rotational position No. 15 having a rotational phase corresponding to the position of the blade 13 of the cutting tool I. Take in. At the same time, the cutting shell abnormality detection device 24 is incorporated therein, and the threshold value for detecting abnormal imaging in the circuit is determined by the average of the vibration signals inputted via the amplifier 22. The value is calculated in advance, and then an abnormality determination circuit compares the magnitude of the vibration signal with a threshold value. Here, if the vibration signal at a certain time becomes larger than the threshold value, the abnormality determination circuit determines abnormal drive at that moment, outputs an abnormal signal, and stores the encoder value at this time. Then, in the next rotation of this milling cutting machine 12, if an abnormal signal is output again with the same 1-d value,
This means that the abnormal signal of the cutting tool has been generated twice in succession at the same rotational position. In this way, when an abnormality (No. 5) occurs consecutively at the same rotational position a preset number of times (twice in the example), the cutting tool at that rotational position is considered to be abnormal and a six-day report is issued. An alarm (issue a) is output from the heavy duty 26.

When an abnormal signal is detected as described above, abnormality 5g, which normally occurs at an arbitrary position and is caused by the dimensions, hardness, etc. of the covered workpiece 1o, corresponds to the rotational position of the milling cutting machine 12.
Therefore, the probability that the alarm signal from the abnormal station is output from the alarm device 26 can be reduced to -4. Therefore, it is possible to extract only the abnormal signal corresponding to the position of the cutting tool on the corrugated milling cutting machine 12 due to the abnormality of the cutting tool, based on its reproducibility.

On the other hand, the number of times the reproducibility of the above-mentioned false accusation is diagnosed is set to 2, for example.
If the number of repeatability tests is repeated, there is a high possibility that the abnormal signal will be detected by chance, but as the number of times this reproducibility diagnosis is increased, the possibility becomes lower. I] is output, the probability that the cutting tool is abnormal increases.

Here, an example will be described in which an abnormality in a cutting tool installed in an actual milling machine is detected. In this case, the milling machine has a cutter diameter of 1200 mm, and
It is equipped with 84 cutting tools arranged in an array. In the past, a piezoelectric vibration detection plate was used as the vibration detector 20.

The vibration number detected by the vibration detector 20 is 913
A waveform 50 as shown in the figure (Δ) was created. This vibration signal 50 was averaged, and twice the number of vessels was set as 12 values. The value of the threshold value (Bi1) at this time was in the state shown by the waveform 52 in the same figure. At this time, since the value where the vibration signal 50 exceeded the threshold value 52 was considered to be abnormal vibration, the abnormal vibration An abnormality signal 54 due to
) (the numbers in the figure are the encoder values)
From (B) and (C) in the same figure, it can be seen that the abnormal signals a and C are generated when the 1-encoder value (30) is the same. Here, in this example, since the number of reproductions of abnormality No. 15 is set to 2 in advance, the abnormality signal a,
cTs:J: Detects abnormality 1i in the cutting tool, and as shown in Fig. 3 (D
) was output as an alarm signal 5B.

It should be noted that the abnormal signal shown in FIG. 3(B) is not reproduced with the same encode value (45), so the alarm 1'' is issued.

5 was not output.

In the above embodiments, a milling machine was used as an example of a cutting machine, but the cutting machine is not limited to a milling machine and may be any other cutting machine. .

[Efficacy of invention! ul Abnormality As explained above, according to the present invention, a large number of abnormal vibrations detected from a cutting tool can be removed from the cutting machine ξ! Since the reproducibility is checked in association with each of the above, abnormal vibrations other than abnormal vibrations of the cutting tool can be excluded, and the five abnormalities of the cutting worker can be detected with high reliability.

Therefore, abnormalities in cutting tools during continuous cutting can be detected early,
By taking measures such as stopping the equipment, it is possible to prevent damage to other cutting tools as a chain reaction, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the gist of the present invention, FIG. 2 is a perspective view showing the configuration of an embodiment of an abnormality detection device in which the cutting tool abnormality detection method according to the present invention is adopted, and FIG. )(B)
(C) and (D) are diagrams showing an example of the relationship among the vibration J signal, the abnormal vibration signal, the encoder value, and the alarm signal detected in the embodiment. 10... Fractured cutting material, 12... Milling cutting machine, 13... Cutting tool blade, 14... Drive motor, 18... Rotary encoder, 20... Circulation ω" detector, 24...Cutting tool abnormality detection device, 26...Alarm device, 5o...Vibration signal, 52...Threshold (direct), 54...Abnormal signal, 56...Encoder value, 58... Alarm signal. Agent Takaya 1 Tsutomu Matsuyama Figure 1 Figure 3

Claims (1)

[Claims] (1) When rotating a cutting tool equipped on a cutting machine to cut a material to be cut, detect the vibration and rotational position of the cutting tool, and calculate the vibration of the cutting tool based on the average value of the detected vibrations. A threshold value serving as a reference for detecting abnormal vibration is determined, abnormal vibration is detected by comparing the determined threshold value with the detected vibration, and the rotational position of the cutting tool when the abnormal vibration is detected is determined and stored. A method for detecting an abnormality in a cutting tool, characterized in that an abnormality in the cutting tool is detected based on the abnormal vibration being continuously detected a predetermined number of times at the same rotational position.