KR101934705B1 - A lifetime diagnosis system for a spindle of multi-axis machine and a lifetime diagnosis method of the same - Google Patents

Abstract

The present invention relates to a lifetime diagnosis method for a spindle of a multiaxial machine, which comprises: a step of collecting data about operation characteristic factors of the spindle; a step of deriving a root mean square (RMS) value among data values about the operation characteristic factors and classifying data of the RMS value into each stage; a step of multiplying a weight value of each stage to each RMS value classified into each stage; and a step of summing the weight value of each stage and each RMS value classified into each stage to calculate a lifetime of the spindle. According to the present invention, the data of the RMS value is classified into each stage in consideration of characteristics that an effect affecting the lifetime of the spindle is changed in accordance with displacement of vibration generated from the spindle, and the weight value of each stage is multiplied to each RMS value classified into each stage, such that a displacement factor of the vibration generated from the spindle is applied to the lifetime of the spindle, thereby correctly calculating the lifetime of the spindle.

Description

TECHNICAL FIELD [0001] The present invention relates to a spindle lifetime diagnosis system and a life span diagnosis method for a spindle of a multi-

The present invention relates to a spindle lifetime diagnosis system and a life span diagnosis method for a spindle of a multi-axis processing machine, and more particularly, to a spindle life span diagnosis system and a life span diagnosis method of a multi-axis processing machine capable of diagnosing the spindle life in advance.

In general, a multi-axis processing machine means a mechanical device including two or more drive shafts, such as a multi-axis machine tool, a multi-axis joint robot, and a CMM.

Such a multi-axis processing machine generally includes at least one linear axis and at least one rotation axis. A typical example is a 5-axis machine tool, that is, a 5-axis machining machine. Usually, a 5-axis machine tool is composed of three linear axes and two rotation axes to perform processing of complex curved surfaces and shapes.

That is, the five-axis machining apparatus has five degrees of freedom in which three rotary feed axes are added to three linear feed axes.

In particular, the two degrees of freedom increased by two feed axes freely implement the posture of the tool, making it possible to easily process complex shapes or free-form surfaces such as reduction of cusp, removal of Un-cut, and over- .

On the other hand, when an abnormality occurs in such a multiaxial machining apparatus, it is very important to diagnose the abnormality of the multiaxial machining apparatus because it can cause enormous economic loss or injury to persons.

Especially, in the case of a spindle in which a tool is fastened in a multi-axis processing machine, a problem may arise when an abnormality occurs, and this abnormality may occur excessively when the spindle is continuously used even though the spindle has reached the end of its service life.

Therefore, it is necessary to diagnose the spindle life beforehand and to periodically replace or repair the spindle. However, until now, there has been no method for diagnosing the spindle life in advance.

On the other hand, various abnormal phenomena that may occur in various kinds of multi-axis processing machines have different characteristics depending on the use, specification, size, etc. of multi-axis processing machines, but they have common cause and characteristics due to the structural characteristic of multi-axis processing machine.

A vibration signal is often used to diagnose some common causes. The vibration signal is advantageous in that it is less influenced by surrounding environment than other data such as electrical characteristics, rotation direction, and temperature, which are considered for the diagnosis of abnormality, and can be commonly applied to multi-axis processing machines having a similar structure.

Theoretically, a multi-axis processing machine rotating at the same cycle can obtain an average vibration spectrum in the frequency domain, and it is possible to diagnose the operating state of the multi-axis processing machine by the pattern of the vibration spectrum.

Therefore, in the present invention, the life span of the spindle is to be diagnosed prior to diagnosis through the above-described vibration characteristics.

Japanese Laid-Open Patent Publication No. 1993-301149

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spindle life diagnosis system and a life span diagnosis method of a multi-axis processing machine capable of diagnosing the service life of a spindle in advance.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to solve the above-mentioned problems, the present invention provides a measuring apparatus comprising: a measuring instrument provided in a predetermined region of a spindle; A signal processing module for performing signal processing of measurement data output from the measuring instrument; A signal analysis module for providing schedule information based on measurement data; And a statistical processing module for processing the data transmitted from the signal processing module and performing statistical processing. The present invention also provides a spindle life diagnosis system for a multi-axis machine.

The statistical data provided by the statistical processing module may include at least one of standard deviation, kurtosis, skewness, and square root mean square (RMS) of the average data of the vibration displacement with respect to the acceleration data And a spindle lifetime diagnosis system for a spindle of a multi-axis processing machine.

Further, the present invention provides a system for measuring the life span of a spindle of a multi-axis processing machine including an acceleration sensor and a data logger.

The present invention also relates to a method of operating a spindle, comprising: collecting data on operating characteristic parameters of the spindle; Deriving an RMS value of data values for the operation characteristic factors, and classifying the RMS value data in stages; Multiplying each of the RMS values classified by the step by a stepwise weight value; And calculating a service life of the spindle by summing values obtained by multiplying the RMS values classified by the step by the weight values of the step, and calculating the service life of the spindle.

Further, the present invention is characterized by comprising: comparing the service life of the spindle with the life span of the spindle; Determining whether a service life of the spindle is close to a life span of the spindle; And providing an alarm to the user about the life spindle of the spindle when the service life is close to the life expectancy of the spindle.

The present invention further provides a method of diagnosing the life span of a spindle of a multi-axis machine, wherein the data of the RMS value is sorted in stages according to the range of vibration data displacement values.

In the present invention, the RMS value data is classified into stages, taking into consideration the characteristic that the influence on the life spindle of the spindle is different according to the displacement of the vibration generated in the spindle, and the stepwise weight value is divided into the stepwise RMS value , It is possible to more precisely calculate the service life of the spindle by applying the displacement component of the vibration generated in the spindle to the service life of the spindle.

The present invention also compares the service life of such a spindle with the spindle's unique life span, so that when the service life of the spindle approaches the limit of service life of the spindle, Can be replaced.

1 is a perspective view showing a multi-axis processing machine according to the present invention.
FIG. 2A is a schematic block diagram for explaining a life span diagnosis system of a spindle of a multi-axis processing machine according to the present invention.
2B is a block diagram showing a configuration of a signal processing module according to the present invention.
3A is a diagram showing an example of a kurtosis graph by the statistical processing module.
3B is a diagram showing an example of a root-mean-square root (RMS) graph by the statistical processing module.
3C is a diagram showing an example of a mean graph of the vibration displacement of the acceleration data by the statistical processing module.
4 is a schematic flow chart for explaining a method of diagnosing the life span of a spindle of a multi-axis processing machine according to the present invention.
5 shows an example in which the service life of the spindle is calculated.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. &Quot; and / or "include each and every combination of one or more of the mentioned items. ≪ RTI ID = 0.0 >

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a multi-axis processing machine according to the present invention.

First, as shown in FIG. 1, a multi-axis processing machine according to the present invention, for example, a five-axis processing machine 100 includes a T-bed 110, (110a) and a second directional bed (110b) arranged in a direction perpendicular to the first directional bed (110b).

The 5-axis processing machine 100 according to the present invention includes an X-base 120 disposed on a first directional bed 110a of the T-bed 110, and the X- Includes an X-axis rail (121) disposed on the X-base (120).

The X-axis rail 121 includes an X-axis first rail 121a and an X-axis second rail 121b disposed in parallel with the X-axis first rail 121a.

For convenience of explanation, the X-axis first rail 121a is defined as a front rail, and the X-axis second rail 121b is defined as a back rail.

1, a five-axis machining apparatus 100 according to the present invention includes a table 130 disposed on the X-axis rail 121. The table 130 is a table for positioning an object to be processed And a support plate 131.

At this time, the table 130 is disposed on the X-axis rail 121 and can move in the X-axis direction.

The 5-axis processing machine 100 according to the present invention includes a column 140 disposed above the second directional bed 110b of the T-bed 110. At this time, Axis rail 111. The Y-

The Y-axis rail 111 includes a Y-axis second rail 111b disposed in parallel with a Y-axis first rail (not shown) and a Y-axis first rail (not shown).

However, for convenience of explanation, the Y-axis first rail (not shown) is defined as a left rail, and the Y-axis second rail 111b is defined as a right rail.

In the above description, the Y-axis rail 111 is included in the lower portion of the column 140. However, the Y-axis rail 111 may be formed on the upper portion of the second directional bed 110b of the T- Axis column 111 and the column 140 is disposed on the Y-axis rail 111. As shown in FIG.

At this time, the column 140 is disposed on the Y-axis rail 111 and can move in the Y-axis direction.

Also, as shown in FIG. 1, the Z-axis rail 141 is included in a certain region of the side surface of the column 140.

At this time, the Z-axis rail 141 includes a Z-axis first rail 141a and a Z-axis second rail 141b disposed in parallel with the Z-axis first rail 141a.

1, a five-axis machining apparatus 100 according to the present invention includes a spindle 150 disposed on the Z-axis rail 141 of the column 140, wherein the spindle 150 ) Can move in the Z-axis direction.

In addition, the 5-axis machining apparatus includes a tool, and the tool rotates while mounted on the spindle 150 to perform a cutting operation on the workpiece.

At this time, the tool may be an end mill, a milling tool, a drill tool, or a boring tool, but does not limit the kind of the tool in the present invention.

On the other hand, as described above, in the case of a spindle to which a tool is fastened in a multiaxial machining apparatus, if an abnormality occurs, it can lead to enormous economic loss and personal injury.

Such an abnormality may occur excessively at the time of using the spindle continuously even though the spindle has reached the end of its service life. Therefore, it is necessary to diagnose and periodically replace or repair the service life of the spindle.

Hereinafter, a spindle life span diagnosis system and a life span diagnosis method of a multi-axis machining apparatus according to the present invention will be described.

FIG. 2A is a schematic block diagram for explaining a life span diagnosis system of a spindle of a multi-axis processing machine according to the present invention.

Referring to FIG. 2A, a spindle life span diagnosis system 200 of a multi-axis machine according to the present invention includes a measurement instrument 210 provided in a predetermined region of a spindle to be subjected to a life span diagnosis, A signal processing module 220 for performing signal processing of the measurement data and a signal analysis module 230 for providing schedule information based on the measurement data.

The measuring instrument 210 can measure acceleration data from the vibration of the spindle and transmit it.

For example, the measuring instrument 210 may include an acceleration sensor 211 and a data logger.

At this time, in case of the acceleration sensor 211, if the analog type data to be outputted is transmitted to a remote data logger, it can be influenced by external noise, so that it can be configured as a digital output type so that the influence of external noise can be minimized .

Also, the acceleration sensor 211 may be a semiconductor type MEMS (Micro Electro Mechanical System) capable of being integrated with a CMOS circuit and having low power consumption, temperature characteristics, and DC characteristics; Microelectronic control technology) Acceleration sensor is applied to measure the acceleration. Such a MEMS acceleration sensor can be configured as a three-axis acceleration sensor capable of simultaneously measuring horizontal two-component and vertical one component, You can use a differential output scheme that removes the noise that can be induced.

The data logger may transmit the acceleration data measured by the acceleration sensor 211 to the signal processing module 220 according to a defined communication protocol.

The signal processing module 220 receives the acceleration data transmitted from the measuring instrument 110 and performs FFT (Fast Fourier Transform) analysis on the input acceleration data to pass only the components of the required frequency band and output the data. Signal processing such as sampling and noise cancellation can be performed.

The signal analysis module 230 can provide various monitoring information by performing analysis through an analysis algorithm using the acceleration data processed by the measurement device 210 or the signal processing module 220.

For example, the signal analysis module 230 may analyze the PGA (Peak Ground Acceleration), the MMA (Min, Max, Avg) data presentation, the power spectrum, and the response spectrum (acceleration / Analysis function. ≪ / RTI >

The signal analysis module 230 can select an analysis target time point or a target time point according to a request command inputted from the outside and provide analysis data for a selected time point or a time period, Vibration evaluation can be performed.

2B is a block diagram showing a configuration of a signal processing module according to the present invention.

2B, the signal processing module 220 performs data processing including filtering and sampling on data before analyzing vibration acceleration data received from the measuring instrument 210 can do.

More specifically, the signal processing module 220 may include a filtering unit 221 and a sampling unit 222.

A digital filter can be applied to the filtering unit 221. When the input signal (acceleration data) is input, the digital filter removes an undesired frequency band based on a result of performing an FFT (Fast Fourier Transform) It is possible to output only the component of the desired frequency band.

For example, the filtering unit 221 may use any one of LPF (Low Pass Filtering), HPF (High Pass Filtering), and BPF (Band Width Pass Filtering) The quality can be improved.

The sampling unit 222 may perform sampling on an input signal (acceleration data).

Sampling in signal processing means extracting analog data into digital data.

At this time, the signal analysis module 230 can analyze the dynamic characteristics of the object by analyzing the maximum amplitude and the natural period from the amplitude of the vibration signal of the spindle, calculate the response spectrum, and compare the response spectrum with the design spectrum. Further, the vibration velocity may be calculated from the acceleration data, and the vibration displacement and the absolute absolute velocity may be calculated.

Meanwhile, although not shown in the drawing, the signal analysis module 230 is provided with an output interface for outputting the analyzed information, and is connected to a display device so that the analyzed information is provided as an image including a graph or graphic form can do.

2A, a spindle life span diagnosis system 200 of a multi-axis machine according to the present invention includes a statistical processing module 240 for processing data transmitted from the signal processing module 220 and performing statistical processing, .

That is, the statistical processing module 240 may update the statistical database by performing statistical processing on the collected data according to a predetermined period.

At this time, the setting period of the statistical processing module 240 can be selectively designated by the user. For example, the setting period is set in minutes, hours, days, weeks, Information can be provided.

As described above, the statistical data provided by the statistical processing module 240 is obtained by processing the data transmitted from the signal processing module 220. The statistical data provided by the statistical processing module 240 includes average data of the vibration displacement with respect to the acceleration data, A kurtosis, a skewness, and a square root mean square (RMS).

3A is a diagram showing an example of a kurtosis graph by the statistical processing module.

The kurtosis shown in FIG. 3A indicates the degree of convergence of the acceleration data collected for a predetermined time from the acceleration sensor 211 around the arithmetic mean. The statistical processing module 240 can calculate the kurtosis according to the following equation have.

(1)

In Equation (1), K is the kurtosis, X is the signal value, n is the number of samples of the signal, μ is the mean of the signal values, and σ is the standard deviation of the signal values . ≪ / RTI >

3B is a diagram showing an example of a root-mean-square root (RMS) graph by the statistical processing module.

The root-mean-square (RMS) square is a squared average of the acceleration data collected from the acceleration sensor 211 for a predetermined period of time. It is a statistical measure of the magnitude of the changing value. When the variables come and go, such as a sine function useful.

The statistical processing module 240 may calculate the root-mean-square (root-mean-square) by the following equation (2).

(2)

In Equation (2), RMS is a root-mean-square root, a is a signal value, and n is the number of samples of the signal (the entire sample object collected during the predetermined period by the acceleration sensor).

3C is a diagram showing an example of a mean graph of the vibration displacement of the acceleration data by the statistical processing module.

The mean of the acceleration data can be calculated by deriving an average value of the vibration displacement with respect to the acceleration data of all the samples collected during the predetermined time by the acceleration sensor.

According to the spindle lifetime diagnosis system of the multi-axis machining apparatus, data on the operating characteristic factors of the spindle can be collected by the vibration characteristics of the spindle.

4 is a schematic flow chart for explaining a method of diagnosing the life span of a spindle of a multi-axis processing machine according to the present invention.

Referring to FIG. 4, a method for diagnosing the life span of a spindle of a multiaxial machining apparatus according to the present invention includes collecting data on operation characteristic factors of a spindle (S110).

In this case, the operating characteristic factors may be mean, standard deviation, skewness, kurtosis, root-mean-square (RMS) of the vibration displacement of the machine tool.

As described above, the operation characteristic factors may be provided in the statistical processing module 240 that processes the data transmitted from the signal processing module 220 and performs statistical processing.

3, a method for diagnosing the service life of a spindle of a multi-axis processing machine according to the present invention includes deriving an RMS value of data values for the operation characteristic factors, and classifying the RMS value data in stages (S120).

That is, the RMS value is calculated from the data values such as mean, standard deviation, skewness, kurtosis, and root-mean-square of the vibration displacement provided by the statistical processing module 240 In the present invention, the life of the spindle of the multi-axis processing machine is diagnosed through the RMS value.

In the present invention, the RMS value of the vibration data displacement value is classified according to various vibration data sections.

For example, the data of the RMS value may be classified into the first section RMS value to the seventh section RMS value step by step.

Since the influence of the vibration on the spindle varies depending on the displacement of the spindle due to the displacement of the spindle, classification of the interval is performed to classify the data of the RMS value step by step so as to assign a relative weight to each step.

For example, when the vibration data displacement value is in the range of 0.01 to 0.02 mm, it is defined as the first section RMS value, and when the vibration data displacement value is in the range of 0.02 to 0.05 mm, it is defined as the second section RMS value However, the present invention is not limited to the example of the range of the displacement value of the vibrating decker, and it is also possible that the user sets the RMS value for each multi- .

Referring to FIG. 4, the method for diagnosing the service life of the spindle of the multiaxial machining apparatus according to the present invention includes multiplying each of the RMS values classified by the step by a stepwise weight value (S130).

As described above, in the present invention, the influence of the vibration on the spindle on the life of the spindle varies depending on the displacement of the spindle, so the data of the RMS value is sorted in stages.

Then, by multiplying the stepwise RMS values by the different weights, i.e., the stepwise weights, the influence of the vibration generated on the spindle on the spindle life can be grasped according to the RMS values for each step.

For example, the first interval RMS value is multiplied by the first weight, the second interval RMS value is multiplied by the second weight, and the seventh interval RMS value is multiplied by the seventh weight.

More specifically, stepwise weights are selected in such a manner that the first weight is 1s, the second weight is 2s, and the seventh weight is 10s. For example, during operation of the multi-axis machine, In the case of the range of 0.01 to 0.02 mm, since it corresponds to the first section RMS value, the first weight is multiplied, and when the displacement of the vibration generated in the current spindle is in the range of 0.02 to 0.05 mm, it corresponds to the second section RMS value. 2 Weights are multiplied.

However, the present invention is not limited to the example of the stepwise weight value, and the user can set the weight value stepwise for each multi-axis machine.

4, the method for diagnosing the service life of a spindle of a multiaxial machining apparatus according to the present invention includes calculating the service life of the spindle by summing values obtained by multiplying the RMS values classified by the above step by the stepwise weight values (S140).

That is, during the operation of the multi-axis machine, the RMS value for each step is selected according to the displacement of the vibration generated in the current spindle, and the result is multiplied by the weight value for each step. Can be calculated.

This service life can be expressed as Equation (3) below.

In Equation (3), w1, w2, ... , wn (n is an integer) is a step weight value, y1, y2, ... , and yn (n is an integer) can be defined as a stepwise RMS value.

According to the above-described method, in the present invention, the service life up to the present according to the operation of the multi-axis processing machine can be calculated.

In calculating the useful life of the spindle, the data of the RMS value may be classified in stages, taking into consideration the characteristic that the influence on the life of the spindle varies depending on the displacement of the vibration generated in the spindle, By multiplying the stepwise RMS value, the service life of the spindle can be calculated more accurately by applying the displacement component of the vibration generated in the spindle to the service life of the spindle.

5 shows an example in which the service life of the spindle is calculated.

As shown in FIG. 5, it is possible to calculate the service life according to the operation of the multiaxial machining apparatus by selecting the stepwise RMS value according to the displacement of the vibration, multiplying the stepwise weight value by the value, and summing the values.

Referring to FIG. 4, a method for diagnosing the life span of a spindle of a multi-axis processing machine according to the present invention includes comparing the service life of the spindle with the life span of the spindle (S150).

That is, by calculating the service life of the spindle up to the present time by the above-described steps S110 to S140 and comparing the service life with the inherent service life of the spindle, It can be confirmed whether or not it is close to the natural life.

Referring to FIG. 4, it is determined whether or not the service life of the spindle is close to the service life of the spindle (S160). If the service life is close to the service life of the spindle, (S170).

That is, when the service life of the spindle is close to the limited service life of the spindle, it means that the replacement time of the spindle has come. Therefore, by providing the service life of the spindle to the user through an alarm, the user can proceed to replace the spindle .

In addition, when the service life of the spindle is not close to the limit service life of the spindle, the service life of the spindle up to the present can be continuously calculated by continuously performing steps S110 to S140.

As described above, in the case of a spindle to which a tool is fastened in a multiaxial machining apparatus, if an abnormality occurs, it can lead to enormous economic loss and personal injury.

Such an abnormality may occur excessively at the time of using the spindle continuously even though the spindle has reached the end of its service life. Therefore, it is necessary to diagnose and periodically replace or repair the service life of the spindle.

However, in the present invention, data of the RMS value is classified into stages, considering the characteristic that the influence on the life of the spindle differs according to the displacement of vibration generated in the spindle, and the step weight value is multiplied by the stepwise RMS value , It is possible to more precisely calculate the service life of the spindle by applying the displacement element of the vibration generated in the spindle to the service life of the spindle.

In addition, by comparing the service life of such a spindle with the spindle specific life span, if the service life of the spindle is close to the limit of life of the spindle, by providing the user with such a service life of the spindle via an alarm, You can proceed.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (7)

In a spindle life diagnosing system for a multi-axis processing machine,
The spindle life span diagnosis system of the multi-
A measuring instrument provided in a predetermined region of the spindle;
A signal processing module for performing signal processing of measurement data output from the measuring instrument;
A signal analysis module for providing schedule information based on measurement data; And
And a statistical processing module for processing the data transmitted from the signal processing module and performing statistical processing,
The statistical data provided by the statistical processing module includes an RMS value of the vibration displacement for the acceleration data,
The spindle life span diagnosis system of the multi-
The RMS value data is classified into stages, and each RMS value classified by the step is multiplied by a step weight value. Then, the RMS values classified by the step are multiplied by the stepwise weight values, Lt; / RTI >
Wherein the service life of the spindle is expressed by the following equation (3).
(3)

W2, ..., wn (n is an integer) in the equation (3) is defined as a stepwise weight value, y1, y2, ..., yn (n is an integer) defined as a stepwise RMS value. delete The method according to claim 1,
Wherein the measuring instrument includes an acceleration sensor and a data logger. Collecting data on operating characteristic parameters of the spindle;
Deriving an RMS value of data values for the operation characteristic factors, and classifying the RMS value data in stages;
Multiplying each of the RMS values classified by the step by a stepwise weight value; And
Calculating a service life of the spindle by summing values obtained by multiplying the respective RMS values classified by the step by the stepwise weight value,
The step of classifying the data of the RMS value stepwise comprises:
The data of the RMS value is classified in stages according to the range of the vibration data displacement value,
Wherein the service life of the spindle is expressed by the following equation (3): " (3) "
(3)

W2, ..., wn (n is an integer) in the equation (3) is defined as a stepwise weight value, y1, y2, ..., yn (n is an integer) defined as a stepwise RMS value. 5. The method of claim 4,
Comparing the service life of the spindle with the service life of the spindle;
Determining whether a service life of the spindle is close to a life span of the spindle; And
Further comprising the step of providing the user with an alarm on the life spindle of the spindle if the service life is close to the life expectancy. delete delete

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