JP7362468B2 - Machined surface shape prediction device and method - Google Patents

Description

The present invention relates to an apparatus and method for predicting the shape of a machined surface formed by processing.

Patent Document 1 is known as a technique for performing shape processing using a cutting tool. Patent Document 1 states, ``For each block of data including feed axis position information, an NC program is used in which normal vector information indicating the normal vector of the machining surface at the contact point between the tool and the workpiece is written. Analyze the program for each block data, calculate the tool deflection correction amount according to the normal vector of the machined surface for each analyzed block data, and adjust the feed axis according to the calculated tool deflection correction amount. The position is corrected and shape processing is performed according to the corrected feed axis position.''

JP2005-144620

To evaluate the shape of the machined surface after cutting, measurement using a contact inspection probe or optical observation is used. The shape to be measured on the machined surface is, for example, squareness or surface roughness. A pass/fail judgment is made by evaluating whether the measured results are within the range specified at the design stage.

As cutting processes become more precise and finer, and the shapes of workpieces become more complex, it is becoming more difficult to measure the shape of workpieces. For example, if a hole is machined with a diameter of 1 mm or less and a depth of about 20 mm, even if you try to measure the shape of the machined surface, a contact-type inspection probe cannot be inserted, or the optical observation instrument will be at the limit of the optical depth. Measurement was difficult as there were some things that could not be done.

In addition, for large machined parts, it is necessary to inspect the quality of long machined surfaces, but since there is no dedicated measuring equipment, measurements are carried out at production sites by devising conventional measurement methods. . Since it is not a dedicated instrument, a lot of time is spent on inspections, such as having to measure multiple locations. Even if measurements were taken at multiple locations, it was difficult to understand the shape of the machined surface based on the results.

Patent Document 1 discloses that the magnitude and direction of the vector emitted from the machining surface toward the tool at each machining location, that is, the normal vector, are calculated in advance and reflected in the NC program as the amount of tool deformation, that is, the amount of correction. We aim to improve the precision of the machined surface shape.

In Patent Document 1, when evaluating the shape of a machined surface, the tool trajectory and the amount of tool deflection are taken into consideration, but changes in the shape of the machined surface due to deformation of a portion of the tool due to the load during actual machining are not considered. Therefore, highly accurate prediction of the shape of the machined surface cannot be performed. Furthermore, since the value of the normal vector is a fixed value and changes in machining load during machining are not taken into consideration, it is not possible to predict the highly accurate shape of the machined surface.

An object of the present invention is to provide a machined surface shape prediction device that can predict the shape of a machined surface with high accuracy in a shape that is difficult to inspect.

A preferred example of the present invention includes: a coordinate value acquisition unit that acquires position coordinate values of a tool in a processing machine during machining; a machining load acquisition unit that acquires a machining load on a drive shaft of the processing machine during machining; a tool volume measuring device that measures the volume of the tool; a DB that stores structural analysis information of a simulator obtained by converting the cross-sectional shape of the tool into a simplified cross-sectional shape based on the number of blades of the tool and the volume of the tool; Structural analysis information including the blade length and moment of inertia of the simulated body corresponding to the number of blades and material properties of the tool is received from the DB, the amount of deflection that the tool deforms due to the machining load is calculated, and the amount of deflection and The machined surface shape prediction device includes a prediction processing section that predicts the machined surface shape from the position coordinate values.

According to the present invention, it is possible to predict with high accuracy the shape of a machined surface in a shape that is difficult to inspect.

1 is a diagram showing the configuration of a machined surface shape prediction device in Example 1. FIG. FIG. 2 is a three-dimensional diagram illustrating the cutting section in FIG. 1. FIG. 3 is a diagram showing an NC program used in Example 1. FIG. 5 is a flowchart showing the processing procedure of the first embodiment. 5 is a flowchart showing details of processing step 17 in FIG. 4. FIG. 3 is a diagram showing temporal changes in cutting power on the X, Y, and Z axes in Example 1. 5 is a diagram showing changes in effective coordinate values of the X, Y, and Z axes in Example 1. FIG. The figure which shows the structure of a tool volume measuring device. A diagram comparing the static rigidity ratio of an actual tool and that of a simulated tool. FIG. 9 is a diagram in which the static stiffness ratio for a rectangular parallelepiped simulated body is added to FIG. An enlarged view of the overall shape of the workpiece after machining and the part used to compare the predicted shape of the machined surface. A diagram showing the shape of the actual machined surface, the predicted shape of the machined surface, and the designed shape. FIG. 7 is a diagram showing the configuration of a machined surface shape prediction device in Example 2. FIG. 7 is a diagram showing an example of the arrangement of a voltage detection probe and a clamp-type ammeter in Example 2. The figure which shows the change of the motor current in the X-axis, Y-axis, and Z-axis during the cutting process acquired by the clamp-type ammeter. A diagram showing the relationship between each axis motor current value and cutting power value.

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a shape prediction device in Example 1. A tool 2 is attached to the tip of a rotating main shaft of a processing machine 4, and a workpiece 3 is cut and machined into a designed desired shape by this tool 2.

A workpiece 3 (150 mm x 100 mm x 50 mm, made of carbon steel) is held by a machine vise 11 . The machine vise 11 is installed on a machining load measuring device 9 that can measure the force applied in each direction of the X, Y, and Z axes of the machining machine 4.

As the machining load measuring device 9, a cutting dynamometer was used to measure the force in each drive axis direction of the processing machine 4 during cutting. A cutting dynamometer uses a crystal piezoelectric element to convert the force applied in the direction of each drive axis during machining into voltage and outputs it to the outside.

The voltage output of the cutting dynamometer is digitally converted by the data collector 7 and stored in the computer 6. As the machining load measuring device 9, a strain gauge type cutting dynamometer may be used. By using such a cutting dynamometer, the cutting power in the processing machine 4 can be accurately measured. Here, the machining load is the cutting power applied to the drive shaft, and is the force that the tool 2 receives.

Further, one side of the communication cable 10 is connected to a communication connector installed in advance on the control panel 5 of the processing machine 4, and the other side is connected to a communication connector of the computer 6. The control panel 5 has the function of holding the current position coordinate values of the tool 2 on each drive axis of the processing machine 4, and the function of outputting the position coordinate value of the tool 2 allows the computer 6 to output the position coordinate value of the tool 2. take in.

In order to measure the volume of the tool 2, a tool volume measuring device 8 is installed in the processing machine 4. The voltage output of a liquid level sensor (not shown in FIG. 1) of the tool volume measuring device 8 is digitally converted by the data collector 7 and stored in the computer 6.

The machined surface shape prediction device 1 is based on the four components installed inside the frame indicated by the broken line in FIG. It is configured.

Next, cutting by the processing machine 4 will be explained. FIG. 2 is a three-dimensional diagram illustrating the cutting portion of FIG. 1 in detail. The tool 2 attached to the rotating main shaft of the processing machine 4 starts rotating toward a predetermined rotation speed by the rotation of the main shaft motor. As tool 2, a square end mill made of carbide material and having a tool diameter of 12 mm was used. The rotation direction 13 of the main shaft was clockwise, and the rotation speed was 3185 revolutions/minute. At the start of rotation, the tool 2 is waiting at the machine coordinate origin (X=0, Y=0, Z=0) preset in the processing machine 4.

When the rotation speed of the tool 2 reaches a predetermined rotation speed, the tip of the tool 2 moves to the starting coordinate 14 (X= 165, Y=-5, Z=-15) and wait. The X-axis, Y-axis, and Z-axis are feed axes for giving a feed motion to the workpiece. A drive motor for each axis is arranged to effect the feed movement of each axis. The X-axis, Y-axis, and Z-axis are also drive axes of a motor that moves the tool 2.

By setting the start coordinates 14, the depth of cut in the Y-axis direction and the depth of cut in the Z-axis direction when machining the workpiece are set. In this example, the depth of cut in the Y-axis direction was 1.0 mm, and the depth of cut in the Z-axis direction was 15 mm.

After that, the tool 2 moves in the tool feed direction 12 while rotating, and moves to the end point coordinates 15 (X=-15, Y=-5, Z=-15) indicated by "◎" in FIG. This is how it is done. In this example, the feed amount per rotation of the tool was 0.03 mm/rotation.

An NC program as shown in FIG. 3 is provided to the control panel 5 of the processing machine 4 by manually inputting it into the control panel 5, or by transferring an NC program created in advance using an external computer (not shown). The series of operations of the processing machine 4 are controlled by the control panel 5 executing the program according to the NC program.

Next, the NC program shown in FIG. 3 will be explained. First, the percentages in the first and tenth lines indicate the data start and data stop positions of the NC program. O1000 on the second line indicates the name of this program.

#1=0.03 in the third line substitutes the machining condition, which is the feed amount per revolution of 0.03 mm/one revolution, to variable #1.

#2=4 on the fourth line assigns the number of blades of the tool to be used to variable #2. The input value to #2 is re-entered as appropriate depending on the tool used.

The next fifth line, #3=#1*#2*3185, calculates and substitutes the tool feed rate into variable #3.

In this embodiment, #3=382 is calculated and assigned to #3 from the values of variables #1 and #2 and the value of the rotational speed of 3185 revolutions/minute. S3185 on the 6th line indicates the command value of the rotation speed of the rotating main shaft. In this example, the rotation speed is 3185 revolutions/minute.

Next, M03 described is a command to start rotating the rotating main shaft in the clockwise direction. The G numbers from the seventh line onward each indicate a preparation/actual operation command for the processing machine 4. G00 is a so-called positioning operation in which actual machining is not performed, but immediate movement is made to a specified coordinate position. G01 is a linear motion that is actually processed. G90 is a description of an absolute command to perform axis movement using coordinate values with the set coordinate origin as 0.

Therefore, in the 7th line, the position is 165 mm in the X direction, -5 mm in the Y direction, and -15 mm in the Z direction, and in the 8th line, the position is moved 165 mm in the negative direction of the X axis in a linear machining operation. F#3 written on the 8th line is a tool feed speed command, and 382 is substituted for #3, so the tool moves at a speed of 382 mm/min to machine an arbitrary shape. . M05 on the ninth line is a command to stop the rotation of the rotating main shaft. M02 on the 10th line indicates the end of the NC program.

FIG. 4 is a flowchart showing the processing procedure of the computer 6 in the machined surface shape prediction device in the first embodiment. The steps will be explained sequentially according to this flowchart. In this embodiment, the flowcharts in FIGS. 4 and 5 are processes executed by the computer 6. A processor such as a CPU in the computer 6 reads a program recorded on a recording medium, and each processing section such as a coordinate value acquisition processing section, a machining load acquisition section, and a prediction processing section executes each step as described below. Then, processing for predicting the shape of the machined surface can be realized.

In processing step 16, the user inputs information regarding processing, and the computer 6 sets and stores the input information in the storage medium. The information regarding machining includes the machining direction during machining, that is, up-cut or down-cut, the blade length L of tool 2, the depth of cut in the Z-axis direction, the tool radius of tool 2, the number of teeth of tool 2, and the tool 2. material property values (for example, Young's modulus, Poisson's ratio), etc.

In processing step 17, the coordinate value acquisition unit acquires the position coordinate values of the tool 2 from the processing machine 4. Further, the machining load acquisition unit acquires the machining load. A flowchart showing processing step 17 in detail is shown in FIG.

The flowchart of FIG. 5 will be explained in order. First, in processing step 23, the computer 6 receives a data acquisition start command from the processing machine 4 to start acquiring dynamometer data, which is the machining time, the position coordinate value of the tool 2, and the machining load. Thereafter, the computer 6 gives a command to start cutting to the processing machine 4 in step 24, and the computer 6 acquires the position coordinate values of the tool 2, dynamometer data that is the processing load, and processing time. do.

When the cutting process is completed, a cutting completion command is transmitted from the processing machine 4 to the computer 6 in a processing step 25. In response to the cutting completion command, in processing step 26, the coordinate acquisition unit of the computer 6 completes acquisition of the position coordinate values of the tool 2, the machining load acquisition unit completes acquisition of dynamometer data, and the computer 6 completes acquisition of the position coordinate values of the tool 2. Complete acquisition of machining time from 4.

FIG. 6 is a diagram showing changes in cutting power on the X, Y, and Z axes acquired when the machining load measuring instrument 9 shown in FIG. 1 performs cutting using the NC program shown in FIG. 3. In the upper, interrupted, and lower rows of FIG. 6, the horizontal axis is time, and the vertical axis is cutting power. The upper row shows the change in cutting power for the X-axis, the middle row for the Y-axis, and the lower row for the Z-axis. The portion where the amplitude of the cutting power is large from around 20 seconds to around 35 seconds is the cutting power during actual cutting.

FIG. 7 is a three-dimensional diagram of the effective coordinate values of the X, Y, and Z axes during positioning movement and cutting, which were obtained by the computer 6 using the functions of the control panel 5 of the processing machine 4 shown in FIG. It is something. The time interval when acquiring each coordinate data was 2.5 ms. From this data, it can be confirmed whether the system is operating according to the contents instructed by the NC program shown in FIG. 3, and detailed effective coordinate values between the coordinates specified by the NC program can be obtained.

Although only the start and end coordinates are listed in the 7th and 8th lines of the NC program in FIG. 3, the effective coordinates of the tool 2 can be acquired by using the coordinate acquisition method described above, Since it is known what route the material was cut through the workpiece 3 by the workpiece 2, it is possible to roughly predict the shape of the surface of the workpiece 3.

Returning to the flowchart in FIG. 4, the explanation will proceed. In processing step 20 in FIG. 4, the prediction processing unit obtains the volume of the tool and records the volume. FIG. 8 shows a tool volume measuring device and a measuring method.

FIG. 8 is a diagram showing the configuration of the tool volume measuring device 8. As shown in FIG. The tool volume measuring device 8 includes a U-shaped tube 28 into which a tool volume measuring liquid 27 is injected, and a liquid level sensor 29 attached to one opening of the U-shaped tube 28. The measurement principle of the tool volume measuring device 8 uses the Archimedes method.

In the measurement procedure of the tool volume measuring device 8, first, the liquid level position in a state where the tool 2 is not inserted is stored as the output voltage U0 of the liquid level sensor 29. Thereafter, the tool 2 is inserted into the tool volume measuring liquid 27 by the Z-axis movement of the processing machine 4. When inserting the tool 2 into the tool volume measuring liquid 27, insert it up to the part of the tool 2 that has a cutting function, that is, the blade part.

Insertion of the tool 2 causes a change in the liquid level of the tool volume measuring liquid 27, and the output voltage of the liquid level sensor 29 changes to a voltage value U1. From the relational expression between the output voltage of the liquid level sensor 29 and the volume, which was obtained separately, the volume V0 (initial volume shown in FIG. 8) when the output voltage of the liquid level sensor 29 is U0, and the volume V1 when the output voltage U1 is Find each. A difference ΔV between the volume V1 and the initial volume V0 is determined, and this is taken as the actual volume of the tool 2.

As the liquid level sensor 29 in FIG. 8, it is preferable to use an ultrasonic liquid level sensor that emits ultrasonic waves, receives the ultrasonic waves reflected on the liquid surface, and measures the distance based on the time from the emission to the reception. Moreover, water, oil, etc. can be used as the tool volume measuring liquid 27. In this example, the cutting coolant of the processing machine 4 was used. In FIG. 8, the U-shaped tube 28 is shown as having light transmittance for convenience of explanation, but a material without light transmittance may be used.

Based on the actual volume of the tool 2 measured as described above, in step 21 of the flowchart of FIG. 4, the prediction processing unit simplifies the tool shape for structural analysis. Here, the tool shape is simplified and assumed to be a round bar shape. In this embodiment, they will be referred to as a simplified object and a simulated object.

The tool shape is simplified using the following steps. First, the radius R of the simulant is determined by dividing the actual volume of the tool 2 measured in processing step 20 by the blade length L of the tool 2 set and stored in processing step 16 and obtaining the square root. Based on these calculation results, the simulated body is assumed to be a round bar shape with a diameter of 2×R and a length equal to the blade length L of the tool 2.

In FIG. 9, the horizontal axis shows the static rigidity ratio of the tool when the static rigidity of the tool A1 when the tool 2 forms the tool shape is set to 1, and the vertical axis shows the static rigidity ratio of the tool A1 when the tool 2 forms a tool shape. The static stiffness ratio of the simulated body is shown when the static stiffness is set to 1.

Here, regarding the static rigidity ratio, for example, the static rigidity ratio is calculated from the static rigidity B of a tool A1 with 5 blades and a diameter of 5 mm, based on the static rigidity A of a tool with a diameter of 10 mm and 4 blades. Decide on B/A. In other words, the static rigidity ratio of other tools is determined by the ratio of the static rigidity of other tools with different numbers of teeth and diameters to the static rigidity of the reference tool.

The markers indicated by "○" in Fig. 9 are the static rigidity ratios of three types of tools with different tool diameters and number of teeth, and the static rigidity ratios when the tool volume of each tool is measured and simplified into a simulated body. It shows.

The correlation coefficient in FIG. 9 is as high as 0.999, and the method of this embodiment, which simplifies the tool volume to a simulant, is appropriate.

The static rigidity of the tool 2 having three or more teeth exhibits the same numerical value in any direction in the radial direction of the tool, that is, exhibits isotropy. However, when the number of teeth of the tool 2 is 2 or less, the static rigidity differs in the radial direction of the tool, that is, anisotropy is exhibited. Therefore, when a tool with two or fewer blades is selected as the tool 2, it is not simplified to a round bar-shaped simulant, but is simplified to a rectangular parallelepiped whose height is equal to the blade length L of the tool 2. The vertical and horizontal lengths of the bottom, excluding the height of the rectangular parallelepiped, are calculated using the following method.

First, in processing step 16, the actual volume of the tool 2 is divided by the blade length L of the tool 2, which has been set and stored, to obtain the area A.

It is assumed that an imaginary line is connected in the radial direction of the tool 2 and is defined as the X-axis, and that an axis perpendicular to the X-axis is the Y-axis. In the inventors' study, it was found that when the number of teeth of the tool 2 is 2 or less, if the tool diameter in the X-axis direction is 10, the tool diameter in the Y-axis direction is approximately 7. That is, the aspect ratio is 0.7. While maintaining this aspect ratio of 0.7, determine the length of the bottom surface that will give area A.

The vertical and horizontal lengths are determined using a solver. In the solver, the aspect ratio is set as a target value of 0.7, and vertical and horizontal solutions are obtained within a range that does not deviate from the maximum diameter of the tool 2.

When the static rigidity ratio of the tool shape and the static rigidity ratio of the rectangular parallelepiped simulator are added to FIG. 9 when the number of blades of the tool 2 obtained by the above method is 2 or less, it becomes as follows. What is indicated by the "□" marker in FIG. 10 is the comparison result when the number of teeth of the tool 2 is 2 or less. The data for the case where the number of teeth of the tool 2 is 2 was also plotted on the approximate straight line showing the correlation coefficient of 0.999, which was also shown in the explanation of FIG. 9 above, and it was confirmed that the data was valid.

From these, in the machined surface shape prediction method of Example 1, when the number of teeth of tool 2 is 3 or more, the number of teeth of tool 2 is In the case of 2 or less, an algorithm for simplifying each to a rectangular parallelepiped-shaped simulated body is executed in processing step 21.

In the processing machine 4, since a plurality of tools are used during the cutting process, processing steps 20 and 21 are performed for each tool stored inside the processing machine 4. information is stored in a DB (database) 22.

After processing load/coordinate value data is acquired in processing step 17, in processing step 16, the number of teeth of tool 2 and material characteristic values of tool 2 set in advance are read, and a simulation is performed according to these tool information. The body information is queried to the DB 22, and the DB 22 passes the answer to the processing step 18 in response. The answer results include the blade length L of the simulated tool 2 and the moment of inertia of area.

In processing step 18, the prediction processing unit calculates the deflection of the tool 2 by calculating the structure of the simulated body from the blade length L of the simulated body of the tool 2, the moment of inertia, and the material property value information of the tool 2. Calculate quantity. The amount of deflection is calculated from the general formula (1) for the amount of deflection of the free end beam.

In equation (1), σ is the amount of deflection, and K is the coefficient of deflection, which is set to 1/3. Next, W is the load applied to the end of the beam, L is the blade length of the simulated tool 2 in this example, E is the Young's modulus of the tool 2, and I is the cross-sectional quadratic of the simulated tool 2 in this example. It's a moment. In the case of this embodiment, W is the cutting power acquired in processing steps 23 to 26.

Next, in processing step 19, the prediction processing unit extracts the cutting power for each machining time obtained in processing steps 23 to 26, and calculates the amount of tool deflection according to the cutting power. Furthermore, the amount of tool deflection is added to the effective coordinate value of the tool for each machining time. Then, the added value of the effective coordinate value and the amount of tool deflection is developed on a three-dimensional space for each machining time. The machined surface shape is predicted by the values developed in the three-dimensional space.

The results of side surface machining of a workpiece will be described using the NC program shown in FIG. 3 and using a carbide end mill with a tool diameter of 12 mm and a number of teeth of 4 as the tool 2.

FIG. 11 is an enlarged view of the overall shape of the workpiece after being machined and a portion used for comparison of the predicted shape of the machined surface.

In this example, the cutting power in the Y-axis direction, which is particularly susceptible to tool deflection, was 100 N from the machined surface of the workpiece 3 (indicated by a-a'-b in FIG. 11). The shape (cross section) of the machined surface in the coordinates was extracted and compared.

FIG. 12 is a diagram showing the shape of the actual machined surface, the shape of the machined surface predicted by the machined surface shape prediction device of this embodiment, and the design shape assumed from the NC program and the tool outline. In this example, the shape of the actual machined surface was measured using a non-contact laser displacement meter. A-a'-b in FIG. 12 corresponds to a-a'-b in FIG.

As can be seen from FIG. 12, the actual machined surface is formed to the right in FIG. 12 because the tool is deflected due to the machining load with respect to the designed shape (indicated by the dotted line in FIG. 12). The results predicted for this actual machined surface using the machined surface shape prediction method and the machined surface shape prediction device of this embodiment are indicated by "O" in FIG. It can be seen that the machined surface shape calculated using the machined surface shape prediction method of this example and the actual machined shape are very well reproduced.

By using the machined surface shape prediction device of Example 1, it becomes possible to predict the shape of the actual machined surface. Therefore, it becomes possible to evaluate the shapes of machined surfaces, such as complex shapes and minute shapes, which have been difficult to measure in the past.

FIG. 13 is a diagram showing the configuration of a machined surface shape prediction device in Example 2. In Example 2, the machining load measuring device 9 shown in FIG. 1 was replaced with a table for the workpiece.

Furthermore, in the second embodiment, a part of the motor wiring 32 is wired between the inverter 30 of each axis motor installed in the control panel 5 and the motor 31 installed in each axis of the processing machine 4. As shown in FIG. 14, a voltage detection probe 33 of a clamp type ammeter 34 is installed. The clamp-type ammeter 34 is a machined surface shape prediction device that measures the load of each drive motor that provides the power to move the tool 2 or workpiece 3 in the direction of each drive axis such as the X-axis, Y-axis, and Z-axis. was configured.

As a clamp-type ammeter, for example, a voltage detection probe 33 that has a frequency band from DC to several tens of kHz and has an input current range capable of measuring the rated current of the motor driven by each drive shaft is connected. . As the clamp-type ammeter 34, a measuring instrument that can display the current value detected by the voltage detection probe 33 and output data through communication with the computer 6 can be used.

FIG. 14 is a diagram showing an example of the arrangement of the voltage detection probe and the clamp-type ammeter in the second embodiment. In FIG. 14, a voltage detection probe 33 and a clamp-type ammeter 34 are installed between the processing machine 4 and the control panel 5. The arrangement is not limited to this arrangement, and the voltage detection probe 33 and clamp-type ammeter 34 may be installed inside the processing machine 4 as long as it is possible to measure the current of the motor driven by each drive axis during processing. However, the voltage detection probe 33 and the clamp-type ammeter 34 may be installed in the control panel 5.

FIG. 15 is a diagram showing changes in the motor currents of the X, Y, and Z axes during cutting, which are obtained using a clamp-type ammeter.

FIG. 16 is a diagram showing the relationship between the motor current value and the cutting power value in the drive shaft. As shown in FIG. 16, the motor current value and the cutting power value have a relationship expressed by a linear equation, and can be replaced with the cutting power value by multiplying the motor current by a predetermined coefficient.

Although FIG. 16 shows only an example of the motor current value that drives movement in one axis direction, the relationship between the motor current value and the cutting power value for any of the X, Y, or Z axes is similar. There is a relationship.

By replacing each axis motor current with the cutting power value, it becomes possible to predict the shape of the machined surface in the same manner as the machined surface shape prediction device shown in the first embodiment.

In this embodiment, the motor current value for each axis has been described, but the power value for each axis calculated by multiplying the motor current value by the motor applied voltage value can be similarly used. In this embodiment, the machining load section can obtain the machining load corresponding to the cutting power value from the motor current or electric power of the drive shaft.

In the above embodiment, the coordinate value acquisition unit of the computer 6 acquires the current coordinate values of each drive axis of the processing machine 4 held by the control panel 5 of the processing machine. By doing so, the position coordinates of the tool 2 on the drive shaft can be obtained using the functions provided in the processing machine 4 as is, and there is no need to add any other device.

There may be cases where the computer 6 cannot communicate with the processing machine 4. In that case, a measurement section such as a sensor that measures the amount of displacement of the tool 2 is installed separately from the processing machine 4, and the measurement section detects the amount of displacement of the tool 2 based on a reference point in the processing machine 4, for example. , the coordinate acquisition unit of the computer 6 may acquire the position coordinate values of the tool 2.

Although the embodiments made by the present inventors have been described above, it goes without saying that the embodiments are not limited to the above embodiments and that various changes can be made without departing from the gist thereof. For example, the above embodiments are described in detail for easy understanding, and the embodiments are not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations.

Furthermore, in the figures, control lines and information lines are shown that are considered necessary for explanation, and do not necessarily show all control lines and information lines on implementation. In reality, almost all configurations may be considered to be interconnected.

1: Machining surface shape prediction device, 2: Tool, 3: Workpiece, 4: Processing machine, 5: Control panel, 6: Computer, 7: Data collector, 8: Tool volume measuring device, 9: Machining load measurement vessel

Claims (12)

a coordinate value acquisition unit that acquires position coordinate values of a tool in a processing machine during processing;
a machining load acquisition unit that acquires a machining load on a drive shaft of the processing machine during machining;
a tool volume measuring device that measures the volume of the tool;
a DB storing structural analysis information of a simulant whose cross-sectional shape of the tool is converted into a simplified cross-sectional shape based on the number of blades of the tool and the volume of the tool;
Structural analysis information including the blade length and moment of inertia of the simulated body corresponding to the number of blades and material properties of the tool is received from the DB, the amount of deflection that the tool deforms due to the machining load is calculated, and the amount of deflection is calculated. and a prediction processing unit that predicts the shape of the machined surface from the position coordinate values. The machined surface shape prediction device according to claim 1,
The coordinate value acquisition unit is a machined surface shape prediction device that acquires coordinate values held in a control panel of the processing machine. The machined surface shape prediction device according to claim 1,
The coordinate value acquisition unit includes a measurement unit that measures the amount of displacement of the tool from a reference point,
A machined surface shape prediction device that acquires the position coordinate values from the measurement unit. The machined surface shape prediction device according to claim 1,
The machining load acquisition unit is a machined surface shape prediction device that acquires cutting power from a strain gauge type or crystal piezoelectric type cutting dynamometer. The machined surface shape prediction device according to claim 1,
The processing load acquisition unit includes:
A machined surface shape prediction device that acquires a detected current value or power value by installing a probe in wiring between a motor on the drive shaft and an inverter of the motor. The machined surface shape prediction device according to claim 1,
A machined surface shape prediction device in which the drive shaft is a feed shaft that provides a feed motion to the tool. The machined surface shape prediction device according to claim 1,
The DB stores structural analysis information of a round bar-shaped simulant when the number of blades of the tool is 3 or more, and stores structural analysis information of a rectangular parallelepiped simulant when the number of blades of the tool is 2 or less. Machined surface shape prediction device. The coordinate value acquisition unit acquires the position coordinate values of the tool on the processing machine during processing,
A machining load acquisition unit acquires a machining load on a drive shaft of the processing machine during machining,
a tool volume measuring device measures the volume of the tool;
A DB stores structural analysis information of a simulator obtained by converting a tool cross-sectional shape into a simplified cross-sectional shape based on the number of blades of the tool and the volume of the tool,
A prediction processing unit receives structural analysis information including the blade length and moment of inertia of a simulated body corresponding to the number of blades and material properties of the tool from the DB, and calculates the amount of deflection that the tool deforms due to the machining load. , a machined surface shape prediction method for predicting a machined surface shape from the amount of deflection and the position coordinate values. The machined surface shape prediction method according to claim 8,
The DB stores structural analysis information of a round bar-shaped simulant when the number of blades of the tool is 3 or more, and stores structural analysis information of a rectangular parallelepiped simulant when the number of blades of the tool is 2 or less. A method for predicting the shape of machined surfaces. The machined surface shape prediction method according to claim 8,
The machining surface shape prediction method is characterized in that the machining load is cutting power applied to the drive shaft. The machined surface shape prediction method according to claim 8,
The machining load is calculated from the motor current or motor power of the drive shaft. A program for causing a computer to execute the machined surface shape prediction method according to claim 8.

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