KR102144420B1 - Monitoring system for cutting system using intelligent cutting simulation and Monitoring method using thereof - Google Patents

Abstract

The present invention discloses a system and method for monitoring a machining process by simulating the shape, cutting force, vibration, and wear of the workpiece when machining a workpiece in 3D, and comparing the predicted value of the simulated result with the measured value measured by the machining system.
The machining process monitoring system of the present invention receives the highest cutting force and highest vibration value extracted from the simulation control unit as a cutting force predicted value and a vibration predicted value, and compares the cutting force measurement value and vibration measured value measured in the machining system to measure the cutting force rather than the predicted cutting force and vibration predicted value. And if the vibration measurement is large, the operation of the processing system can be stopped.

Description

Processing process monitoring system using intelligent machining simulation, and monitoring method using the same {Monitoring system for cutting system using intelligent cutting simulation and Monitoring method using thereof}

The present invention relates to a method for monitoring a machining process by simulating the shape of the workpiece, cutting force, vibration, and abrasion amount, etc., and comparing the predicted value of the simulated result with the measured value measured by the machining system when machining the workpiece in 3D.

In general, a virtual CNC milling machine can predict the machining shape of a workpiece through simulation by entering a CNC program. Such a conventional virtual CNC milling machine simulates a machining shape of a workpiece by reading coordinates from a CNC program and mathematically processing a Boolean operation.

10 is a flow chart illustrating an example of verifying a processing shape through a conventional virtual CNC milling machine. A tool shape, a work piece shape, and a cutting condition are input to the virtual CNC milling machine (S101). Then, input the G code, X, Y, Z coordinate values of one block in the CNC program (S103). Then, the virtual CNC milling machine calculates the volume of the entire block of the CNC program and erases the calculated volume (S105). That is, as shown in Fig. 11, the calculated volume V is erased by calculating the volume V to be erased of the work W. And the virtual CNC milling machine outputs the processed shape on the screen (S107). Then, the operator can determine whether the processed shape fits the purpose. In addition, it is determined whether the entire block of the CNC program is finished (S109), and if the block of the entire CNC program is not finished, steps S103 to S107 are repeated.

Such a conventional virtual CNC milling machine cannot predict the machining defects of the workpiece caused by tool breakage, wear and vibration caused by excessive cutting that occurs in the actual machining phenomenon, and is processed by comparing the cutting force and vibration predicted values with the cutting force and vibration measurements. There is a problem that the process cannot be monitored.

Korean Patent Application Publication No. 10-2015-0075742 (published on July 6, 2015) Korean Registered Patent Publication No. 10-1638623 (announced on July 11, 2016)

Accordingly, the present invention has been proposed to solve the above problems, and an object of the present invention is to calculate the volume per tooth in one block of the CNC program and calculate the cutting force using this to optimize the machining conditions of the CNC program, A machining simulation system for workpieces that predicts wear and vibration acting on the tool to reduce tool breakage due to excessive cutting of the workpiece during actual machining, reduce machining defects caused by wear and vibration, and at the same time improve machining precision. It is to provide a method for monitoring the processing process using this. That is, it is to provide a method of monitoring the state of the machining process by comparing the cutting force and vibration measurements in the actual machining system with the cutting force and vibration predicted values predicted in the simulation.

In order to achieve the object of the present invention as described above, the present invention

The machining simulation system

An input unit that receives the shape of the tool, the shape of the workpiece, the cutting conditions and the code of each block in the CNC program, the coordinate values of the tool's X, Y, Z, the feed rate of the tool, and the spindle rotation speed data,

A simulation control unit that calculates a cutting force using data from the input unit,

A basic data storage unit that is input and output by the simulation control unit and stores data input through the input unit or optimizes and stores coordinate values, feed rates, and spindle speeds in the CNC program,

Includes an output unit for outputting a processing simulation shape of the workpiece by using the cutting force calculated by the simulation control unit,

The simulation control unit

By calculating the chip volume per tooth in each block of the CNC program, the calculated chip volume per tooth is erased, and the cutting force per tooth is calculated using the chip volume per tooth,

A chip volume calculation unit per blade that calculates the chip volume per blade of the tool,

A cutting force calculation unit per blade that calculates the cutting force of the tool by using the value calculated by the chip volume calculation unit per blade,

A vibration value calculation unit that calculates the vibration value of the tool by using the value calculated by the chip volume calculation unit per blade, and

And an extraction unit for extracting the highest cutting force from the values calculated by the cutting force per blade calculation unit, and extracting the highest vibration value from the values calculated by the vibration value calculation unit,

The highest cutting force and the highest vibration value extracted from the simulation control unit are input as a cutting force predicted value and a vibration predicted value, and the cutting force measured value and the vibration measured value are compared to the cutting force predicted value and the vibration predicted value. When is large, it provides a processing process monitoring system that stops the operation of the processing system.

The processing process monitoring system

Using a sensor compensation value loading unit that loads the sensor compensation value of the input cutting force and the sensor compensation value of the vibration, a current signal measurement unit that measures the cutting force of the processing system, the current signal measurement unit value and the sensor compensation value of the cutting force. A cutting force calculation unit that calculates the cutting force, an acceleration measurement unit that measures the vibration of the processing system, a vibration calculation unit that calculates vibration using a value of the acceleration measurement unit and a sensor compensation value of the vibration, and the cutting force of the machining simulation system A monitoring determination unit that compares the predicted value and vibration predicted value with the cutting force measurement value calculated by the cutting force calculation unit and the vibration measurement value calculated by the vibration calculation unit, and the cutting force measurement value and the cutting force measurement value and the vibration predicted value in the monitoring determination unit. When the vibration measurement value is large, it is preferable to include an alarm control unit that receives the signal and performs control to stop the processing system.

In addition, the present invention

The simulation control unit of the machining simulation system

The step of receiving the shape of the tool, the shape of the workpiece, and the cutting conditions,

After the step of receiving the shape of the tool, the shape of the workpiece, and the cutting conditions, the code of one block, the coordinate values of X, Y, Z of the tool, the feed rate of the tool, and the spindle rotation speed are sequentially determined in the CNC program. Loading from the basic data storage unit,

Calculating the cutting force of the tool after reading the code of the one block, the coordinate values of X, Y, Z of the tool, the feed rate of the tool, and the rotational speed of the spindle,

Determining whether the tool collides with the work piece or excessive cutting force occurs after calculating the cutting force of the tool,

In the step of determining whether the tool collides with the work or excessive cutting force occurs, outputting a warning message when the tool collides with the work or generates excessive cutting force,

After the step of determining whether the tool collides with the work piece or excessive cutting force occurs, if the tool does not collide with the work piece or does not generate excessive cutting force, it is determined whether one block of the CNC program is over and one block is not finished. If not, determining the end of performing the block moving to before the step of calculating the cutting force,

In the step of determining the end of the block execution, when the execution of one block is completed, extracting the highest cutting force and the highest vibration value generated in the process,

After the step of extracting the highest cutting force and the highest vibration value, outputting the processed shape output, the highest cutting force, and the highest vibration amplitude, and storing it in a data storage unit, and

After the step of outputting the processing shape output, the highest cutting force, and the highest vibration amplitude, and storing it in the data storage unit, check if all the CNC programs have been executed, and if all CNC programs have been executed, terminate the program, and if the execution is not completed, the In the CNC program, a block of G code, X, Y, Z coordinate values, feed speed, and spindle speed are returned to the previous step of receiving input,

The step of calculating the cutting force

By calculating the chip volume per tooth in one block of the CNC program, the volume of the virtual workpiece is eliminated and the cutting force is calculated.

The simulation control unit converts the cutting force peak value and the vibration peak value, respectively, to a cutting force predicted value and a vibration predicted value, and transmits it to a processing process monitoring system,

The processing process monitoring system

Loading the sensor compensation value of the input cutting force and the sensor compensation value of the vibration,

After the step of loading the sensor compensation value, measuring and measuring the current signal and acceleration of the machining system to calculate the cutting force and vibration of the machining system,

After measuring the cutting force and vibration of the processing system, calculating the cutting force and vibration using the value of the current signal measuring unit and the sensor compensation value of the cutting force,

After calculating the cutting force and vibration, receiving a cutting force predicted value and a vibration predicted value of the processing simulation system and comparing the cutting force measurement value and the vibration measurement value to determine whether the cutting force measurement value and the vibration measurement value are large, and

After determining whether the cutting force measurement value and the vibration measurement value are greater than the cutting force predicted value and the vibration predicted value, if the cutting force measurement value and the vibration measurement value are greater than the cutting force predicted value and the vibration predicted value, performing control to stop the processing system. Provides a monitoring method.

In the past, only the shape of the workpiece was predicted, but the embodiment of the present invention simulates the machining shape by removing the chip volume per tooth in the same way as the cutting situation of an actual milling machine, and accurately predicts the cutting force of the tool. The cutting situation can be accurately verified before machining of the machine and the precision of the workpiece after machining can be improved by optimizing the CNC program, and the cutting system can be monitored by comparing the measured value of the cutting system with the predicted value of the simulation.

1 is a block diagram showing a machining system, a machining simulation system of a workpiece, and a machining process monitoring system to describe an embodiment of the present invention.
2 is a block diagram showing a machining process simulation system applied to the present invention.
3 is a flow chart for explaining a processing process simulation process applied to the present invention.
4 is a diagram showing a cutting force per edge of a tool in the machining process simulation system applied to the present invention and output to the display.
5 is a view showing a CAD model and a shape verified by a virtual CNC program as a result of verification of the machining process simulation system applied to the present invention.
6 is a diagram illustrating a cutting force per edge of the machining process simulation system applied to the present invention and output to the display.
7 is a block diagram showing a processing process monitoring system of the present invention.
8 is a flow chart for explaining the processing process monitoring process of the present invention.
9 is a view showing the diameter and length of the tool to explain the embodiment of the present invention.
10 is a flowchart illustrating a method of predicting a machining shape using a conventional virtual CNC milling machine.
11 is a diagram showing contents of erasing the volume of a workpiece according to the prior art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily practice. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are assigned to the same or similar components throughout the specification.

In the machining process simulation system applied to the embodiment of the present invention, a virtual tool is indicated by T and a virtual workpiece is indicated by W.

1 is a block diagram for explaining an embodiment of the present invention, a machining system 1, a machining simulation system for a workpiece (3, hereinafter, referred to as a'machining simulation system' or'simulation system'), and a machining process monitoring system (5, hereinafter referred to as a'monitoring system') is shown.

The machining system 1 is a machine tool for cutting using a tool. The processing system 1 includes a machine tool control unit 11, a current measurement sensor 13, an acceleration sensor 15, and an alarm display unit 17.

The machine tool control unit 11 may directly control a feed speed of a main shaft to which a tool for machining a work is coupled using input data required for machining a work. In addition, the machine tool control unit 11 is controlled by the machining process monitoring system 5 when the actual measured value is larger than the predicted value by comparing the predicted cutting force value and the measured value of cutting force in the machining process monitoring system 5 or comparing the predicted value of vibration and the measured value of vibration. The processing system 1 can be stopped by receiving a signal.

The current measurement sensor 13 is a sensor capable of measuring an actual cutting force of a tool of a machine tool. The current measurement sensor 13 may transmit the measured sensing value to the processing process monitoring system 5. And the acceleration sensor 15 is a sensor capable of measuring the actual vibration of the tool of the machine tool. The acceleration sensor 15 may transmit the measured sensing value to the processing process monitoring system 5.

The alarm display unit 17 may be a buzzer or a warning lamp, and may be operated by a signal determined by the processing process monitoring system 5. That is, the alarm display unit 17 may be operated by receiving a control signal when the actual measurement value is larger than the predicted value by comparing the predicted cutting force value and the measured value of cutting force in the processing process monitoring system 5 or comparing the predicted value of vibration and the measured value of vibration.

The machining simulation system 3 of a work piece may include an input unit 31, a simulation control unit 33, an output unit 35, and a data storage unit 37.

The input unit 31 may receive a shape of a tool, a shape of a work, and a cutting condition by a user and store it in the data storage unit 37. In addition, through the input unit 31, the code of each block, the coordinate values of X, Y, and Z of the tool, the feed rate of the tool, and the spindle rotation speed data may be input from the CNC program. These input values may be stored in the data storage unit 37 by the simulation control unit 33.

The simulation control unit 33 may calculate the cutting force by using the data input through the input unit 31, and store or load the data inputted in the data storage unit 37 to transfer the calculated value to the output unit 35. Can be printed. In particular, the simulation controller 33 may calculate the cutting force by calculating the chip volume per tooth in each block of the CNC program and erasing the calculated chip volume per tooth.

The simulation control unit 33 includes a data loading unit 131, a chip volume per blade calculation unit 133, a cutting force per blade calculation unit 135, a vibration value calculation unit 137, a tool wear amount calculation unit 139, and It may include an extraction unit 141 for extracting the cutting force and the highest vibration value, and a storage and output unit 143 for storing and outputting the processing simulation shape of the workpiece.

The data loading unit 131 may serve to load data stored in the data storage unit 37.

The chip volume per blade calculation unit 133 may calculate and obtain the volume of chips cut by one blade of the tool. The chip volume per day calculation unit 133 may calculate the chip volume per day (S _th ) by the following calculation formula.

That is, the chip volume per blade (S _th ) is,

Is represented by

이고,

는 날 당 절삭시간이며,Where s _p is the volume removed during each sampling simulation time d t ,

ego,

Is the cutting time per edge,

는,Cutting time per edge

Is,

로 표시되며,

Is represented by

는 공구의 날 수이다.Where S is the spindle speed (rpm),

Is the number of teeth of the tool.

The cutting force per edge calculation unit 135 may calculate the cutting force per edge ( F _th ) of the tool by using the chip volume per edge ( S _th ). The cutting force per edge ( F _th ) of the tool through the cutting force calculation unit 135 per edge may be expressed by the following calculation formula.

The volume compensation ratio is calculated as follows in order to increase the accuracy of the calculation of the cutting force.

The vibration value calculation unit 137 may calculate a vibration value of the tool generated in the process of processing the virtual workpiece. The vibration value calculated by the vibration value calculation unit 137 is as follows.

If the cutting system by the tool is modeled as a vibration system, the vibration equation is as follows.

Here, the spring constant k is obtained as follows using the tool diameter and the tool length as shown in FIG. 9.

This vibrational equation can be modeled with a multi-DOF system. In the case of one degree of freedom, the displacement x (t) in the steady state of the forced vibration system by the predicted cutting force F _t is as follows.

는 위상이고, 고유주파수는 다음과 같다. Where X ₀ is the amplitude of the vibration,

Is the phase, and the natural frequency is as follows.

Output amplitude X ₀ as vibration value.

The tool wear amount calculation unit 139 calculates the expected tool wear amount when machining an actual work piece, and the tool wear amount W may be calculated by the following equation.

That is, the tool wear amount ( W ) is

It can be calculated by the formula of

The extraction unit 141 for extracting the highest cutting force and the highest vibration value (meaning the amplitude value) is the highest cutting force and highest vibration among the values calculated by the above-described cutting force calculation unit 135 and vibration value calculation unit 137. The value may be extracted and stored in the data storage unit 37.

The maximum cutting force may be extracted by comparing the cutting force per edge calculated by the cutting force per edge calculating unit 135 to extract the largest cutting force. Also, the highest vibration value may be extracted by comparing the values calculated by the vibration value calculator 137.

Since these maximum cutting force and maximum vibration values are factors that actually affect the machining of the work piece, through these values, it is possible to prevent machining defects or improve machining precision by removing expected problems when machining an actual work piece in advance.

The processing simulation shape storage and output unit 143 of the work piece uses the result value calculated by the above-described calculation method to image the virtually processed shape and stores it in the data storage unit 7 and through the output unit 5 Can be output (see Figs. 5 and 6). That is, the processing simulation shape storage and output unit 143 of the work piece may store and output the value calculated by the simulation control unit 33 so that the operator can check it and reflect it when processing the actual work piece.

The output unit 35 may include a printer 151 and a display 153. The printer 151 may be a general output device printed on paper, and the display 153 may be a monitor connected to a computer.

The data storage unit 37 may include a basic data storage unit 171, a cutting force data storage unit 173, a vibration value data storage unit 175, and a tool wear amount data storage unit 177.

The basic data storage unit 171 may store a tool shape, a work piece shape, and a cutting condition input through the input unit 31. In addition, the basic data storage unit 171 may store G code values, X, Y, Z coordinate values, tool feed rates, and spindle speeds of each block in the CNC file. Here, the feed speed and the spindle speed can output the optimum values adjusted so that the cutting force is constant.

The cutting force data storage unit 173 may store values calculated by the cutting force calculation unit 135 of the simulation control unit 33.

The vibration value data storage unit 175 may store values calculated by the vibration value calculation unit 137 of the simulation control unit 33.

Similarly, the tool wear amount data storage unit 177 may store values calculated by the tool wear amount calculation unit 139 of the simulation control unit 33.

A detailed description of the machining simulation method of the work piece applied to the embodiment of the present invention made as described above with reference to FIGS. 2 and 3 is as follows.

First, the user inputs the shape of the tool, the shape of the workpiece, and the cutting condition through the input unit 31, and the code of one block sequentially in the CNC program, the coordinate values of X, Y, Z of the tool, and the transfer of the tool. The speed and spindle rotation speed can be entered (S1). Data input through the input unit 31 may be stored in the basic database 171 of the data storage unit 37.

Then, the data loading unit 131 of the simulation control unit 33 is in the basic data storage unit 171, the shape of the tool, the shape of the workpiece, the cutting conditions and the code of one block sequentially in the CNC program, X, Y of the tool. , The coordinate value of Z, the feed rate of the tool, and the spindle rotation speed are loaded (S3).

Then, the simulation control unit 33 calculates the cutting force of the tool (S5). At this time, the cutting force of the tool is calculated by calculating the chip volume per edge in one CNC program block, erasing the chip volume (see Fig. 4), and calculating the cutting force using this chip volume. Here, the chip volume per blade is calculated by the chip volume per blade calculation unit 133 of the simulation control unit 33, and the chip volume calculation formula per blade is made of the calculation formula presented in the above-described chip volume calculation unit 133. In addition, the cutting force per edge is calculated by the cutting force per edge calculation unit 135 of the simulation control unit 33, and the calculation formula may be formed by the calculation formula described in the cutting force per edge calculation unit 135 described above.

In the embodiment of the present invention, the cutting force per edge is preferably calculated using the chip volume per edge.

The cutting force per edge calculated by the cutting force per edge calculation unit 135 of the simulation control unit 33 is preferably stored in the cutting force data storage unit 173 of the data storage unit 37. The data stored in the cutting force data storage unit 173 determines whether excessive cutting force is generated by extracting the highest cutting force from the highest cutting force and highest vibration value extracting unit 141 of the simulation control unit 33 (S7). The maximum cutting force may be extracted by comparing the maximum cutting force of the simulation control unit 33 with the cutting force data stored in the cutting force data storage unit 173 by the maximum vibration value extracting unit 141.

In addition, in the step (S7) of determining whether the above-described excessive cutting force occurs, it may be determined whether the tool collides with the workpiece by the feed speed of the tool.

In the step (S7) of determining whether the tool collides with the work or excessive cutting force occurs, a warning message is output through the display 153 of the output unit 35 when the tool collides with the work or excessive cutting force occurs. (S9). At this stage, the warning message may be stored in the basic database 171.

Subsequently, after the step (S7) of determining whether the tool collides with the virtual workpiece or excessive cutting force occurs, the simulation control unit 33 determines whether the tool collides with the virtual workpiece or generates excessive cutting force. A block execution end step of determining whether the block is over is performed (S11). If one block is not finished in this step (S11), it moves to the step (S5) of calculating the cutting force.

When the execution of one block is finished in the step (S11) of determining the completion of the block execution described above, the highest cutting force and the highest vibration value generated in the process are extracted, and the tool wear amount is calculated (S13).

The highest cutting force and highest vibration value extraction unit 141 of the simulation control unit 33 converts the extracted highest cutting force into a predicted cutting force and transmits the predicted cutting force to the machining process monitoring system 5 (S14, indicated by A in FIG. 3 ). box). In addition, the highest cutting force and highest vibration value extraction unit 141 of the simulation control unit 33 converts the extracted highest vibration value into a vibration value predicted value and transmits the vibration value predicted value to the machining process monitoring system 5 (S14, FIG. 3 to A)

In addition, the cutting force calculation unit 135 of the simulation control unit 33 stores the cutting force data calculated by the above-described equation in the cutting force data storage unit 173, and the tool calculated through the vibration value calculation unit 137 The vibration value of is stored in the vibration value data storage unit 175, and the data calculated by the tool wear amount calculation unit 139 is stored in the tool wear amount data storage unit 177.

After the step (S14) of continuously transmitting the extracted peak cutting force predicted value and the extracted peak vibration value to the monitoring system 5 (S14), the processed shape output, the highest cutting force, the highest vibration size, and the amount of tool wear are output to the output unit 35 and data It is stored in the storage unit 37 (S15).

And after the step (S15) of outputting the machining shape output, the highest cutting force, the highest vibration size, and the amount of tool wear and storing it in the data storage unit (S15), it is determined whether all the CNC programs have been executed. If this is not completed, the CNC program moves to the previous step (S3) of receiving one block of G code, X, Y, Z coordinate values, feed speed, and spindle speed.

As described above, when calculating the cutting force, the machining simulation system 3 applied to the present invention calculates the chip volume per edge in one CNC program block to erase the chip volume of the virtual workpiece, and calculates and predicts the cutting force using this chip volume. .

This embodiment of the present invention simulates a processing shape by removing a chip volume per edge in the same manner as a cutting situation of an actual milling machine, and can accurately predict a cutting force, so that the cutting situation can be accurately verified before work. Accordingly, according to the present invention, not only can the tool and the actual workpiece collide with each other during processing by predicting the machining situation before the actual workpiece machining operation, but also precise machining operation can be performed.

Subsequently, the processing process monitoring system 5 and its execution process according to the embodiment of the present invention will be described in detail with reference to FIGS. 7 and 8.

The processing process monitoring system 5 of the embodiment of the present invention includes a sensor compensation value loading unit 301, a current signal measurement unit 303, a cutting force calculation unit 305, an acceleration measurement unit 307, and a vibration calculation unit 309. , A monitoring determination unit 311, and an alarm control unit 313 may be included.

The sensor compensation value loading unit 301 is a program module that loads a value input by an administrator of the processing process monitoring system 5. Sensor compensation value The sensor compensation value loaded from the loading unit 301 is a value for calculating a measurement value comparable to the predicted value by compensating the values of the acceleration and current signals of the spindle measured in the actual processing system 1 and is a constant. I can.

The current signal measurement unit 303 may measure the cutting force of a tool used for cutting in the actual machining system 1 by using the signal measured by the current measurement sensor 13 installed in the machining system 1. The current signal measurement unit 303 may receive a value measured by the current measurement sensor 13.

The cutting force calculation unit 305 may calculate the cutting force of the actual tool using a value input to the current signal measurement unit 303 and a value of the sensor compensation value loading unit 301 to obtain a cutting force measurement value.

The acceleration measurement unit 107 may measure the vibration of the tool in the actual machining system 1 by using the signal measured by the acceleration sensor 15 installed in the machining system 1.

The acceleration measurement unit 307 may receive a value measured by the acceleration sensor 15.

The vibration calculation unit 309 may obtain a vibration measurement value by calculating the actual vibration of the tool using a value input to the acceleration measurement unit 307 and a value of the sensor compensation value loading unit 301.

The monitoring determination unit 311 receives the predicted cutting force predicted value and the vibration predicted value predicted by the machining simulation system 3, compares the cutting force measurement value and the vibration measurement value of the actual machining system 1, and displays it on a display device. It can be determined whether a condition occurs. That is, the monitoring determination unit 311 receives the predicted cutting force predicted value and the vibration predicted value from the machining simulation system 3, compares the cutting force measurement value and the vibration measurement value of the actual machining system 1, and displays the display device when the measured value is greater than the predicted value. Display and transmit the signal to the alarm control unit 313.

The alarm control unit 313 may display on the alarm display unit 17 installed in the processing system 1 according to a signal transmitted from the monitoring determination unit 311 and stop the processing system 1 at the same time.

The operation process of the processing process monitoring system 5 according to the embodiment of the present invention will be described in detail with reference to FIG. 8.

The sensor compensation value loading unit 301 loads the input cutting force compensation value and vibration compensation value (S501). The current signal measurement unit 303 receives a measurement signal from the current measurement sensor 13 (S503). At the same time, the acceleration measurement unit 307 receives a measurement signal from the acceleration sensor 15 (S503).

Further, the cutting force calculation unit 305 calculates a measured value of the actual cutting force of the tool by using the input value of the sensor compensation value loading unit 301 and the value of the current signal measurement unit 303 (S505). In addition, the vibration calculation unit 309 calculates a measurement value of the actual vibration of the tool by using the input value of the sensor compensation value loading unit 301 and the value of the acceleration measurement unit 307 (S505).

The monitoring determination unit 311 receives the cutting force predicted value and the vibration predicted value transmitted from the machining simulation system 3 (indicated by A in FIGS. 3 and 8), and compares the cutting force measurement value and the vibration measurement value, and the measured value is not larger than the predicted value. If not, the normal processing process monitoring system 5 is performed by returning to the previous step of measuring the acceleration and current signals. If the measured value is larger than the predicted value in the monitoring determination unit 311, since a problem has occurred in the actual processing system, a control signal is transmitted to the alarm control unit 313 (S507).

Then, the alarm control unit 313 controls to stop the operation of the processing system 1 and at the same time controls to operate the alarm display unit 17 of the processing system 1. Accordingly, the operator can monitor in real time an abnormal condition occurring in the cutting operation by comparing the predicted value predicted by the machining simulation system 3 with the measured value determined by the actual machining system 1.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and it is possible to implement various modifications within the scope of the claims and the detailed description of the invention and the accompanying drawings. It is natural to fall within the scope of the invention.

1. Processing system,
3. Machining simulation system,
5. Processing process monitoring system,
11. Machine tool control unit,
13, current measuring sensor,
15. acceleration sensor,
17. Alarm display,
31. Input,
33. Control,
35. Output,
37. Data storage,
131. Data loading unit,
133. Chip volume calculation unit per blade,
135. Cutting force calculation unit per edge,
137. Vibration value calculation unit,
139. Tool wear amount calculation unit,
141. Maximum cutting force and maximum vibration value extraction unit,
143. Processing simulation shape storage and output of the workpiece,
171. Basic data storage,
173. Cutting force data storage unit,
175. Vibration value data storage unit,
177. Tool wear data storage unit,
301. Sensor compensation value loading unit,
303. Current signal measuring unit,
305. Cutting force calculation unit,
307. Acceleration measurement unit,
309. Vibration calculation unit,
311. Monitoring judgment unit,
313. Alarm control

Claims (8)

The machining simulation system
An input unit that receives the shape of the tool, the shape of the workpiece, the cutting conditions and the code of each block in the CNC program, the coordinate values of the tool's X, Y, Z, the feed rate of the tool, and the spindle rotation speed data,
A simulation control unit that calculates a cutting force using data from the input unit,
A basic data storage unit that is input and output by the simulation control unit and stores data input through the input unit or optimizes and stores coordinate values, feed rates, and spindle speeds in the CNC program,
Includes an output unit for outputting a processing simulation shape of the workpiece by using the cutting force calculated by the simulation control unit,
The simulation control unit
By calculating the chip volume per tooth in each block of the CNC program, the calculated chip volume per tooth is erased, and the cutting force per tooth is calculated using the chip volume per tooth,
A chip volume calculation unit per blade that calculates the chip volume per blade of the tool,
A cutting force calculation unit per blade that calculates the cutting force of the tool by using the value calculated by the chip volume calculation unit per blade,
A vibration value calculation unit that calculates the vibration value of the tool by using the value calculated by the chip volume calculation unit per blade, and
And an extraction unit for extracting the highest cutting force from the values calculated by the cutting force per blade calculation unit, and extracting the highest vibration value from the values calculated by the vibration value calculation unit,
The highest cutting force and the highest vibration value extracted from the simulation control unit are input as a cutting force predicted value and a vibration predicted value, and the cutting force measured value and the vibration measured value are compared to the cutting force predicted value and the vibration predicted value by comparing the cutting force measured value and the vibration measured value measured in the processing system. If is large, stop the operation of the processing system,
Of the processing simulation system
The calculation formula for calculating the cutting force in the cutting force calculation unit,

Consists of
The formula for the volume compensation ratio is

Processing process monitoring system consisting of. The method according to claim 1,
The processing process monitoring system
A sensor compensation value loading unit that loads the sensor compensation value of the input cutting force and the sensor compensation value of the vibration,
A current signal measuring unit that measures the cutting force of the processing system,
A cutting force calculation unit that calculates a cutting force using the current signal measurement unit value and the sensor compensation value of the cutting force,
An acceleration measurement unit that measures the vibration of the processing system,
A vibration calculation unit that calculates vibration using a value of the acceleration measurement unit and a sensor compensation value of the vibration,
A monitoring determination unit comparing the predicted cutting force and vibration predicted value of the processing simulation system with the cutting force measured value calculated by the cutting force calculating unit and the vibration measured value calculated by the vibration calculating unit, and
An alarm control unit that receives a signal and stops the processing system when the cutting force measurement value and the vibration measurement value are greater than the cutting force predicted value and the vibration predicted value in the monitoring determination unit
Processing process monitoring system comprising a. The method according to claim 1,
Of the processing simulation system
The calculation formula for calculating the chip volume per blade in the chip volume calculation unit per blade,

Is represented by
Where s _p is the volume removed during each sampling simulation time d t ,

ego,

Is the cutting time per edge,
Cutting time per edge

Is,

Is represented by
Where S is the spindle speed (rpm),

Is the number of teeth of the tool
Processing process monitoring system consisting of. delete The method according to claim 1,
Of the processing simulation system
The vibration value of the tool calculated by the vibration value calculation unit is

Where the spring constant k is

Modeled with a multi-degree of freedom meter of the vibration equation of, and in the case of one degree of freedom, the displacement x (t) in the steady state of the forced vibration system by the predicted cutting force F _t is

Is,
Where X ₀ is the amplitude of vibration,

Is the phase, and the natural frequency is

Machining process monitoring system that outputs amplitude X ₀ as a vibration value. The simulation control unit of the machining simulation system
The step of receiving the shape of the tool, the shape of the workpiece, and the cutting conditions,
After the step of receiving the shape of the tool, the shape of the workpiece, and the cutting condition, the code of one block, the coordinate values of X, Y, Z of the tool, the feed rate of the tool, and the spindle rotation speed are sequentially determined in the CNC program. Loading from the basic data storage unit,
Calculating the cutting force of the tool after reading the code of the one block, the coordinate values of X, Y, Z of the tool, the feed rate of the tool, and the rotational speed of the spindle,
Determining whether the tool collides with the workpiece or generates excessive cutting force after calculating the cutting force of the tool,
In the step of determining whether the tool collides with the work or excessive cutting force occurs, outputting a warning message when the tool collides with the work or generates excessive cutting force,
After the step of determining whether the tool collides with the work piece or excessive cutting force occurs, if the tool does not collide with the work piece or does not generate excessive cutting force, it is determined whether one block of the CNC program has ended and one block is not finished. If not, determining the end of performing the block moving to before the step of calculating the cutting force,
In the step of determining the end of the block execution, when the execution of one block is completed, extracting the highest cutting force and the highest vibration value generated in the process,
After the step of extracting the highest cutting force and highest vibration value, outputting the processed shape output, the highest cutting force, and the highest vibration amplitude, and storing the output in a data storage unit, and
After the step of outputting the processing shape output, the highest cutting force, and the highest vibration amplitude, and storing it in the data storage unit, check if all the CNC programs have been executed, and if all CNC programs have been executed, terminate the program, and if the execution is not completed, In the CNC program, a block of G code, X, Y, Z coordinate values, feed speed, and spindle speed are returned to the previous step of receiving input,
The step of calculating the cutting force
By calculating the chip volume per tooth in one block of the CNC program, the volume of the virtual workpiece is eliminated and the cutting force is calculated.
The simulation control unit converts the cutting force peak value and the vibration peak value, respectively, to a cutting force predicted value and a vibration predicted value, and transmits it to a processing process monitoring system,
The processing process monitoring system
Loading the sensor compensation value of the input cutting force and the sensor compensation value of the vibration,
After the step of loading the sensor compensation value, measuring and measuring the current signal and acceleration of the machining system to calculate the cutting force and vibration of the machining system,
After measuring the cutting force and vibration of the processing system, calculating the cutting force and vibration using the value of the current signal measuring unit and the sensor compensation value of the cutting force,
After calculating the cutting force and vibration, receiving a cutting force predicted value and a vibration predicted value of the processing simulation system and comparing the cutting force measurement value and the vibration measurement value to determine whether the cutting force measurement value and the vibration measurement value are large, and
After determining whether the cutting force measurement value and the vibration measurement value are greater than the cutting force predicted value and the vibration predicted value, if the cutting force measurement value and the vibration measurement value are greater than the cutting force predicted value and the vibration predicted value, performing control to stop the processing system
Processing process monitoring method comprising a. The method of claim 6,
In the step of calculating the cutting force
The formula for calculating the cutting force in one block of the CNC program is

And the volume compensation ratio is

Is represented by the calculation formula of,
The formula for the chip volume per blade (S _th ) is

Where s _p is the volume removed during each sampling simulation time d t

ego,

Is the cutting time per edge,
Cutting time per edge

Is,

Is represented by
Where S is the spindle speed (rpm),

Is the number of teeth of the tool
Process monitoring method consisting of. The method of claim 6,
The vibration value of the tool is

Is represented by
Spring constant k is

Modeled with a multi-degree of freedom meter of the vibration equation of, and in the case of one degree of freedom, the displacement x (t) in the steady state of the forced vibration system by the predicted cutting force F _t is

Is,
Where X ₀ is the amplitude of the vibration,

Is the phase, and the natural frequency is

Machining process monitoring method that outputs amplitude X ₀ as a vibration value.

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